Purse Seine Fisheries of Thailand

Purse Seine Fisheries of Thailand
Compiled by
Weerasak Yingyuad1 and Isara Chanrachkij2
Training Department
Southeast Asian Fisheries Development Center
TD/LN/121
June 2010
Purse Seine Fisheries in Thailand
Compiled by
Weerasak Yingyuad1 and Isara Chanrachkij2
Training Department
Southeast Asian Fisheries Development Center
1
: Coastal and Small Scale Fisheries Management Division
: Capture Fisheries Technology Division (Correspondence person)
Preface
This report is purposed for recover the fishing technology skill on coastal purse
seine before attended the research works on coastal purse seine fishing technology
improvement, carried out by Tokyo University of Marine Science and Technology, Tokyo
Japan. The research works is able to separate into 2 main categories, i.e. Purse seine net
improvement by the study on mesh construction characteristic between horizontal net stripe
and vertical stripe. The other research work is study on the feasibility to operate purse seine
by Norwegian technology adaptation.
Authors, SEAFDEC Fishery researchers, have already comprehended on Japanese
Purse seine style, one-boat mackerel purse seine that using various deck hauling devices, e.g.
Purse winch, Purse drum, net shifter, net hauler, etc, regarding to the enrolled on MV Platoo,
SEAFDEC coastal purse seiner. She, however, has been retired since year 2004.
On the occasion, the participating on research work under Tokyo University of
Marine Science and Technology at Tateyama Fisheries Training Station, Chiba Prefecture
during 6-16 July 2009 is granted under JSPS-NRCT (Japanese Society for Promotion of
Science- National Research Council of Thailand) support. Authors have to brush up the
knowledge and skillful of purse seining in order to facilitate with this research works. By this
reason, review on Purse Seine Fisheries of Thailand was compiled by gathering information
related on Thai purse seine, as well as history of Thai purse seine and status of pelagic
resources of Thai purse seine fisheries has been carried out. Research method is the
compiling of secondary data from various fishing gear texts what fishing gear technologists,
both Thai and foreign, have already conducted then presented within this report.
Authors sincerely wish that this report shall be advantage for fishing gear
technologists and others who interested in Thai purse seine fisheries. Authors also take
responsibility on mistaken information in this report and author shall be greatly appreciated
in every discussion on this report with who interested in purse seine fisheries and extended all
merit of this report to JSPS-NRCT program.
Contents
Page
Contents
List of Figures
List of Tables
Introduction: Purse Seine in General
Background of Thai Purse Seine Fisheries
History of Thai Purse Seine Fisheries
Statistics on Thai Purse Seine Fisheries
10
Categories of Purse Seines in Thailand
15
Categories of Surrounding Nets Classified by the Department of

Fisheries of Thailand
16
Categories of Surrounding Nets Classified by SEAFDEC/TD
36
Categories of Surrounding Nets Classified by FAO (ISSCFG)
39
Principles of Thai Purse Seine Fishing Operations
44
Thai Purse Seiner
50
Design of Fish Aggregating Devices (FADs) for Purse Seining in Thailand
51
Pelagic Resources for Thai Purse Seine Fisheries
54
Appendices
61
Appendix 1: Thai Fisheries in General
61
Appendix 2: Statistics on marine catch by purse seines (1955-2006)
63
Appendix 3: Number of Purse Seiners in Thailand (1955-2006)
65
Acknowledgement
67
References
68
Purse seine Fisheries of Thailand: Weerasak Yingyaud and Isara Chanrachkij

SEAFDEC/TD, Samutprakarn Thailand
List of Figures
Figure No.
1
Siamese purse seine type I (Uan Lard in Thai): Single boat
method
2
Siamese purse seine type I (Uan Lard in Thai): Multi-vessel
operation
3
Quantity of catch in metric tons by marine capture and purse
seine fisheries (1974-2006)
4
Quantity of catch (in metric tons) by type of purse seine
(1974-2006)
5
Number of purse seiners in Thailand classified by type (19742006)
6
Significant fishing ports of Thai purse seiners
7
Important fishing grounds for Thai purse seine fishing in the
Gulf of Thailand
8
Beach seine of Thailand
9
Surrounding net without a purse line (mesh size larger than 10
mm)
10
Fishing operation of surrounding net without a purse line
(mesh size larger than 10 mm)
11
Surrounding net with a purse line (mesh size less than 10 mm)
12
Fishing operation of surrounding net with a purse line (mesh
size less than 10 mm)
13
Purse seiner of surrounding net with a purse line net (mesh
size less than 10 mm): Malaysian and Thai models
14
Luring light boats at a fishing port in Rayong Province
15
size 10.0-24.9 mm)
16
size 25.0-29.9 mm)
17
Surrounding net with a purse line (mesh size 25.0-29.9 mm):
Free schooling surrounding method
18
size 25-29.9 mm): Free schooling surrounding method
19
Surrounding net with a purse line (mesh size 25-29.9 mm):
Luring light surrounding method
20
Fishing operation of surrounding nets with a purse line (mesh
size 25-29.9 mm): Luring light surrounding method
21
Surrounding net with a purse line (mesh size 25-29.9 mm):
FAD surrounding method
22
size 25-29.9 mm): FAD surrounding method
Page
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Two-boat purse seine (Uan Tang-ke)

Fishing operation of two-boat purse seine (Uan Tang-ke)
Two-boats purse seiner
Surrounding net with a purse line (mesh size 30-45 mm)
Surrounding net with a purse line II (mesh size 30-45 mm)
Fishing operation of surrounding net with a purse line: freeschooling search by hydro-acoustic equipment
Categories of surrounding nets classified by FAO
Categories of Thai surrounding nets classified by the
Department of Fisheries of Thailand
Categories of Thai surrounding nets classified by
SEAFDEC/TD
Thai anchovy purse seiner
Local FAD in a fishing ground of the Andaman Sea
Construction of FAD (Sung) for Thai purse seining in the
central part of the Gulf of Thailand
Rastrelliger brachysoma
Rastrelliger kanagurta
Sardinella gibbosa
Sardinella frimbriata and Sardinella albella
Decapterus maruadsi and Decapterus macarellus
Encrasicholina heteroloba
Thunnus tonggol, Euthynnus affinis, and Auxis thazard
Thailand EEZ
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List of Tables
Table No.
1
2
3
4
5
Evolution of purse seine fisheries in Thailand

Comparison of the categories of surrounding nets
Comparison of the types of surrounding nets with and without
purse line
Techniques adopted in fishing with surrounding nets (with
purse line) with the corresponding main target species
The marine fisheries management measures in Thailand
Page
10
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59-60

1.
Introduction: Purse Seine in General
Purse seine is one of the most advance types of fishing gears for surrounding schools
of fish, e.g. anchovies, sardines, scads, mackerel, bonito and tuna. Purse seine was developed
from two different fishing gears and methods, i.e., Beach seine and Lampara. Purse seine has
been used for more than 200 years while the modified purse seine started to evolve only
about 100 years ago (Ben-Yami, 1994).
Nowadays, purse seine is still widely used by fishers in almost every parts of the
world although with various modifications of the fishing gears and methods. From the
different modifications of the fishing techniques, purse seine has been called by many names,
e.g. purse seine net, ring net, two-boat purse seine, etc., where purse seine net generally
consists of pieces of rectangular nettings, float line with float attached at the top, and sinker
line with sinker attached at the lower side. The most salient feature of a purse seine is its
ability to encircle and impound schools of fish from the bottom which can be closed by either
a hook (in case of no purse line) or a purse line that passes through the purse rings at the end
of the bridle rope attached to the sinker line at regular intervals, to prevent the fish from
escaping through the bottom of the net (SEAFDEC, 1988).
At present, purse seine fishery shares the large portion of the worlds total catch from
marine fisheries. Clupeoids fisheries in South America, i.e. Peru and Chile, and African
coasts of Angola and Namibia, accounted for a massive catch and became one of the worlds
top ranking fisheries in terms of marine fish production every year. Tuna purse seine fishery
is also another major fishing operation that share large quantities of catch every year.
Notwithstanding the technology innovations and massive investments in modern vessels in
tuna and clupeoid fisheries, the great contributor to purse seine fisheries of the world is the
vast number of small vessels landing small quantities of many kinds of fish species. These
small vessels have multi-purpose uses and thus, it is difficult to come up with the exact
estimate of the number of vessels involved in purse seine fisheries. However, a conservative
estimate of the percentage of the catches by surrounding net fisheries would be 25% to 30%
of the world catch from marine fisheries (Ben-Yami, 1994).
Federico (1997) noted that the worlds purse seine fisheries had been mobilized by the
requirements of the fisheries product processing industry as well as the varied market
destinations. Catches from purse seine fisheries have two main categories of utilization, i.e.
(1) direct human consumption, and (2) indirect human consumption. Although the catch
species for direct human consumption are the large and medium size fishes, small species like
anchovies and sardines continue to dominate as the target species for many Asian countries.
The category on indirect human consumption is mainly in the form of fish meal for animal
feeds. By definition and efficiency, small pelagic species are more profitable to be caught by
purse seine.

However, there is now a trend of utilizing fish species, e.g. horse mackerel, sardines
and anchovies that could produce fish meals with high protein concentration required for
better animal production, especially in the Chilean and Peruvian fish meal industries.
Although there is a current trend to focus more on direct human consumption, fish
meal products command good market price and are highly in demand. As a consequence,
harvesting of the pelagic resources is expected to be in high quantities in the long term. Thus,
purse seining technology should be continuously improved in order to reduce the cost of
investments and enhance quality and quantity of the catches while at the same time
conserving the resources.

2.
Background of Thai Purse Seine Fisheries
2.1
History of Thai Purse Seine Fisheries
Surrounding nets have been used by Thai fishermen in coastal waters for a long time.
Initially, these were small-scale gears used for catching planktonic shrimps, anchovies and
other species found in shallow waters near the shore. Small cotton net was used by the
fishermen with or without using rowing-boats. Later, two wooden poles were added to the
gear for closing the bottom part of the net. This type of purse seine could be operated in
either day or nighttime to catch Indo-Pacific mackerel and mixed schools of fish composed
mainly of herrings, croakers, Indo-Pacific mackerel, thread-fin and sting ray (SEAFDEC,
1986).
Nomura and Yamasaki (1975) reported that Chinese fishermen from Fukien Province
of China introduced the Chinese ring-net sometime in 1926. DOF/Thailand (1953) has
categorized Chinese purse seine into two-boat purse seine and officially named in English as
Chinese purse seine type II or Uan Tang-ke in the Thai language, but later, this was renamed
as Chinese purse seine. The Chinese purse seine type II or Uan Tang-ke is operated using one
large sailing boat as mother boat and two rowing boats. The net made of cotton yarn, is dyed
using a liquid produced from the mangrove bark. This information is consistent with the
report by Boon-lert (1987) which indicated that that the Chinese fishers operated the purse
seine using a big sailboat with 2 small skiff boats, and targeted the Indo-pacific mackerel.
The operation of the Chinese purse seine using the same procedure as the original method,
continued until the mid of 1990.
Preparation of the Chinese purse seine operation starts with the loading of the purse
seine net into the two (2) rowing boats fastened with the stern of the mother boat. When a
fish school is located, the mother boat is maneuvered close to the fish school and the rowing
boats are released. The rowing boats set the net in crossed direction with the fish school
moving until completely surrounding the fish school. The purse line is manually hauled while
2 crew members use paddles and splash the at sea surface in order to prevent the escape of
the fish school from the net gap. Then the net panel is hauled by the crew onboard the 2
rowing boats until reaching the bunt part. The mother boat then comes to the net circle and
the crew scoops the catch, load onboard the mother boat, and store in the fish holds.
Although it has been official recorded that Uan tang-ke was introduced into the
Kingdom of Thailand in 1926, the Siamese purse seine type I or Uan Lard in the Thai
language, was first invented by Chinese fishers who migrated from China, but such
information had not been recorded (Interview with Mr. Aussanee Munprasit in 28 June
2009). The first official record of the Department of Fisheries of Thailand (DOF/Thailand)
showed the initiative of purse seine fisheries after World War II in 1935.

The Siamese purse seine (official name given by DOF/Thailand) or Uan Lard or Uan
Chon in the Thai language (Fig. 1), was the only type of surrounding net recorded during that
period. Uan Lard was one of the surrounding nets fixed with purse rings and made use of
purse line to close the bottom part of the net. This type of purse seine could be operated in
either daytime or nighttime targeting the Indo-Pacific mackerel and mixed schools of fish
composed mainly of herrings, croakers, threadfins and sting rays that inhabit around the
coastal areas (SEAFDEC, 1986). The operation of Uan Lard could be separated into 2
methods, i.e. (1) single boat method, and (2) two-pair or one-pair method.
(1) Single boat method is operated only in the daytime by employing 7 crew
members. When the fish school is located by the master-fisherman through observation of the
turbid waters caused by the fish school, the crew row the vessel towards the fish school and
the net is dropped around the fish school. When one end of the net is close to another end, a
wooden pole is stuck into the sea bottom. A diver passes both ends of the purse line through 2
snatch blocks at the end of wooden pole. The crew onboard haul the purse line until all rings
got stuck at both blocks, then the crew bring the wooden pole with all purse rings up onboard.
Purse line hauling with wooden pole is used in order to prevent the net bottom from being
lifted from the sea bottom and the fish school from escaping the net circle. When the net
bottom is closed the net panel is manually hauled until reaching the bunt part and the fish is
scooped up and stored into the fish holds.
Fig. 1. Siamese purse seine type I (Uan Lard in Thai): Single boat method
Source: Department of Fisheries of Thailand (1969)
(2) One-pair or Two-pair method is operated while big school of fish is located and
the quantity is observed to be over the capacity of only one net boat, which means that one
piece of net was not enough to surround such big school. Thus, the net radius is expanded to
be double in range in order to completely surround the fish school. The setting position starts
with the two net boats rowing opposite side of each other. The crew from both boats set their
respective net panels by rowing the vessel towards the school followed by shooting the net
around the fish school until reaching the starting end of net that belongs to the other boat
(Fig. 2).

The crew of the net boats stuck their respective wooden poles into the sea bottom.
Each boat has a diver and in the sea bottom, the divers pass the end of both purse lines
belonging to each net boat, passing through 2 snatch blocks at the end of the wooden pole.
The end of the net in the other boat is fastened at the wooden pole in the deck. Then purse
line hauling is carried out as in one boats method facilitated by the divers in order to prevent
being entangled with the net bottom. While all rings got stuck at both blocks, both wooden
poles are in the opposite side position then all purse rings are carried up onboard. The net
panel is hauled by hand until reaching bunt part and fish is scooped and stored in the fish
holds. The other two skiffs assist the net boats during the net hauling operation so that this
method is call one-pair or sometimes two-pair method. This operation could be carried out
both in daytime and night time.
Fig. 2. Siamese purse seine type I (Uan Lard in Thai): Multi-vessel operation
Source: Department of Fisheries of Thailand (1969)
DOF/Thailand (1953) recorded the existence of purse seine without wooden pole,
called the Chinese purse seine type I (Uan Dum or Uan Cha-lorm) operated by one boat. The
Chinese purse seine type I was later renamed as the Thai purse seine by the DOF of Thailand.
Nomura and Yamasaki (1975) cited that Chinese fishermen for Fukien Province of
China introduced the Chinese ring-net in 1926. This Chinese purse seine was a two-boat
purse seine with one large sailing boat (mother boat) and 2 rowing-boats forming a fishing
unit, targeting the mackerel (Ben-Yami, 1994). The DOF/Thailand (1953) had categorized
the Chinese purse seine into Two-boat purse seine and officially named it as Chinese purse
seine type II or Uan Tang-ke in the Thai language. Later, this has been renamed as Chinese
purse seine.
The Chinese purse seine type II or Uan Tang-ke is composed of one large sailing boat
and two rowing boats, and the net is made of cotton yarn treated with a liquid from the
mangrove bark, with Indo-Pacific mackerel as the target catch. This information is very
similar to the report by Boon-lert (1987) which indicated that the Chinese fishers operated the
purse seine using a big sailboat with 2 small skiff boats, targeting the Indo-pacific mackerel.
The introduction of marine engines from Japan in 1935 allowed the Chinese purse
seiners to replace their sailboats with motorized boats, and the first revolution on fisheries of
Thailand was recorded. With the introduction of Nylon netting materials in Thailand in 1954,
the old indigenous surrounding net with wooden purse pole also underwent major
modifications. The poles were no longer used, and the netting was made of black-colored and
later of green-colored nylon. Since 1956, it had been possible to distinguish the so-called
Thai purse seine, whose main catch was also the Indo-Pacific mackerel (SEAFDEC, 1986).
The second revolution of Thai fisheries occurred when the bottom trawl was successfully
promoted from 1960 to 1965. The Thai purse seine fishing was also developed parallel with
the bottom trawl net fishery in accordance with the development of the fishing materials,
fishing techniques and fishing boats during that period.
Fish finders and the echo sounder were introduced to Thai fisheries since 1977 while
the sonar was introduced later in 1980 (Masthawee, 1986). One boat purse seiners had rapidly
increased, conversely decreasing the number of Chinese purse seiners which had
continuously appeared since 1967. Specifically, twelve units were recorded in 1986 and 24
units in 1991 only in the Andaman Sea, and definitely these disappeared from the Gulf of
Thailand since 1992. As for the statistics from 1992 to 2004, there were no records of the
Chinese purse seine operations, nevertheless, few units were observed by the SEAFDEC
during the fishing gear survey in 2004 at the Port of Phuket in the Andaman Sea.
At present, the Thai purse seiners are large vessels of over 100 gross tons with
modern equipment on board such as radar, sonar, echo sounder, fish finder, wireless radio
and power block. On the other hand, the Chinese purse seine had already disappeared from
being used, but in some places in Thailand, it is still possible to find the original type of
surrounding net such as the anchovy and rock-fish surrounding nets at Ban Ao Makhampom
in Rayong Province and in Chumphon Province.
In Thailand, the DOF/Thailand and SEAFDEC distinguished two main groups of
surrounding nets, those with and those without purse line. The nets without purse line are
small and simple, but do not usually appear as a separate category in fishery records.
Surrounding net with a purse line, on the other hand, are large-scale gears whose number has
been increasing annually. The evolution of the purse seine fisheries in Thailand is
summarized in Table 1.

10
Table 1. Evolution of purse seine fisheries in Thailand

Year
Particulars
1926
First record on two-boat purse seine
1935
First official record on Siamese purse seine (purse seine with pole), however the origin period
must have been before this year (based on interview with various persons)
Introduction of marine engine for fishing boats
1947
First official record of the number of Thai purse seiners
1953
First official record of Thai purse seines without pole
1954
Development of netting materials
1955
Statistics on purse seiner officially started
1956
New history of Thai purse seine with netting made of black-colored and later of green-colored
nylon with main catch also the Indo-Pacific mackerel
1957
Statistics of marine catch by purse seine fishing officially started
1960
Development of Trawl fishing
1967
Number of two-boat purse seine starts reducing
1977
Introduction of Echo sounder for fishing operations
1980
Introduction of Sonar for fishing operations
1987
Introduction of tuna purse seiner, R/V Chulabhorn by DOF/Thailand
1992
Official statistics no longer showed the number of two-boat purse seine in Thai fisheries
Introduction of tuna purse seiner, M.V. SEAFDEC by SEAFDEC/TD
1995
Introduction of tuna purse seiner, F.RV. Mahidol by DOF/Thailand
1998
Introduction of tuna purse seiner, F/V Mukmanee by Thai Offshore Fisheries Association
2001
F/V Mukmanee stopped operating because of internal business problems
2.2
Statistics on Thai Purse Seine Fisheries
It has been noted that the official statistics on marine fisheries in Thailand was first
recorded in 1957. Henceforth until 1973, the systematic recording was focused on the total
quantity, quantity by species, quantity of marine products (import-export), and the quantity of
catch by province, region and fishing ground. However, the statistics on the category of
individual of fishing gear were not collected during such period. Meanwhile, the statistics on
marine catch (quantity) by surrounding net fisheries was first compiled in 1974. Monitoring
of the target catches was based on the 4 main categories of purse seine, i.e. (1) purse seine
operated by surrounding the free schooling, (2) purse seine operated by surrounding FAD
(Sung in Thai), (3) two-boat purse seine, and (4) anchovy purse seine.
The statistics on the quantity of catch by purse seine during this period revealed that
the purse seine surrounding FAD accounted for the continuously increasing production year
by year from about 70,000 metric tons in 1974 to 390,000 metric tons in 1983. On the other
hand, production from the purse seine operated by surrounding the free fish schooling had
gradually decreased from 59,000 metric tons in 1974 to 14,000 metric tons in 1983.
11
The statistics also indicated that the catch from two-boat purse seine had obviously
fluctuated from 1974 to 1983. In 1984, the countrys statistical system was reformatted by
grouping the purse seine searching fish schools and surrounding FAD within same category.
Thus, the purse seine fishing gear during this period was classified into 3 categories, i.e. (1)
purse seine, (2) anchovy purse seine, and (3) two-boat purse seine.
It is also noticeable that from 1984 to 2006, the quantity of catch from purse seine
(Fig. 3) had gradually increased from about 400,000 metric tons in 1984 to 770,000 metric
tons in 1995, but it gradually decreased to 530,000 metric tons in 2006. On the other hand,
production of the anchovy purse seine has continuously increased from 87,000 metric tons in
1984 to 150,000 metric tons in 2003 until 2006. It was also observed that the catch from twoboat purse seine disappeared from the statistical records starting in 1986 (Fig. 4).
Fig. 3. Quantity of catch in metric tons, by marine capture and purse seine fisheries (1974-2006)
Source: Department of Fisheries of Thailand (1964-2009)
800,000
700,000
Ordinary
purse seine
Anchovy
purse seine
Chinese Purse
seine
Tuna purse
seine
600,000
500,000
400,000
300,000
200,000
100,000
2006
2002
1998
1994
1990
1986
1982
1978
1974
Fig. 4. Quantity of catch (in metric tons) by type of purse seine (1974 to 2006)

12
It should be considered that in totality, the quantity of catch from the countrys purse
seine fisheries fluctuated from 1974 to year 2006. Although the catch reflected a remarkable
increase from 150,000 metric tons in 1974 to 900,000 metric tons in 1995, after 1995 until
the present, the catch quantity had slightly decreased to 700,000 metric tons in 2006. On the
other hand, it has also been observed that the statistics on the catch from tuna purse seine
fisheries had been recorded separately since 2005, which could be due to the significant
utilization of tuna materials for the tuna canning industry in Thailand. The statistics on
fishing boats and/or fishing units (Fig. 5) had been compiled earlier in 1955 than the statistics
on marine production. In the beginning from 1955 to 1972, the official statistics on purse
seine had been classified into 2 categories, i.e. (1) Siamese purse seine, and (2) Two-boat
purse seine. The data indicated that the number of fishing boats in 1955 was almost equal
between these two categories, i.e. 139 Siamese purse seiners and 175 two-boat purse seiners.
While the number of two-boat purse seiners was mostly constant from 1955 to 1967, the
number of all types of purse seiners rose to 1000 vessels in 1985 and drastically increased to
1600 vessels from 1990 to 1991. From 1962 to 2006, number of one-boat purse seiners had
narrowly fluctuated from 1300 to 1500 fishing vessels.
Fig. 5. Number of purse seiners in Thailand classified by type (1974-2006)

On the other hand, the records also showed that the number of two-boat purse
seiners drastically decreased starting in 1968 and definitely disappeared from official records
in 1992. This could be due to the lack of fisher power and the development of some efficient
hauling devices as well as modern deck machineries. Since 1973, the category of anchovy
purse seine was separated from the ordinary Thai purse seine, which recorded about 103
fishing boats, and since 1984, the number of anchovy purse seiners had been below 100
vessels. However, the number started to increase from 197 in 1985 to 500 fishing boats in
1997 and 2000, but then gradually decreased to 326 in 2006. Over the last decade, it had been
observed that Malaysian anchovy purse seiners had been operating under joint ventures with
Thai fishers in Chumphon and Satun Provinces. In summary, the compilation of statistics on
Thai purse seiners was started in 1955 under the sub-category of Siamese purse seine with

13
175 vessels. The number gradually increased to 500 vessels in 1973 and 1000 vessels in
1987. From 1987 to 2006, number of one-boat purse seiners had been narrowly fluctuating
from 900 to 1000 fishing vessels. The significant fishing ports of the Thai purse seiners are
shown in Fig. 6 while the important fishing grounds both central and lower Gulf of Thailand
are shown in Fig. 7.
Fig. 6 Important fishing ports of Thai purse seiners

Source: SEAFDEC (2004)

14
Central Gulf of Thailand, off the coast of Chumphon Province
Lower Gulf of Thailand, off the coast of Pattani Province

Fig. 7 Important fishing grounds of Thai purse seine fishing in the Gulf of Thailand
Source: Somboon Siriraksophon (2005)

15
3.
Categories of Purse Seines in Thailand
Based on the classification of fishing gear and methods established by FAO, purse
seine is a kind of surrounding net that can enclose the fish schools through a purse line. Some
fishing gears, however, are operated like purse seine nets, e.g. encircling net but the capturing
mechanism could be different in terms of gilling or enmeshing. This had oftentimes made the
people misunderstand that such gear is a kind of gillnet. Hence, encircling net had not been
classified under the surrounding net category. Beach seine and Lampara net is believed to be
one of the origins of purse seine net. More particularly, Lampara net fishing had been
recorded in history as practiced in Egypt since the 14th century. Thus, the beach seine and
Lampara net had been assumed as the origin of surrounding nets without purse line (FAO,
1990). However, since Lampara net was not well-known in Thailand during that period, the
beach seine in combination with the bunt net of bamboo stake traps could be the origin of the
Thai purse seine.
Beach Seine net is a type of fishing gear which had been used in Thailand for a long
time (Fig. 8). Since it is a very simple fishing gear and requires simple method to operate, it
is popularly used by the small-scale fishermen in exploiting the fisheries resources along or
near the shore and targeting the Acetes, shrimps, anchovies, mullet, and other miscellaneous
fishes. Beach seine is an inshore dragnet consisting of two (2) long wing sections which are
assembled by a large mesh-sized net panel and small mesh-sized net at the central of the net
panel, called bunt. If the central part is designed in a pouch-shape or bag-shape, it is called
the bag or pocket part. In bag-less beach seine, the central section is also the deepest part of
the net. The deep beach seine fitted with spring ropes (foot rope hauling line), and operated
offshore can be regarded as a prototype of the ring-net. The same net, if fitted with rings and
purse line, could be regarded as a prototype of a purse seine.
Fig. 8. Beach seine of Thailand

Some fishing gear technologists classified the surrounding net of Thailand under the
ring-net category. This could be due to its design which has been modified from the
combination of the beach seine, Lampara net and the cod-end net of bamboo stake trap.
Notwithstanding, many fisheries institutes in Thailand, the Department of Fisheries of
Thailand and the Southeast Asian Fisheries Development Center/Training Department
(SEAFDEC/TD) had named the Thai surrounding net as purse seine net and not as a ring net.

16
The classification of purse seine under the DOF/Thailand system is different from the
SEAFDEC/TD system. The DOF/Thailand classified the purse seine by mesh size as had
been stipulated under the countrys fisheries regulations. The classification by mesh size also
reflects the target catch as well. On the other hand, SEAFDEC/TD classified the type of purse
seine based on a different system which is more related to the category of the statistics
compiled during the period from 1970 to 1980. Thus, SEAFDEC/TD classified the purse
seines by taking into consideration three (3) main prominent characters, i.e. (1) target catch,
(2) characteristics of the net, and (3) mechanism of the fishing techniques.
The descriptions by DOF/Thailand and SEAFDEC/TD are described in this part of the
document. The classification by DOF/Thailand was based on the Definition and
Classification of Fishing Gear in Thailand (DOF, 1994), while the SEAFDEC/TD
classification was derived from Fishing Gear and Methods in Southeast Asia I: Thailand
(SEAFDEC, 2004).
3.1
Categories of Surrounding Nets Classified by the Department of Fisheries of

Thailand
3.1.1 Surrounding nets without a purse line

The simplest gears in terms of construction and in the method of operations are the
surrounding nets without a purse line. These gears have traditionally been used by smallscale fishers operating in coastal waters for catching anchovies, rocky fishes and other nearshore species. Before, this kind of surrounding net was rarely employed by the Thai fishers
because of the lack of divers. Thus, there were only less than 20 fishing boats operating this
type of gear. Nowadays, this kind of surrounding net had been modified by using a purse line.
Surrounding nets without purse line are classified into two (2) main types, i.e. 1) surrounding
nets without a purse line (mesh size less than 10 mm), and 2) surrounding nets without a
purse line (mesh size larger than 10 mm).
3.1.1 (1) Surrounding nets without a purse line (mesh size less than 10 mm)
This type of surrounding net is called Uan glud ta-khaw in Thai. It is usually operated
from a small boat (8-14 meters length, 6-150 HP engine) by 6-10 fishermen. The net is
rectangular in shape, 200-400 m in length and 10-15 m in depth. The main net consists of
6.4x6.4 to 7.4x7.4 mm nylon minnow net or 5.5 to 8.3 mm raschel net. Polyethylene 250 d/12
netting is used for the lower selvedge. The float line is longer than the sinker line, and the
buoyancy force is about double that of the sinking force. The ground rope is fixed with 200 g
lead at intervals of 50 cm. While no purse line is assembled with the net, 30 pieces C-shaped
steel hooks of 9 cm length are used to close the bottom part of the net. The only other piece
of equipment onboard apart from the net is an air compressor to supply air to the fisherman
who dives when the bottom of the net has to be closed.

17
The main target species are anchovies and planktonic shrimps, but some by-catch
such as the predators that feed on anchovies could also be caught. This gear is operated in
fishing grounds that are sandy or muddy and sandy, the most common characteristics of the
waters in Rayong, Chantaburi and Trat Provinces.
3.1.1 (2)
Surrounding nets without a purse line (mesh size larger than 10 mm)
This type of surrounding net is called Uan lom lung hin in Thai. It is usually operated
from a small boat (8-14 meters length, 6-150 HP engine) by 6-10 fishermen. This net is able
to surround an underwater rocky area or coral area. In view of the countrys limited fishing
grounds, this kind of net is not widely used in Thailand.
Since this net was modified from the anchovy surrounding net, the fishing method is
almost same although there are some differences in terms of the net materials and the choice
of the suitable fishing grounds. This purse seine net is rectangular in shape, 250-300 m in
length and 10-20 m in depth. The mesh size of the main net is 25 mm. Nylon 210 d/6 is used
for the main net while 30 mm polyethylene net 380 d/12 is used for the selvedge. The float
line is longer than the sinker line, and buoyancy force is about double than that of the sinking
force. The ground rope is fixed with 200 g lead at intervals of 100 cm. Although no purse line
is assembled with the net, 30-40 pieces of C-shaped steel hooks 7 cm in length are used to
clip for closing the bottom part of the net (Fig. 9 and Fig. 10). As in the previous purse seine,
the only piece of equipment onboard apart from the net is an air compressor to supply air to
the fisherman who dives when the bottom of the net needs to be closed.
The fishing grounds for this purse seine should have rocky bottom or around a reef.
The main target species are the yellow-tail fusiliers, rabbit fish, cavalla, barracuda and other
coral fishes. This gear is commonly found in the eastern part of the Gulf of Thailand,
especially in Makhampom Bay in Rayong Province.
3.1.2 Surrounding nets with a purse line
The information in the countrys fisheries statistical record indicated that there were
840 registered purse seiners in 1982, most of which were categorized into 10-100 gross
tonnage, and used luring devices such as fish aggregating devices (FADs) and light. Some
purse seiners had been equipped with modern equipments onboard, such as wireless set radio
communication, echo-sounder, sonar, and radar. In 1985, some boats were even installed with
satellite navigation system that made fishing ground has been precisely recorded. Many
auxiliary fishing gears and hauling devices are also used onboard, i.e. capstan winch
(mechanical of hydraulic), davit pulley, boom crane, electric generator, fish luring lamps and
power block. Usually however, there are no freezers onboard, so wet or dry ice is used
instead to preserve the catch. This method of fishing would necessitate a rather large
manpower requirement, which may in time, become a disadvantage. There are five main
kinds of surrounding nets with a purse line and respective mesh sizes classified under this
category.
18
Fig. 9. Surrounding net without a purse line (mesh size larger than 10 mm)

19
Fig. 10. Fishing operation of surrounding net without purse line (mesh size larger than 10 mm)
3.1.2 (1)
Surrounding nets with a purse line (mesh size less than 10 mm)
In the Thai language, this type of surrounding net is called by various names, i.e. Uan
lom chub pla katak or Uan lom chub pla jing-jung or Uan lom chub pla hau-on. The net
construction is similar to that of the anchovy surrounding net without purse line except that a
purse ring is attached to the sinker line, hence the bottom of the net can be closed with the
purse line (Fig. 12). It is usually operated from a small boat (10-22 m in length, 20-300 HP
engine) by 6-30 fishermen.

20
The fishing boat is usually installed with a fish finder, GPS and radio transceiver. The
fishing grounds are reported to be around Trad, Rayong, Chumphon, Surat-Thani and Satun
Provinces. Some fishing boats, particularly those operating around Chumphon, Surat Thani
and Satun Province, had been introduced from Malaysia (Fig. 13) and installed with boilers
for dry preservation and processing of the catch onboard.
Fig. 11. Surrounding net with a purse line (mesh size less than 10 mm)

21
Fig. 12. Fishing operation of surrounding net with a purse line (mesh size less than 10 mm)
The net is rectangular in shape, 250-450 m in length and 15-80 m in depth. The float
line is shorter than the sinker line (hanging ratio (E) = 0.83/E=0.93). The main net is blue
polyethylene minnow net 2 x 2 mm and/or green nylon raschel net 4.0-8.3 mm mesh size and
the size of the twine is 110 d - 210 d/5. Polyethylene net, twine size 380 d/12-15 and 25 mm
mesh size, is used for selvedge at the sinker line. Iron purse rings, diameter 10-15 mm, are
attached on the sinker line with 2-3 kg lead at intervals of 1.5 to 3.0 meters. A polyethylene
cross-rope, 26-40 mm diameter, is used for the purse line. Buoyancy force is about twice that
of the sinking power (Fig. 11).

22
Fig. 13. Purse seiner of surrounding net with a purse line (mesh size less than 10 mm)
Left: Thai model; Right: Malaysian model
Photo by SEAFDEC (2004) and A. Munprasit (2009)
Fishing methods of this gear are classified into two (2) main categories, i.e. (1) fishing
operation without luring light, and (2) fishing operation with luring light, and mainly
targeting the various species of anchovies. By-catch including other pelagic fishes and squids
attracted by the luring lights are also caught. Anchovy purse seine can be found in the east
coast of the Gulf of Thailand (Rayong, Chantaburi, and Trat), in the southern east coast
(Surat Thani), and in the southern part of the west coast of Thailand, especially in Phuket,
Krabi and Satun.
3.1.2 (2)
Surrounding nets with a purse line (mesh size 10.0-24.9 mm)
This type of surrounding net is called Uan lom loog-mha (Puppy Purse seine), Uan
lom muk, Uam lom hang-yoa and Uan lom ta-kieng in Thai. The fishing boat used is smallscale with an inboard or outboard engine. The fishing operation is able to conduct both
searching for fish schools and use of luring lights (Fig. 14). The gear is usually operated from
a small boat (9-14 m in length with 24-150 HP inboard engine or 10 HP outboard engine) by
4-20 fishermen. The fishing boat is installed with fish finder, GPS, radio transceiver and
luring raft.
The net is rectangular, 100-400 m in length and 14-40 m in depth. The main net is
green or black nylon net, mesh size 16-20 mm. Polyethylene net, twine size 380 d/12-15 and
mesh size 25 mm, is used for selvedge at sinker line. Iron purse rings, 10-15 mm diameter,
are attached on the sinker line with lead having a total weight of 0.5-2.0 kg/piece. Twistedrope, 16-28 mm diameter is used for the purse line (Fig. 15). The fishing method can be
classified into: (1) fishing operation without luring lights, and (2) fishing operation with
luring lights. The operational procedure is the same as that of the other surrounding nets with
purse line. Most purse seiners, however, are not equipped with any hauling devices. The
principal target species are the Indo-Pacific mackerel, scads and squids. By-catch such as
pony fish and other juvenile fishes are also caught. Surrounding nets with purse line with
mesh size between 10.0-24.9 mm are mostly found in Chumphon Province.

23
Fig. 14. Luring light boats at a fishing port in

Rayong Province
3.1.2 (3)
Fig. 15. Purse seiner of surrounding net with a purse line

(mesh size 10.0-24.9 mm)
Photo by SEAFDEC (2004)
Surrounding nets with a purse line (mesh size 25.0-29.9 mm)
This type of surrounding net is called in Thai as Uan dum and Uan lom sung and Uan
tang-ke (two-boat purse seine), and is widely used in the Gulf of Thailand and the Andaman
Sea (Fig. 16). The net construction is similar for the Uan dum and Uan lom Sung types
except for Uan tang-ke (two-boat purse seine). Nowadays, large vessels are already equipped
with sonar and echo sounder for detecting schools of fish. In the past and even today in the
case of small vessels, a fish school has to be spotted by ocular inspection at twilight time.
Sometimes, however, Thai purse seines are operated with fish luring lights and fish shelters
(FADs), which causes some difficulties and confusion in the compilation of the
corresponding fishery statistical data.
Purse seine is usually operated from a medium-scale boat (14-26 m in length, 20-700
HP engine) by 10-30 fishermen. A net hauler is always installed on the port side. One or two
luring light boats or lighted rafts and one skiff boat to serve as a luring boat usually make a
fleet complete. Special two skiff boats are used for the operation of Uan tang-ke (two-boat
purse seine) which is different in terms fishing techniques although with the same mesh size.
The net of Uan dam is rectangular but the length varies, i.e. usually 400-600 m for
luring light operation and 800-1800 m for free schooling operation (Fig. 17 and Fig. 18), 60110 m in depth and the cod end is assembled at the middle of the net. The main net is made of
black-colored nylon net with 25 mm mesh size and twine size of 210d/9-12. The float line is
shorter than the sinker line (E = 0.6-0.7/E=0.65-0.75). The bunt part is Polyethylene net twine
380d/18 in size with 25.0 mm mesh size. The buoyancy force is 1.3-2 times higher than the
sinking power. Polyethylene cross-rope, diameter 26-40 mm is used for the purse line.

24
Fig. 16. Purse seiner of surrounding net with a purse line (mesh size 25.0-29.9 mm)
Uan dam has mesh size 25.0 to 29.9 mm which is operated by different luring
methods (Fig. 19) and also with different float line lengths. Uan dam operated by luring light
lamp has the shortest float line, however Uan dam operated by sonar searching has the
longest float line and the deepest compared with the other two luring methods where the fish
schools are aggregated by light (Fig. 20) or FADs (Fig. 21 and Fig. 22), but are less active
than the free swimming fish schools. The principal target species largely consist of IndoPacific mackerel and scads. The fishing grounds are in the eastern and western parts of the
Gulf of Thailand, in the inner Gulf, and the southern part of the Andaman Sea. The main
ports are located in Samut Sakhon, Chonburi, Langsuan (Chumphon Province) and Kantang
district (Trang Province).

25
Fig. 17 Surrounding net with a purse line (mesh size 25.0-29.9 mm): Free schooling surrounding method

26
Fig. 18 Fishing operation of surrounding net with a purse line (mesh size 25.0-29.9 mm): Free schooling surrounding method
by visual searching

27
Fig. 19 Surrounding net with a purse line (mesh size 25.0-29.9 mm): Luring light surrounding method

28
Fig. 20. Fishing operation of surrounding net with a purse line (mesh size 25.0-29.9 mm): Luring light surrounding method

29
Fig. 21. Surrounding net with a purse line (mesh size between 25.0-29.9 mm): FAD surrounding method

30
Fig. 22. Fishing operation of surrounding net with purse line (mesh size 25.0-29.9 mm): FAD surrounding
method
Apart from Uan dum and Uan lom sung, several vessels are required for the operation
of Uan tang-ke. The mother boat is 16-20 m long, wooden vessel with a 100-250 HP main
engine (Fig. 25). Two rowing-boats (8x2x0.8 m) are used as net boats, and another rowing
boat also participates during the fishing operation. The net is rectangular, 350 x 60 m, made
of black-colored nylon net, 25 mm mesh size and twine size is 210 d/9-12. Polyethylene, 25
31
mm, 380d/15, is used for the top and bottom selvedge net. The float line is shorter than the
sinker line (E = 0.8/E=0.93).
The bunt part is nylon net, 25 mm mesh size and twine size is 210d/12. Two purse
lines, polyethylene cross-rope, diameter 28-32 mm, are assembled at the middle of the net.
The main target species are scads, barracuda, cavalla, trevally, Spanish mackerel, mackerel,
and bonito. The fishing grounds are along the Andaman Sea coasts of Phuket, Trang, and
Satun Provinces.
Fig. 23. Two-boat purse seine (Uan Tang-ke)

Source: SEAFDEC/TD (1986)

32
Fig. 24. Fishing operation of two-boat purse seine (Uan Tang-ke)

Source: SEAFDEC/T (1986)
Fig. 25. Two-boats purse seiner

Left: Mother boat
Right: Rowing boats
Photo by SEAFDEC (2004)

33
3.1.2 (4)
Surrounding nets with a purse line (mesh size between 30.0-45.0 mm)
This kind of surrounding net makes use of sonar to detect the fish schools. The purse
seine is usually operated from a medium-scale boat (10-20 m in length, 24-300 HP engine) by
10-30 fishermen. A net hauler is always installed on the port side, and the operation is mostly
conducted by surrounding the free schooling fish.
The purse seine net is 400-800 m in length and 40-80 m in depth. The main net has
38-42 mm mesh-size, the material is black and green nylon net, twine size is 210 d/12-24
and cod-end is polyethylene with twine size 380 d/9-36 based on the target species. The float
line is shorter than the sinker line (E=0.7-0.9/E=0.75-0.9). The ratio between the depth and
the length of net is 1/5-1/7. The ground rope is attached with iron purse rings and sinker with
a total weight of 2-3 kg/point. Polyethylene cross-rope, diameter 20-30 mm is used for the
purse line (Fig. 26 and Fig. 27).
The main target species largely consist of big size Indo-Pacific mackerel, hardtail
scads, pomfrets, little tuna, and bonito. The fishing grounds are in the central Gulf of
Thailand, while the main fishing ports are located in Samut-Sakorn, Samut-Songkram,
Prachaub-kirikarn, Rayong, Songkhla and Pattani Provinces.
3.1.2 (5)
Surrounding nets with a purse line (mesh size larger than 45.0 mm)
This is one of the largest purse seines in Thailand which was developed for catching
bonito in the Gulf of Thailand. The purse seine is usually operated from a medium-scale boat
(20-32 m in length, 300-520 HP engine) by 30-45 fishermen. A net hauler is always installed
on the port side. The operation is mostly conducted by surrounding the free schooling fish
both at daytime and nighttime by visual and sonar searching methods (Fig. 28).
The purse seine net is from 800 to 1800 m in length and 100-120 m in depth. The
main net has 47-100 mm mesh-size, the material is black and green nylon 210 d/12-36 and
210/18 mixed with Saran and polyethylene 380 d/18-36 with 25 mm mesh size at the codend. The float line is shorter than the sinker line (E=0.7/E=0.75). The ratio between the depth
and the length of net is 1/5-1/7. The ground rope is attached with iron purse rings and sinker,
the total weight is 2-3 kg/point. Polyethylene cross-rope, diameter 38-40 mm is used for the
purse line.
Fish schools are detected by sonar. Fishing is done at twilight and nighttime mainly
targeting eastern little tuna, bonito, skipjack, hardtail and scads. The fishing grounds are in
the central Gulf of Thailand, South China Sea and Andaman Sea including Myanmar waters.
The main fishing ports are located in Samut-Sakorn, Samut-Songkram, Prachaub-kirikarn,
Rayong, Songkhla, Pattani, Ranong, and Phuket Provinces.

34
Fig. 26. Surrounding net with a purse line (mesh size 30-45 mm)

35
Fig. 27. Surrounding net with a purse line II (mesh size 30-45 mm)
Source: SEAFDEC 1986

36
Fig. 28. Fishing operation of surrounding net with purse line: free-schooling search by hydro-acoustic equipment
3.2
Categories of Surrounding Nets Classified by SEAFDEC/TD
SEAFDEC/TD had classified the types of purse seines with different system which is
more related to the statistics compiled during period from 1970 to 1980. Thus,
SEAFDEC/TD classified the purse seine categories considering 3 main prominent
characteristics, i.e. (1) target catch, (2) characteristic of net, and (3) mechanism of the fishing
techniques.

37
3.2.1 Surrounding nets without a purse line

Details of the fishing gear and methods are the same as the category of surrounding
nets classified by DOF/Thailand (3.1).
3.2.1 (1)
Anchovy surrounding net (Uan Glud Takhao)
nets without a purse line (mesh size smaller than 10 mm) classified by DOF/Thailand
(3.1.1 (1)).
3.2.1 (2)
Rock-fish surrounding net (Uan Lom Lung Hin)
Details of the fishing gear and methods are the as the category of surrounding nets
without a purse line (mesh size larger than 10 mm) classified by DOF/Thailand (3.1.1 (2)).
3.2.2 Surrounding nets with a purse line or purse seines
SEAFDEC/TD classified the surrounding nets with purse line into 6 models based on
the target species, characteristics of the catch, fishing net and luring techniques. In some
cases, this had caused confusion on the category as it could be considered as some kind of
surrounding net, e.g. Thai purse seine (Uan dum) and Luring purse seine (Uan Sung and Uan
Ta-geang) or Bonito purse seine (Uan lon pla-o) and Luring purse seine (Uan Sung and Uan
Ta-geang).
3.2.2 (1)
Chinese or two-boat purse seine (Uan Tang-Ke)
with a purse line (mesh size between 25.0-29.9 mm), and partial information of Chinese or
two-boat purse seine (Uan tang-ke) as classified by DOF/Thailand (3.1.2 (3)).
3.2.2 (2)
Anchovy purse seine (Uan Lom Chub Pla Katak)
nets with a purse line (mesh size smaller than 10.0 mm) as classified by DOF/Thailand
(3.1.2 (1)).
3.2.2 (3)
Thai purse seine (Uan Dum)
with a purse line (mesh size 25.0-29.9 mm, 30.0-45.0 mm and larger than 45.0 mm) as
classified by DOF/Thailand (3.1.2 (3), 3.1.2 (4), 3.1.2 (5)).

38
3.2.2 (4)
Luring purse seine (Uan Sung and Uan Tageang)
with a purse line (mesh size 25.0-29.9 mm, 30.0-45.0 mm and larger than 45.0 mm) as
classified by DOF/Thailand (3.1.2 (3), 3.1.2 (4), 3.1.2 (5)).
3.2.2 (5)
Bonito purse seine (Uan Lom Pla-o)
with a purse line (mesh size larger than 45.0 mm) as classified by DOF/Thailand (3.1.2 (5)).
3.2.2 (6)
American tuna purse seine (Uan Lom Pla Too-na)
For fifteen years (1982-1997), the most advance Thai fishing gear was the Tuna purse
seine on the Super Seiner. In 1987, the Department of Fisheries of Thailand acquired one
large fisheries research vessel, the R.V. Chulabhorn from Hayashikane Dockyard of Japan.
Although the vessel was basically constructed as a trawler, the design was meant for
multipurpose uses, i.e. stern trawler, pelagic & bottom longliner, gillnetter and purse seiner.
In 1994, The Southeast Asian Fisheries Development Center/Training Department

(SEAFDEC/TD) also acquired a multipurpose fishery research and training vessel, the M.V.
SEAFDEC from Miho Dockyard of Japan. It was basically constructed is a tuna purse seiner
(Super Seiner), however she was also concurrently designed to function as longliner and
gillnetter as well as for pot during certain cruises at some period of time.
Moreover in 1995, the Department of Fisheries, Thailand constructed a new Tuna
Fisheries Research Vessel, the R.V. Mahidol through the Hayashikane Dockyard in Japan. A
1270 gross tonnage vessel, she was designed for an American tuna purse seine class being a
typical type tuna purse seiner. Then in 1999, the Thai Offshore Fisheries Association has
employed a typical tuna purse seiner, the M.V. Mukmanee, about 990 gross tonnage used as a
purse seiner. Her original name and owner was Tokiwa Maru No.1, from Taiyo Fisheries of
Japan, respectively.
Most of the abovementioned vessels are mainly operated in the Indian Ocean and
rarely in the Andaman Sea because of the latters current condition which always changes in
terms of direction and velocity, thus American type tuna purse seining operation is not
possible. Although the M.V Mukmanee had operated in the Eastern Indian Ocean from
November 1998 to June 2001 (Praulai et al., 2002), it had stopped its operations because of
some business losses on the part of the operator and was reported to have been sold later to a
Philippine company. Furthermore, the R.V. Chulabhorn has also stopped its operation in tuna
purse seine fishing and at present, its functions include longline and deep sea pot fishing as
well as in oceanographic surveys.

39
The fishing nets employed during the fishing trials of the aforementioned vessels vary
in length from 1000 to 2000 m and in depth from 250 to 300 m The mesh size is 90 mm at the
bunt part and 210 mm at the body and wing, and operated with fish aggregating devices
(FADs) or Payao as it is called in the Philippines. The main target species are skipjack,
yellowfin tuna, and bigeye tuna while the by-catch could include the rainbow runner, horse
mackerel, dolphin fish, and leather-jacket.
3.3 Categories of Surrounding Nets Classified by FAO (ISSCFG)
In 1971, the FAO adopted the International Standard Statistical Classification of
Fishing Gear (ISSCFG), where the sequence and numbering of the gear categories
correspond to the numerical code used by the ISSCFG. The numerical code was adopted
during 10th session of the Coordinating Working Party of Atlantic Fisheries Statistics in
Madrid in July 1980.
The description of surrounding net established by Claude N. and J Prodo (1990)
indicated that the net could catch fishes by surrounding them from both sides and from
underneath, thus preventing them from escaping in the deep waters by swimming
downwards. Moreover, they also considered the surrounding net as surface net where the
float line is supported by numerous floats. As shown in Fig. 29, FAO classified surrounding
nets into two (2) main categories, i.e. Surrounding net with purse line (Purse Seines) and
Surrounding net without purse line (Lampara Nets). The summary of the classifications of
surroundings nets by DOF/Thailand and SEAFDEC/TD are also shown in Fig. 30 and Fig.
31, respectively. Moreover, the comparison of the classifications by FAO, DOF/Thailand and
SEAFDEC/TD is shown in detail in Table 2.
3.3.1 Surrounding net with purse line (Purse seines)
The net under this category is a purse seine characterized by the use of a purse line at
the bottom of the net (Table 3 and Table 4). The purse line enables the net to be closed like a
purse and thus retain all the fishes that are caught in the net.
Purse seines (Standard Abbreviation: PS) could be very large and operated by one
boat (Standard Abbreviation: PS1) or two boats (Standard Abbreviation: PS2). In most usual
cases, a purse seine is operated by a single boat with or without auxiliary skiff.
3.3.2 Surrounding net without purse line (Lampara Nets)
The Lampara net is the type most represents this category. Its particular design shows
the central bunt in the form of a spoon and two lateral wings, making it possible to retain a
school of fish when the two wings are hauled up at the same time. Lampara net is generally
operated by a single boat, usually of small tonnage (Table 4). The Standard Abbreviation of
Lampara net is LA.

40
Surrounding net
Surrounding net with Purse Lines

(Purse seine, Ring net)
Surrounding net without purse line
(Lampara net)
Fig. 29.Categories of surrounding nets classified by FAO

Source: FAO (1990)
Purse seine
(Thai name: Uan Lom)
Surrounding net with purse line
Mesh size smaller than 10 mm

Target catch: anchovy and sardines
Mesh size between 10.0 to 24.9 mm
Target catch: Chub mackerel, sardines, caranx
and pony fish
Target catch: Chub mackerel, Indian mackerel,
caranx, sardines, pomfret, and bonito
caranx and hardtail scad
Mesh size larger than 45.0 mm
Target catch: Tuna, skipjack, bonito, little tuna
Mesh size smaller than 10 mm

Target catch: anchovy
Mesh size larger than 10 mm
Target catch: rock fishes
Fig. 30. Categories of Thai surrounding nets classified by the Department of Fisheries of Thailand
Source: DOF/Thailand (1997)

41
Surrounding netwith purse line

(Thai name: Uan Lom)
One-boat purse seine
Luring purse seine (light)

(Thai name: Uan Tageang)
caranx and hardtail scad
Luring purse seine (shelter)
(Thai name: Uan Sang)
Target Catch: Chub mackerel, Indian mackerel, caranx,
hardtail scad, pomfret, spanish mackerel and bonito
Ordinary purse seine
(Thai name: Uan dum or Uan Lom)
Target Catch: Chub mackerel, Indian mackerel, caranx,
hardtail scad and bonito
Anchovy purse seine
(Thai name: Uan Lom Pla Ka-tak)
Target catch: anchovy and sardines
American purse sine
(Thai name: Uan Lom Pla Too-na)
Target catch: Tuna, skipjack, bonito, little tuna
Two-boat purse seine
Chinese purse seine

(Thai name: Uan Tang-ke)
Target catch: Chub mackerel, Indian
mackerel, caranx and hardtail scad
(Thai name: Uan Glud Takhao, Uan Lom Lung Hin)
Target Catch: rock fishes, anchovy and sardines
Fig. 31. Categories of Thai Surrounding nets classified by SEAFDEC/TD

Source: SEAFDEC/TD (2004)
Table 2. Comparison of the categories of surrounding nets

FAO Category
SEAFDEC Category
One-boat purse seine
Surrounding net with

purse line (Purse seine,
Ring net)
Surrounding net without

purse line ( Lampara net)
Anchovy purse seine

Uan Lom Pla Ka-tak
Luring light purse seine
Uan Tageang
DOF/Thailand Category
Mesh size smaller than 10.0 mm
Mesh size between 10-24.9 mm
Fish shelter purse seine

Mesh size between 25.0-29.9 mm
Uan Sang
Ordinary purse seine
Mesh size between 30.0-45.0 mm
Uan dum or Uan Lom
Americal purse seine
Mesh size bigger than 45.0 mm
Uan Lom Pla Too-na
Two-boat purse seine
Chinese purse seine (Mesh size between 25.0 mm)
Uan Tang-ke
Mesh size smaller than 10.0 mm
Surrounding net without purse line (One-boat)
Uan Glud Takhao
Uan Glud Takha or Uan Lom Lung Hin
Mesh size bigger than 10.0 mm
Uan Lom Lung Hin

42
Table 3. Comparison of the types of surrounding nets with and without purse line
Types of
Surrounding nets
Without purse line

Anchovy
Rock fishes
With purse line

Chinese purse
seine
Anchovy
Mackerel,
Caranx,
sardines
Mackerel,
Caranx,
sardines
Mackerel,
Caranx,
sardines
Luring light
Searching
Luring light
FADs
All
technique
Luring technique
Searching
Length of fishing boats
14 m
10 m
18 and 8 (2) m
17.5 m
15 m
20 m
28 m
Main engine (HP)
180
10
230
150
150
240
520
Net Structure
Bunt at net
center
(1530 m)
Bunt at net
center
Bunt at net
center
Bunt at net
center
Bunt at net
center
Bunt at net
center
Bunt at wing
part
Length of net float line
300 m
240 m
360 m
400 m
420 m
665 m
1197 m
Length of sinker line
290 m
240 m
420 m
384 m
480 m
713 m
1283 m
Approx. depth of net
15 m
Shrinkage of Float line
0.85
0.65
0.80
0.83
0.70
0.70
0.70
Shrinkage of Sinker line
0.83
0.65
0.93
0.80
0.80
0.75
0.75
Mesh size
Bunt (mm)
6 6 mm
25 mm
25 mm
5.55.5 mm
25 mm
25 mm
25 mm
Net body
7 7 mm
25 mm
25 mm
7.47.4 mm
25 mm
25 mm
25 mm
Selvage
45 mm
25 mm
25 mm
45 mm
31, 62.5 mm
25, 57 mm
40 mm
Bunt
PA 210/6,8
PE 380d/12
PA 210d/12
PA 210d/6,8
PE 380d/15
PE 380d/18
PA 210d/30
Net body
PA 210/4, 6
PA 210d//6
PA 210d/9
PA 210/4, 6
PA 210d/3, 6, 12
PA 210d/9, 12
Selvage
PE 250/12
PE 380d/9,12
PE 380d/15
PE 250d/12
PE 380d/15
PE 380d/18
PE 400d/18
Total float in number
185+925
370
360
1620
1315+264
1918+256
3990
Total float in buoyancy
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Total sinker in number
580
241
420
81
190+53
188+96
334
Total sinker in weight
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Material
N/A: Not avialable

43
Table 4. Techniques adopted in fishing with surrounding nets (with purse line) with the
corresponding main target species
Type of Surrounding
net
With purse line

Mackerel, Carang, Bonito, little tuna,
sardine s
hardtail scad
Bonito, little
tuna, pomfret
Bonit, little tuna,

hardtail scad
Bonit, little tuna,

hardtail scad
Skipjack, tuna
Luring technique
Searching
All technique
FADs
All technique
Searching
FADs
Length of fishing boat
19.5 m
30 m
15 m
28 m
32 m
65 m
Main engine (HP)
185
350
240
460
400
2800
Net Structure
Bunt is at net
center, size
Bunt is at net
center, size
Bunt is at net
center, size
Bunt is at net
center, size
Bunt is at net
center, size
Bunt at the wing part
Length of net Float line
592 m
1009 m
810 m
1610 m
1729 m
1266 m
Length of Sinker line
625 m
1116 m
810 m
1728 m
1853 m
1440 m
Shrinkage of Float line
0.60
0.70
0.90
0.70
0.70
0.74
Shrinkage of Sinker line
0.64
0.75
0.90
0.75
0.75
0.84
Mesh size
Bunt
25 mm
43.8 mm
50 mm
50 mm
50 mm
90 mm
Net body
44 mm
43.8 mm
50 mm
50, 98 mm
50, 98 mm
60, 90, 105, 210 mm
Selvage
40 mm
50 mm
25, 50 mm
57 mm
57 mm
150 mm
Bunt
PA 210d/ 15
PE 380d/ 18
PA 210d/ 9
PA 210d/ 36
PA 210d/ 36
PA 210d / 180, 224
Net body
PA 210d/ 9, 12
PA 210d/12, 18, 24
PA 210d/ 6
PA 210d/18, 21
PA 210d/18, 21
PA210d/ 18 + SN
PA210d/ 18 + SN
PA 210d/ 40, 60, 90,

120 T 250d/ 210
Approx. depth of net
Material
PE 380d/ 15
PE 380d/ 21
PE 380d/ 12
PE 380d/ 18
PE 380d/ 18
PE UC 320ply
Total float in number
1920+250
2754+697
1620
2648+674
5160+590+960
N/A
Total float in buoyancy
N/A
N/A
N/A
N/A
N/A
N/A
Total sinker in number
160+91
160+320+240
81
1204+344
396+134
N/A
Total sinker in weight
N/A
N/A
N/A
N/A
N/A
N/A
Selvage

44
4.
Principles of Thai Purse Seine Fishing Operations
4.1
Surrounding nets without a purse line
Surrounding net without purse line is always operated near shore in the daytime, in
the early morning and evening, where the water depth is 2-10 m. The mesh size of the net is
less than 10 mm, and the targeted fish school is located by simple visual search. Setting and
hauling is operated at starboard side of the boat. During hauling operation, an anchor must be
dropped into the sea bottom to fix position of the boat and prevent it from drifting into the net
circle, and 1-2 fishermen dive underwater and clip the bottom part of the net using the Cshape steel hook, starting from the net part near fishing boat (Fig. 10). Each C-shape steel
hook is set at 2-3 m interval. The crew then hauls the purse seine net at the starboard until
reaching the bunt part at the center of the net.
4.2
Surrounding nets with a purse line (mesh size less than 10 mm)
The fishing methods for the purse seine with mesh size less than 10 mm, targeting
mainly the anchovies are classified into two (2) main operations, i.e. without using luring
light and with luring light.
4.2.1 Fishing operation without luring light
Fishing operation using surrounding net without luring light, is always conducted in
the early morning or evening. The fish schools are located by ocular sighting or by using the
fish finder. The fishing net is released while the fishing master finds the school of fish. The
purse line is hauled to close the bottom part of the net. In Rayong Province (Fig. 14), the
fishing vessels are normally is less than 14 m in length having special wooden pole fixed with
2 iron purse rings, which is 15 cm in diameter at the tip of the pole. The tip of pole with 2
purse rings are put underwater at depth of 7-8 m and passing the purse line through the 2
rings. This is meant to reduce the gap at the foredeck prevent the fish from escaping. Some
larger purse seiners, however, usually drop 1-2 pieces of sinkers weighing about 50 kg for
closing the net opening/gap at the foredeck. After hauling the purse line, net body is hauled
by manually or with the use of a net hauler at both sides, i.e. starboard and port side of the
fishing boat (Fig. 17 and Fig. 18). One to five fishing operations can be done within a day.
4.2.2 Fishing operation with luring light
For surrounding net with luring light (Fig. 19 and Fig. 20), the fishing operation is
always operated at nighttime, usually starting in the evening by searching for fish schools.
Nowadays, three luring boats are anchored to light the location where some fish schools are
detected or sometimes the luring lights are set near the FADs. Luring light period would last
for at least 2 hours. Recently, underwater lamps are used during the purse seine operation,

45
which is meant not only for attracting fish schools but also for preventing the fish schools
from escaping from the net circle.
The fishing operation could be started while the quantity of fish in the school is
adequate for surrounding. The anchor of the light boat is hauled up and shooting operation is
started by surrounding the light boat. While the purse line is hauled, the light boat leaves the
net circle by pushing the float underwater and passing across the float line. The remaining
process is the same as the operation in daytime.
4.3
Thai Purse seine
Surrounding operations of purse seine with a purse line with mesh size greater than 25
mm, can classified with three (3) main methods, i.e. surrounding the free schooling fishes,
surrounding with the use of luring light, and surrounding by means of FADs.
4.3.1 Surrounding free fish schooling
Fish schools are located by visual searching or using the fish finder. The fishing net is
released while fishing master finds the fish schools. The purse line is hauled to close the
bottom part. The net is hauled manually or using a net hauler on both sides of the vessel. In
case of Uan tang-ke (two-boat purse seine), the fishing operation is conducted from a single
boat (Fig. 24 and Fig. 25). The net is hauled by hand on both sides of the boat, while the
purse line is pulled by a capstan winch driven by the main engine of the vessel.
Masthawee (1986) described the operation of ordinary Thai purse seine with
traditional searching technique for the fish schools which could be conducted at daytime and
nighttime. When the purse seiner arrive the fishing ground, two (2) main fish school detection
methods could be adopted, i.e. 1) visual or 2) using hydro-acoustic equipment. In case of the
visual detection method, fishing operation could be started while fish schools had already
been located (Fig. 18). On the other hand, the searching process using hydro-acoustic method
is little bit different (Fig. 28). The fishing vessel must be controlled with limited speed during
the hydro-acoustic sighting based on the data from the sonar dome installed below the hull of
the vessel. If the master fisherman could locate the fish school, a marked buoy or light raft is
set at the location of the targeted school and the circle net is dropped as the remaining part of
the fishing operation of a Thai purse seine as shown above is conducted.
After detecting a large fish school either visually or through the hydro-acoustic
equipment, the master fisherman must check the other environmental conditions, e.g. wind
speed and direction, current speed and direction, swimming speed and direction of the fish
school, sea depth as well as the characteristics of the sea bottom. The arrangement of the
crew for the fishing operation could be separated into four (4) main duties, i.e. 1) one crew
for shooting the purse line, 2) one or two crew members for shooting the wing part of the net,
3) one crew for shooting the float line, and 4) one crew for shooting the marked buoy or light
raft if operation is done at nighttime.
46
The shooting position should be with the wind direction, at a distance of roughly 30 to
60 m from the fish school since the fish school usually swims against the wind direction. The
shooting speed should be the same as the full engine speed after which the speed can be
reduced when of net length has been released. When the fishing boat arrive the marked
buoy or light raft, the clutch is released and the marked buoy or light raft connected with the
wing net is retrieved onboard. Both ends of the purse line are then passed through the snatch
block at the foredeck main-mast. Purse line hauling could be done by using the capstan
winches on the starboard and port side. During the purse line hauling, few crew members
may swim near net gap at the foredeck in order to frighten the fish and prevent them from
escaping the net circle. After the purse line hauling, all purse rings are attached at the
foredeck and the purse line is pulled out of the purse rings then all crew could start hauling
the net at both sides of the vessel.
The bunt part of the net is hauled at the starboard side then the fishes are scooped.
Finally, the whole bunt part is lifted up onboard and all the remaining fish are transferred
from the bunt to the fish holds. Then, the purse seine net is rearranged for the next fishing
operation. The time spent for each operation depends on the number of crew, efficiency of
the crew, sea and weather conditions as well as the amount of fish. Nevertheless, the hauling
time usually takes 1-1:20 hours for a 600 m net with 16 crew members and the quantity of
fish is about 1.0 to 1.5 metric tons.
4.3.2 Luring light operation
The fishing operation is started while the quantity of fish in a school is adequate for
surrounding. The anchor of the light boat or light raft is hauled up and shooting operation is
started by surrounding the light boat. While the purse line is already hauled, the light boat
leaves from the net circle by pushing the float down the water and the light boat passes across
the float line. The light raft is restored at the stern deck. The remaining process is same as the
operation during the daytime.
Masthawee (1986) also described the operation of ordinary Thai purse seine (Uan
dum) with luring light lamps, where one to thirteen light rafts connected with an anchor was
deployed into the sea (Fig. 20). Some purse seiner fleet could consist of few luring light boats
operating in the fishing ground. The operation must wait until adequate fish schools gather
around the luring light boat or raft. If the weather and sea conditions are not favorable enough
for the fish to gather, the crew retrieves the light rafts onboard then the lights are turned off
with only the rafts remain in the sea. A small row-boat is deployed into the sea and the small
anchor at the remaining light raft is heaved up. Then the row-boat tows the raft away from the
net boat against the wind direction. After the surrounding operation, the row-boat with the
light raft must be maintained far away from the net gap at the foredeck of the net boat. The
lights of the mother boat must be turned off in order to prevent the fish school from escaping
from the net gap. After the purse line hauling, the light at the raft is turned off and both row-

47
boat and raft are removed from the net circle. Then net hauling operation is performed in the
same manner as that described in the 4.3.1.
Nowadays, 20-30 set of mercury lamps 500 w, 1000 w and 1500 w are installed
onboard a purse seiner and 10-20 lamps are installed at the light boat. During the luring light
operation, the net boat and light boat are tied together in the expected area of the target fishes.
The light boat and net boat are used at the start of the luring light operation which is usually
before twilight or in the early evening. When the fish school is observed to be in adequate
quantity and the environmental condition is suitable, the light boat is released from the net
boat and the lamps on the net boat are turned off one by one while the crew prepares for the
operation. The fishing operation starts by surrounding the light boat and hauling the purse
line after which the light boat crosses outside the circle net by pressing the float line beneath
the hull of the light boat. Some purse seiners deploy the light raft with row-boat instead of a
light boat. Hence, the lights in the raft must be turned on to aggregate the fish from the net
boat. Then the fishing operation continues as in the aforementioned.
4.3.3 Fish Aggregating Devices (FADs or Sung) operation
Thai fishermen prepare the anchored FAD using bamboo poles, wire and coconut
leaves, which together is fastened to a concrete block (Fig. 22). The purse seine operation by
surrounding FAD (coconut leaf shelter) as described by Masthawee (1986) is classified into
two (2) main operations, i.e. daytime fishing operation and nighttime fishing operation (Fig.
21 and Fig. 22).
4.3.3 (1)
Daytime fishing operation with FADs
This operation is conducted during the daytime usually after sunrise and before
sunset. Before the fishing operation, fish schools are located by hydro-acoustic equipment or
by ocular checking method. If there is inadequate fish school beneath the FADs, the first
FAD is pulled slowly by the net boat towards the second FAD. The fish school under the
shelter usually follows the first FAD. While approaching the second shelter, the net boat
accelerates its engine to full speed, pulling the first FAD passing the second FAD and
resetting in another location. The fish school from the first FAD usually moves to gather at
the second FAD. If the quantity of fish school is still inadequate, the fish school from the
second FAD is aggregated with the fish school under the third FAD by same method. The
operation starts by deploying a row-boat with a portable FAD. The row-boat slowly moves
against the current direction, while the FAD is slowly pulled by the net boat passing the rowboat with the portable FAD. While the net boat is pulling FAD and reaching the row-boat
with portable FAD, the net boat accelerates its engine to full speed, pulling the FAD while
passing the portable FAD and resetting in the other location. The fish school from the FAD is
gathered under the portable FAD. Then, purse seiner starts its shooting operation by
surrounding the row-boat and the portable FAD.

48
During the purse line hauling, the row-boat and portable FAD will be maintained at
the center of the net circle, far away from the net gap and foredeck of the purse seiner until
the purse ring is hauled up on the purse seiner. The portable shelter will be pulled up and
stored in the row-boat. The row-boat moves out of the net circle during the net hauling
operation. The remaining fishing operation is the same as in the aforementioned procedure.
4.3.3 (2)
Nighttime fishing operation with FADs
Conducted during the nighttime from sunset to sunrise, this technique is more
effective because the fishes are less frightened at night than at the daytime. In order to gather
big fish school, the FADs may be grouped by same method as in the daytime operation. A
light raft is attached at the FAD where sometimes more than one raft is set at different FADs
indicating that the operation for that night could be equal to the number of light rafts attached
with FADs. Before the fishing operation starts, the row-boat and portable FAD is deployed
into the sea and set against the current direction, 15-25 m far from the anchored FAD. The
light raft is moved from the FAD to the row-boat with portable FAD.
The purse seiner pulls the FAD with fish school passing the row-boat with light raft
and portable FAD. While the net boat is pulling the FAD and upon reaching the row-boat
with portable FAD, the net boat accelerates its engine to full speed while pulling the FAD,
passing the portable FAD and resetting in another location. The fish school from FAD is
gathered under the light raft and portable FAD. Then, the purse seiner starts the net shooting
operation by surrounding the row-boat and portable FAD. The fishing operation is the same
as already described in the aforementioned procedure. After the hauling and the catches are
transferred to fish hold, the operations are continued to the other light rafts with FADs as
done before.
Most purse seine operations in Thailand make use of the combination of two of the
three luring methods, i.e. using fish shelters and fish luring lights. The fishermen aggregate
the fish school by tying the light raft with the anchored FAD. While the fish school is
observed to be of adequate quantity for the fishing operation, a small boat takes the light raft
away from the anchored FAD. Fishing operation is conducted by surrounding the small boat
and the light raft.
For Uan dam and Uan lom sung, fishing operation is conducted from a single boat.
The net is hauled by hand on both sides of the boat, while the purse line is pulled by a capstan
winch which is driven by the boats main engine. Nowadays, a net hauler is installed at the
port side to save on manpower.
4.4
Two-boat purse seine or Uan Tang-ke
Fishing operation of Uan Tang-ke is conducted by using two row-boats each boat
carries half the piece of the purse seine net. The fishing operation starts by searching the

49
fish school both visually and using hydro-acoustic method. Searching is carried out on the
mother boat and when the fish school is located, the 2 row-boats are released into the sea
(Fig. 25). Both row-boats will row and shoot the net around the fish school. Then the purse
line is hauled up on the 2 row-boats manually or by the capstan winches until the bottom
part is closed. The wing parts are hauled up manually on the row-boat until reaching the
bunt part. Then the mother boat is maneuvered to attach the float line of bunt for
transferring the catch to the fish holds. Finally, the purse seine net will be arranged for the
next fishing operation. The number of crew on both boats could be 18-30 persons,
depending on the size of the 2 row-boats and the net. Considering that the fishery resources
had already been depleted, the Chinese purse seine applying the luring light technique is
also used to aggregate the fish school. The light raft and light boat are used only to control
the light during the nighttime operation.

50
5.
Thai Purse Seiner
Masthawee (1986) described the Thai purse seiners as made of wood, size between 10
to 120 gross tonnage and length overall (LOA) is between 12 to 24 m. The purse seiner is
usually installed with motor engine, some of which could be used marine engine while some
could be modified truck engine between 22 to 500 HP (Fig. 16). An electric generator and
electric pump are generally installed in the engine control room.
The wheelhouse is located at the stern occupying slightly less than half of vessels
width. The top of wheelhouse is installed with main crews nest where the fishing master
stays while searching for the fish school. The fish finder, sonar and echo-sounder including a
radar and radio transceiver are installed in the crews nest (Fig. 32). The foredeck main mast
is installed near the bow, the height of which is between 1.3 to 5.0 m depending on the length
of the purse seiner. There are 2 snatch blocks installed at both sides of the vessels foredeck
for passing the purse line to the capstan winches at the front of wheelhouse, and the other 2
blocks hung on the main foredeck main mast, for facilitate hanging of the purse rings after
completing the purse line hauling operation. In front of wheelhouse, 2-4 capstan winches are
installed, to be used in hauling the purse line, anchor line and scoop line as well as for
transferring the catch from the bunt into the fish holds. Catches are stored in 3-10 fish holds,
installed under the working deck.
A bamboo or Polyethylene or stainless pole, diameter 4-5 inches, is fixed from
foredeck main mast to the wheelhouse to be used in rearranging the net after each fishing
operation. There are 2 utility booms fixed at the starboard and port side. Starboard boom is
used for pick up the float line of the bunt part above the sea surface to prevent the fishes from
escaping from the bunt. A utility gondola is also stored at the stern deck which is heaved up
onboard using the winch at the foredeck.
Fig. 32. Thai anchovy purse seiner

Photo by A. Munprasit (2009)

51
6.
Design of Fish Aggregating Devices (FADs) for Purse Seining in

Thailand
Fish Aggregating Devices (FADs) have been used by Thai fishers to aggregate fish
schools for a long time. As of 1969, there are few designs of FADs based on the target
species and fishing gear, the most common of which are the bush pile for encircling net and
fish shelter for purse seine and lift net.
6.1
Bush pile for encircling net
Called Grum in Thai language, the bush net is used in sea depths of less than 8 m
based on the target species. It is made of wooden poles or tree branches stuck into the sea
bottom. The fishing gear operating with bush pile encircles the net or the bamboo screen
block trap.
6.2
Fish shelter for purse seine and lift net
Also known as Sung in Thai language and Uyuam in Malay language, this FAD is
very famous for purse seining operation in Thailand. In the marine fisheries statistics of
Thailand, marine production by purse seine with FAD had been recorded in 1974 as almost
equal to the data from purse seine by free fish schooling (See Appendix 2). FADs in Thailand
come in various designs for small-scale and large-scale fisheries purposes. FADs for purse
seine fishing operations are being used in the Gulf of Thailand as well as in the Andaman Sea
(Fig. 33).
Fig. 33. Local FAD in a fishing ground of the Andaman Sea

http://www.chinglewtackle.com/index.php

52
Masthawee (1986) and the result of a fishing survey by SEAFDEC fishing gear
technologists in 2003 described the materials and construction of the Thai FADs for purse
seining in the central part of the Gulf of Thailand, which are usually set in depths ranging
from 20 to 50 m. The FAD is composed of bamboo pole, anchor line, weight and coconut
leaves, the details of which are described below:
1) One to three bamboo poles, 10-15 m in length are tied together by iron wire. A
hole is drilled at the base of the bamboo pole for passing the iron wire or a piece of
40 mm diameter polypropylene rope. The iron wire or rope is spiked into a big ring
to serve as joint with the anchor line.
2) Coconut leaves are individually tied with the anchor line. The number of coconut
leaves would depend on the sea depth, but usually 7 to 20 fronds are set with a
FAD at intervals of 1-3 m.
3) Iron wire No.12 or No.13, diameter 3-4 mm, 3-5 pieces are twisted together or
polyethylene rope diameter 10-12 mm, or iron wire 5-6 mm diameter, is used as
anchor line. The length of the anchor rope is shorter than sea depth by about 3-5 m.
4) Stone or sand bag weighing 40-50 kg serves as sinker in shallow water area. In the
deeper areas, the sinker used for fixing FAD should weigh 70-130 kg. Nowadays,
some concrete weight is used replacing the stone because big stones suitable for a
sinker of the FAD are rarely found.
Construction of a FAD is carried out onboard during the trip to the fishing ground and
setting is done one by one in the fishing ground. The interval of each coconut leaf-FADs
should be 500-1000 m distance. Generally, purse seiners deploy 20-50 sets of FADs for their
fishing operations. The fish schools usually concentrate around the FADs after 1-2 weeks
from setting, although in some areas where fish is abundant, aggregation in the FADs could
be observed after 3-5 days. The life expectancy for this model of FAD is 2-3 months.
Other FADs design was found in the eastern part of the Gulf of Thailand in Rayong
Province. The details of the FAD constructed by small-scale fisherman for squid jigging, set
at the depths of around 20-25 m are described below and shown in Fig. 34.
1) One bamboo pole, 5-7 m in length is tied together with a piece of Styrofoam with
buoyancy of about around 2 kg. Coconut leaves are individually tied with the
anchor line. The number of coconut leaves is depends on the sea depth but usually
5 to 7 fronds are set with a FAD at intervals of 1-2 m.
2) Polyethylene or Polypropylene rope diameter 5-7 mm is used as anchor line. The
length of the anchor rope is shorter than sea depth about 1-2 m. A stone or sand
bag weight or concrete weight, 15-20 kg serves as sinker.

53
FADs in Rayong Province are usually deployed in groups. Each group of FADs is
composed of 5-7 individual FADs. The design of the FADs in the Andaman Sea, specifically
in Phan-gna Province, is almost same as the FADs design in the Gulf of Thailand. On the
other hand, for purse seine fishing at the deeper depths in the Gulf of Thailand at around 5060 m, the design of the FADs is detailed below:
1) One bamboo poles, 6-8 m in length are tied together with a piece of Styrofoam
with buoyancy of around 2 kg. Coconut leaves are individually tied with the
anchor line. The number of coconut leaves depends on the sea depth.
2) Polyethylene or Polypropylene rope diameter 10 mm or iron wire 4-5 mm diameter
is used as anchor line. The length of the anchor rope is shorter than sea depth by
about 3-5 m. A few pieces of concrete weight made of 200-liter drum filled with
concrete, is used as sinker.
Fig. 34. Construction of FAD (Sung) for Thai purse seining in the central part of the Gulf of Thailand
Masthawee, 1986

54
7.
Pelagic Resources for Thai Purse Seine Fisheries
There are six (6) important pelagic resources that are targeted for purse seine fisheries
in Thailand, which had been summarized by Bhateyasevi (1997) and Ratanawalee (2009).
7.1
Indo-Pacific mackerel (Rastrelliger brachysoma/neglectus)
Found in the Thai waters of the

Gulf of Thailand and the Andaman Sea,
the Indo-Pacific mackerel (Fig. 35)
inhabits the coastal area in the Gulf of
Thailand at depth of 50 m or less. When
its length reaches 10 cm, it migrates to a
spawning area particularly in the western
part of Gulf of Thailand to northern part,
where it seeks for food and grows where
there
is
high
productivity
of
phytoplankton.
Fig. 35. Rastrelliger brachysoma

http://www.fishbase.org, (2009)
Several tagging studies on the Indo-pacific mackerel revealed that there are two
stocks of Indo-Pacific mackerel in the Gulf of Thailand. One is a straddling stock between the
eastern part of the Gulf of Thailand and Cambodian waters, while the other is a migratory
stock between the inner and the upper Gulf of Thailand (Bhatiyasevi referred to Somjaiwong
and Chullasorn, 1974).
Indo-Pacific mackerel is also found in the Andaman Sea at depths ranging from 10 to
40 m, most substantially in Phang-Nga Bay to Satun Province in the border area between the
Thai EEZ and Malaysian EEZ. The fishing ground is also found in Ranong Province in the
border area between Thai the EEZ and Myanmar EEZ. A migratory tagging study found that
the Indo-Pacific mackerel in the Andaman Sea can be categorized into three (3) groups. The
first group is distributed around Ranong Province in the border area between the Thai EEZ
and Myanmar EEZ, which means that this group is a shared stock between Thailand and
Myanmar. The second group is distributed around Phuket Island and Krabi Province. The
third group is distributed in Satun Province in the border area between the Thai EEZ and
Malaysian EEZ, suggesting that this group is a shared stock between Thailand and Malaysia
(Somchaiwong et al., 1984).
The annual catch of the Indo-Pacific mackerel in the Gulf of Thailand from 1971 to
1994 ranged from 26,129 to 99,638 metric tons with the minimum in 1977 and maximum in
1984. The assessment on the state of stock indicated that the maximum sustainable yield
(MSY) is about 104,000 metric tons at an exerted fishing effort of about 146,600 days of a
Thai purse seine (Rattanawalee referred to Tantisawetrat, 1994). This indicates that the IndoPacific mackerel in the Gulf of Thailand has been fully exploited since 1984.

55
7.2
Indian mackerel (Rastrelliger kanagurta)
The Indian mackerel (Fig. 36) is

generally distributed in the Gulf of
Thailand both in shallow and deep
waters, with the peak of the catch in
depths ranging from 30 to 50 m. The
spawning grounds are in two areasbased
on the spawning season. From July to
August, the spawning ground is around
Prachaub Kirikharn Bay, and during
January to March, the spawning ground
is around Surat Thaini Bay.
Fig. 36. Rastrelliger kanagurta

The Indian mackerel in the Andaman Sea is distributed along the coasts from Ranong
Province to Phan-Nga Province, Phuket and adjacent areas off Trang Province and limited
area in the northern of Taru-tao Island. The fisheries for Indian mackerel had been
remarkably observed since 1973 due to the development and expansion of the luring purse
seine fisheries to the offshore areas. Since then, production increased from 12,690 metric tons
in 1973 and peaked to 50,574 metric tons in 1983. After this period, the catch had been
reported to have somewhat fluctuated showing slightly decreasing tendencies.
Rattanawalee (2009) referred to Tantisawetrat (1996) estimated that the maximum
sustainable yield for the Indian mackerel in 1984-1993 in the west coast of the Gulf of
Thailand (areas II, III and VI) applying the virtual population analysis and surplus production
model was 32,866 metric tons and 32,533 metric tons, respectively. The analysis indicated
that an optimum fishing effort should be 112,500 days fishing using luring purse seine. This
indicated that no definite sign of overfishing has been observed yet. In this regard, it has been
suggested that the mesh size of the luring purse seine should be enlarged to 3 cm instead of
2.5 cm used at the present because records have shown that small size fish had been caught in
substantial quantities, then more yield of about 20% could be obtained.
7.3
Sardines (Sardinella spp.)
Six (6) species of sardines have been found to be dominantly distributed in the Gulf of
Thailand (Fig. 37 and Fig. 38). However, three (3) most common species, i.e. Sardinella
gibbosa, S. frimbriata and S. albella share 95% of the countrys total catch of sardines. Small
sardines inhabit the waters from the shoreline to 20 m depth, while big size are found in the
deeper waters from 20 to 50 m. The fishing grounds for sardines in the Gulf of Thailand are
separated into various areas. The fishing ground in the Upper Gulf of Thailand is in
Samutprakarn and Petchaburi waters.

56
For the Western Gulf of Thailand, the fishing grounds are in Prachaub Kiri Kharn,
Chumphon and Surat-Thani waters, while for the Southern Gulf of Thailand, the fishing
ground is from Nakhon-Sri-Thammarat to Pattani waters. The fishing ground of sardines in
the Central of Gulf of Thailand is off
Chumphon where the depth greater than 45 m.
The Fishing ground of sardines in the Andaman
Sea is distributed along coastline of Ranong
Province where the fishing ground is scattered,
while the fishing ground in the southern part of
Phuket in Phan-Nga Bay is spread area to
Krabi, Trang and Satun Provinces.
Sardines are exploited in substantial
amount after 1973 similar to the Indian
mackerel. Its production had increased year
after year and hit the peak of 203,364 metric
tons in 1977. The production showed a
decreasing trend to 68,447 metric tons in 1985
and henceforth, it increased again to about
110,000-140,000 metric tons per annum.
From 1983, the number of purse seines
showed an increasing trend but the production
of sardines did not subsequently increase. It is
estimated that the maximum sustainable yield of
the sardine stock in the Gulf of Thailand should
be around 104,000 metric tons with an optimum
fishing effort of about 190,000 days of luring
purse seine. It is obvious that fishing effort
expended to sardine fisheries was beyond the
optimum level since 1988. Therefore, sign of
overfishing is obvious and it is recommended
that the fishing effort should be reduced by
about 14% in order to save the depleted sardines
stock.
7.4
Fig. 37. Sardinella gibbosa

Fig. 38. Sardinella frimbriata (top) and

Sardinella albella (bottom)
Round scads (Decapterus spp.)
The species of round scads (Fig. 39) that share 96.6% of the total production of scads
is the long-finned round scad (Decapterus maruadsi), while the short-finned round scad
(Decapterus macrosoma) share 3.4%. The distribution of the round scads is generally in
water depths of 20 to 70 m. The fishing ground in the Gulf of Thailand is around the central
part of the Gulf of Thailand, particularly off the coast of Rayong and Trat Provinces. The
57
fishing season is between October to February, while the spawning season in the Gulf of
Thailand is throughout the year but peaks in February to March and July to August.
Three species of round scads are found in the Andaman Sea, i.e. long-finned round
scad (Decapterus maruadsi), short-finned round scad (Decapterus macrosoma), and the other
one is the big round scad (D. macarellus). All species of round scads are found scattered
along the coast of the Andaman Sea from Ranong to Satun Provinces. Spawning season of
round scads in the Andaman Sea is during northeast monsoon season (December to May).
It is well known that the remarkable development of purse seine fisheries in Thailand
arose from the discovery of new fishing
grounds in the middle of the Gulf of
Thailand since year 1973, particularly for
the round scads which are mainly caught by
luring purse seine using the bunches of
coconut fronds or FAD as lure operated at
daytime in the water depth of 30-50 m.
This resulted in the abrupt increase
in the catch from 660 metric tons in 1972 to
be 12,690 metric tons in the next year and
increasing steadily to its maximum catch of
129,800 metric tons in 1977, and after
which it decreased year after year to only
about 20,000 to 40,000 metric tons/year
during the past 15 years. There is no doubt
that the round scads that had been heavily
exploited in such short period of time, and
had already been depleted since 1977 up to
the present.
7.5
Fig. 39.Decapterus maruadsi (top) and Decapteru macarellus (bottom)

Anchovies (Stolephorus spp.)
There are 10 species of

anchovies (Fig. 40) found in the Gulf
of Thailand and the Andaman Sea,
and
Encrasicholina
heteroloba
(Steleophorus heterolobus) is the most
common accounting for 86.6% of the
total anchovy production from the
Gulf of Thailand and 78.9% from the
Andaman Sea. The distribution along
the eastern of the Gulf of Thailand is
Fig. 40. Encrasicholina heteroloba


58
from the coast of Cambodia to the coastal areas of Chonburi Province. Anchovies have also
been found to be abundant around Chang and Kood Islands.
The distribution along the coast of the western part of Gulf of Thailand is from
Prachaub Kirikharn, Chumpon, Surat Thani, around Tao, Pha-Nhga and Samui Islands. The
fishing ground is also found along the southern part of the Gulf of Thailand from NakhornSri-Thummarat to the Malaysian waters. Anchovy fishery is heavily found in Phuket and
Satun Provinces.
The catch of anchovies have been remarkably increased after 1981 due to the
development of fishing techniques using light to attract fish schools at night time and the
efforts of fisheries to move further offshore. This resulted in the increase of catch from the
level of 10,000-20,000 tons to 103,101 metric tons in 1985 and the catch has been maintained
at the level of 110,000-120,000 metric tons during the past 5 years. It has been estimated that
the maximum sustainable yield of anchovies in the Gulf could be around 104,000 metric tons.
This means that the anchovy resources had been heavily exploited since 1985, thus attempts
to increase the fishing effort should be carefully considered.
7.6
Neritic tunas (Thunnus tonggol, Euthynnus affinis and Auxis thazard)
The small or neritic tunas (Fig. 41) found in the Gulf of Thailand are of three (3)
dominant species, i.e. longtail tuna (Thunnus tonggol), kawa kawa (Euthynnus affinis) and
frigate tuna (Auxis thazard). Fishing grounds in the Gulf of Thailand are spread out in the
coastal areas from the eastern part of the Gulf of Thailand, Trad Province along the coast to
the western part of Gulf of Thailand, Surat Thani Province and around Ko Pha-Nhga and Ko
Samui Island. Other offshore fishing grounds are in the deep waters in central part of the Gulf
of Thailand, i.e. off Chumphon Province coast to Nakhon Sri Thammarat Province. Fishing
season in the Gulf of Thailand is affected by the monsoon season, thus the fishing season in
western Gulf of Thailand is from October to April (northeast monsoon season) and in Eastern
Gulf of Thailand is from April to September (southwest monsoon season). The fishing season
along the Thai-Malaysian waters is during the northeast monsoon from March to December
(Bhatiyasevi, 1998 referred to Supongpan and Saikliang, 1987). Fishing ground in the
Andaman Sea is scattered along the coastal areas. Kawa kawa and frigate tuna are distributed
in Surin and Similan Islands, Trang Province but rarely in Satun Province. Longtial tuna is
less dense compared with the other small tunas.
The neritic tuna resources in the Gulf of Thailand prior to the 1980s were relatively
low with production of 3,298-19,929 metric tons, but the fishery was rapidly developed after
1982 due to strong demand from the countrys tuna canning industries. Since 1982, neritic
tuna fisheries had also been dramatically expanded due to the improvement in fishing gear
and fishing methods using the purse seine. Furthermore, new fishing boats of bigger sizes had
been installed with built in freezers to preserve the catch in the high seas where a longer
period of time is needed for one trip. Thus, the catch has increased from 39,368 metric tons in
1982 to 157,163 metric tons in 1992, which was also partly due to the promotion of tuna
59
fisheries outside the Thai waters through joint ventures or fishing agreements with
neighboring countries, and also the exploration for new fishing grounds. The maximum
sustainable yield for neritic tunas which had been estimated by observing the yield curve
established from the relationship between the total catch and fishing effort, was 86,000 metric
tons (Rattanawalee, 2009 referred to Chuenpun, 1996).
Fig. 41. Thunnus tonggol (top left), Euthynnus

affinis (top right), and Auxis thazard (bottom left)
http://www.fishbase.org (2009)
In order to mitigate the aforementioned depletion of the countrys pelagic resources, the
DOF/Thailand had issued various diversified fisheries regulations for implementation in the
Thai Waters. Rattanawalee (2009) summarized the current management regimes with regards
to purse seine fisheries, as shown in Table 5.
Table 5. The marine fisheries management measures in Thailand.
Period of prohibition
Whole year
Management measures
Types of gear
Distance of 3,000 m in some areas of Trawls, Push net, Purse seine,
Prachuab Khiri Khan and Chumphon Shortnecked clam dredge, the
Provinces affected by Typhoon Gay
fishing gear with light luring
Whole year
Some areas in Trat Province (within 15 km Purse seine with light luring
from shore)
All areas in the Gulf of Thailand and the Purse seine mesh less than 2.5
Andaman Sea
cm (used in night time
operation)
Sea turtles and turtles eggs
All gears
Sea Dugong
Sea Corals
Dolphins
No fishing in the preservation area
Certain areas in Phuket Province
Certain areas in Chumphon Province
Certain areas in Trat Province
Certain areas in Phang-nga Province
Whole year
Whole year

60
Table 5. (Cont.) The marine fisheries management measures in Thailand.

Period of prohibition
Whole year
3 months
(15 Feb-15 May)
3 months
(Oct-Dec)
3 months
(1 Dec-28 Feb)
2 months
(15 Apr-15 Jun)
Management measures
Distance of 3,000 m from shoreline in
certain areas in Prachuab Khiri Khan to
Chumphon Province used for the pilot
CBFM project
Protection of fish spawners and larvae in
certain areas in Prachuab Khiri Khan,
Chumhon and Surat Thani Provinces
Types of gear
Trawl, Push net, Purse seine,
Clam dredge and Light luring
nets
Pair trawl, Otter board trawl,

Purse seine, Mackerel
encircling gill net, except otterboom and beam trawl fishing
at night time during 15 Feb-31
Mar and fishing at both night
and day time during 1 Apr-15
May
No fishing of female eggs-berried mud crab, All gears
swimming crab and Charybdis feriatus
Protection of Horse Shoe crab in Phang-nga All gears
Bay including in the rivers around Phangnga Bay
Protection of fish spawners and larvae in All trawlers, Purse seine, Gill
Phang-nga Bay, from Krabi to Phuket net with mesh size not less
Provinces
than 4.7 cm
Source: Fish Stocks and Habitats of Regional, Global and Trans-boundary Significance in the South China Sea:
Case Study on the Gulf of Thailand

61
8.
Appendices
Appendix 1: Thai fisheries in General

Rattanawalee (2009) summarized Thailands marine fisheries, which are as complex
as the fisheries in other tropical countries. The large number and different sizes of fishing
boats employing multi-gear in multi-species fisheries traditionally feature the type of
fisheries in Thailand, classified nonetheless in two categories, i.e. small-scale and
commercial fisheries. The small-scale fisheries employ small fishing boats (not larger than
5.0 gross tons displacement), equipped with simple fishing gear, either without engine or with
engines that are not bigger than a 30 HP. Fishing operation is largely conducted in inshore
fishing grounds (not more than 5 km from the shore). The small-scale fisheries are subsistent,
and operated mainly by family members in 2,500 coastal villages throughout the country. On
the other hand, commercial fisheries employ fishing vessels of larger sizes, with efficient
gears and are capital intensive. Generally, the marine fisheries of Thailand can be described
as follows:
Fishing households
Referring to the marine fisheries inter-census survey in 2000, some 57,801 families
are engaged in either full-time fishing or part-time supplemented with aquaculture. The
number of fishing households increased by 8.8% from that enumerated during the 1995
marine fisheries census.
Fishers
The survey report in 2000 revealed that from the total number of 158,166 fishermen,
the great majority (82.2%) are male. Some 56.3% of the fishermen are from 30 to 50 years of
age, followed by 24.3% younger fishermen, and the rest 19.4% belonged to the group of
older fishermen. Despite the substantial increase of 15.1% in the number compared to that in
the 1995 census, a noticeable drop in the number of young fishermen group from 32.5% to
24.3% connotes a waning interest in fishing career among the young generations. Greater job
opportunities in other economic sectors coupled with the risky and laborious nature of
working at sea may have pushed the younger Thais to turn away from fishing.
Fishing gear
Fishing gears can be classified into two major groups, i.e. small-scale and commercial
fishing gears. In 2000, it was found that more than one-half (54.8%) of the small-scale fishing
families employed gillnets (largely shrimp trammel net and crab gill net), followed by 15.2%
who used traps (fishing for cephalopods, blue swimming crabs, and mud crabs). Between
1995 and 2000, trawling became less popular both in small-scale and commercial fisheries;
however, more small-scale (but not commercial) fishermen turned to anchovy falling net with
luring light.
Fishing vessels
As reported in the marine fisheries inter-census survey in 2000, the total fishing fleet
of 58,119 vessels comprised 72.7% with outboard engines, the majority of which are long-tail
boats. The remaining 22.8% were fishing vessels with inboard engines, and 4.5% with no
engines.

62
Fishing grounds
Thailands EEZ spans over an area of 420,280 km2: 304,000 km2 in the Gulf of
Thailand and 116,280 km2 in the Andaman Sea. Five major fishing grounds can be identified
in the Gulf of Thailand, i.e. the Eastern, Inner Gulf, Upper Western, Lower Western, and the
Mid-Gulf. The fishing grounds in the Andaman Sea are largely around the various islands
and continental shelves (Fig. 42).
Fig 42. Thailand EEZ

Sopana Boonyapiwat, et.al. (2008)

63
Appendix 2. Statistics on marine catch by purse seines (1955-2006)

Year
Catch by Purse seine

Thai Purse
seine
Anchovy purse
seine
Chinese Purse
seine
Tuna Purse
Seine
Annual catch
Total
1957
170,900
1958
145,000
1959
147,770
1960
146,470
1961
233,275
1962
269,709
1963
323,374
1964
494,196
1965
529,483
1966
635,165
1967
762,187
1968
1,004,058
1969
1,179,595
1970
1,335,690
1971
1,470,289
1972
1,548,157
1973
1,548,157
1974
128,185
11,676
11,151
151,012
1,351,590
1975
153,053
7,506
13,572
174,131
1,394,608
1976
282,546
5,870
4,956
293,372
1,551,792
1977
427,540
2,100
7,504
437,144
2,067,533
1978
353,931
4,046
3,721
361,698
1,957,785
1979
279,207
9,174
4,460
292,841
1,813,185
1980
235,276
5,755
3,591
244,622
1,674,953
1981
315,752
6,441
4,586
326,779
1,488,978
1982
302,556
16,298
13,986
332,840
1,577,334
1983
400,267
40,000
29,208
469,475
1,651,882
1984
406,058
87,824
23,052
516,934
1,653,266
1985
471,211
88,651
11,055
570,917
2,057,751
1986
550,780
48,969
2,606
602,355
2,348,572
1987
610,056
29,945
640,001
2,601,929
1988
571,728
60,740
632,468
2,337,215

64
Appendix 2 (Cont.)
Year
Catch by Purse seine
Annual catch
Thai Purse
seine
Anchovy purse
seine
Chinese Purse
seine
Tuna
Purse Seine
1989
568,440
105,613
674,053
2,539,237
1990
611,831
145,681
757,512
2,555,417
1991
617,303
120,508
737,811
2,709,051
1992
675,252
161,554
836,806
2,965,723
1993
701,540
152,850
854,390
2,754,486
1994
769,509
155,405
924,914
3,150,233
1995
771,698
147,034
918,732
2,827,400
1996
709,167
146,539
855,706
2,786,125
1997
658,773
143,850
802,623
2,679,500
1998
642,986
143,438
786,424
2,708,968
1999
626,353
126,808
753,161
2,725,207
2000
577,976
134,951
712,927
2,773,665
2001
541,303
135,537
678,840
2,631,700
2002
554,558
141,385
695,943
2,643,711
2003
558,659
152,248
710,907
2,651,223
2004
599,480
157,151
756,631
2,635,969
2005
609,796
159,735
11,937
781,468
2,615,565
2006
536,145
151,720
22,622
710,487
2,484,893
Total

65
Appendix 3: Number of purse seiners (1955-2006)

Number of Purse Seiners
Year
Thai
Anchovy
Chinese
Purse seiner
purse seiner
Purse seine
Total
1955
175
139
314
1956
196
185
381
1957
116
117
233
1958
188
179
367
1959
198
196
394
1960
171
193
364
1961
141
165
306
1962
112
92
204
1963
112
126
238
1964
91
127
218
1965
58
160
218
1966
84
159
243
1967
224
100
324
1968
347
53
400
1969
363
35
398
1970
475
35
510
1971
477
31
508
1972
344
64
408
1973
515
103
54
672
1974
554
82
39
675
1975
567
40
18
625
1976
651
58
17
726
1977
665
19
22
706
1978
707
31
15
753
1979
615
51
15
681
1980
735
12
34
781
1981
787
32
14
833
1982
771
56
13
840
1983
731
97
16
844
1984
790
55
16
861
1985
819
197
17
1,033
1986
836
143
17
996
1987
1,043
117
14
1,174

66
Appendix 3 (Cont.)
1988
1,241
199
16
1,456
1989
1,079
348
16
1,443
1990
1,262
367
12
1,641
1991
1,243
347
24
1,614
1992
1,128
324
1,452
1993
1,173
336
1,509
1994
1,163
348
1,511
1995
1,022
375
1,397
1996
905
422
1,327
1997
999
503
1,502
1998
966
323
1,289
1999
1138
416
1554
2000
990
514
1,504
2001
1,071
378
1,449
2002
1,260
426
1,686
2003
1,313
324
1,637
2004
1,135
344
1,479
2005
1,186
359
1,545
2006
1,164
326
1,490

67
9.
Acknowledgment
The authors would like to express deep appreciation to Prof. Dr. Takafumi Arimoto,
Professor from the Fish Behavior Section, Tokyo University of Marine Science and
Technology of Japan for his support in the participation of the authors during the purse seine
fishing trials for the new specification of purse seine fishing gear, carried out by instructors of
the Tokyo University of Marine Science and Technology from 6 to 16 July 2009. The authors
would also like to express their special gratitude to Mr. Aussanaee Munprasit, Assistant
SEAFDEC Department Chief, SEAFDEC/TD for his recommendations and suggestions for
this purse seine research activities and for providing information related to Thai purse seine
fisheries, and to Ms. Rattanawalee Phoonsawadi for kindly allowing the authors to include
the status of pelagic resources in this report based on what she had already concluded and
presented during the Seminar on the Assessment of Fishery Stock Statistics in the South and
Southeast Asia. The authors are also thankful to the former SEAFDEC Secretary-General and
Training Department Chief, Dr. Siri Ekmaharaj, to Dr. Yuttana Theparoonratana and Dr.
Worawit Wanchana, and to all SEAFDEC/TD Division Heads for kindly supporting the
authors during their participation in the research works in Japan. Finally, the authors would
like to offer special thanks to the JSPS-NRCT for their funding support that made this
research possible.

68
10.
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Purse Seine Fisheries of Thailand

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Purse Seine Fisheries of Thailand

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Purse Seine Fisheries of Thailand

Weerasak Yingyuad1 and Isara Chanrachkij2

Purse Seine Fisheries in Thailand

Weerasak Yingyuad1 and Isara Chanrachkij2

: Coastal and Small Scale Fisheries Management Division

: Capture Fisheries Technology Division (Correspondence person)

Introduction: Purse Seine in General

Background of Thai Purse Seine Fisheries

History of Thai Purse Seine Fisheries

Statistics on Thai Purse Seine Fisheries

Categories of Purse Seines in Thailand

Categories of Surrounding Nets Classified by the Department of

Categories of Surrounding Nets Classified by SEAFDEC/TD

Categories of Surrounding Nets Classified by FAO (ISSCFG)

Principles of Thai Purse Seine Fishing Operations

Thai Purse Seiner

Design of Fish Aggregating Devices (FADs) for Purse Seining in Thailand

Pelagic Resources for Thai Purse Seine Fisheries

Appendix 1: Thai Fisheries in General

Appendix 2: Statistics on marine catch by purse seines (1955-2006)

Appendix 3: Number of Purse Seiners in Thailand (1955-2006)