Technical background
China marine site is vast, the mariculture development is swift and violent, and cultured output occupies first of the world, and wherein shellfish culture accounts for more than 75% of gross yield, the shellfish culture of long-term large scale and high density has partly been cultured the marine site in Liaoning etc. and has been caused that seawater nutrient descends, current are smooth, damage by disease and insect takes place frequently.Low and the large-area sudden death of quality shellfish improves the marine shellfish aquaculture cost, and risk increases.Changhai County, Liaoning Province, shellfish culture base with China's maximum is an example, and 1-6 month seawater aquaculture output had fallen 33.8% on a year-on-year basis in 2007.
How to evade the shellfish culture risk, the adjustment breed variety of suiting measures to local conditions, it is scientific and reasonable that to utilize marine resources to become inferior position be one of new problem of facing of mariculture industry into advantage.
Description of drawings
Fig. 1 is when cotidal and co-ranged position not, the residing location state diagram schematic diagram of cylinder mould, and (1) is that buoyant spheres, (2) they are that buoyancy rope, (3) they are that raft body, (4) they are that lifting rope (5) is that cylinder mould (6) is that sandbag (7) is rod (bamboo pole).A, B, C represent respectively full sea, half tide, low tide, the time sea the position, D represents the position in seabed.
Fig. 1-1 represents the time of low water, the state in the heavy fully seabed of cylinder mould.
When Fig. 1-2 represents half tide, the state in cylinder mould half heavy seabed.
During Fig. 1-3 expression full sea, cylinder mould breaks away from the state in seabed fully.
Fig. 2 is the left view of Fig. 1-3.
Fig. 3 is improved cylinder mould dividing plate, is to process two big holes on original cylinder mould dividing plate.
Embodiment
Adjust raft body and the buoyancy rope and the lifting rope length of buoyant raft by above-mentioned Fig. 1, make it can be in the time of low water, the buoyancy rope adds the length of lifting rope greater than the distance of sea to the seabed, guarantees that cylinder mould can sink to the seabed fully, and at the incoming tide, cylinder mould can break away from seabed (as Fig. 1-3) fully.
The concrete length of buoyancy rope and lifting rope is relevant with the quality in seabed, and buoyancy rope and lifting rope are short at the bottom of the silt, prevent that cylinder mould from being sticked by silt.Otherwise husky mud spacer screen cage is difficult for being fallen into, and can suitably add the length of buoyancy rope and lifting rope, makes cylinder mould long in the seabed time of staying.
Cylinder mould is stretching, again two rods (bamboo pole) are fixed together with cotton rope and cylinder mould, make cylinder mould keep propping up attitude.
The cylinder mould dividing plate of original shellfish culture is formed 1.5~2 times of diameter by sea cucumber make a call to two circular holes.Also can be in addition
Row is ordered the cylinder mould that satisfies above-mentioned condition.Two circular holes be for make sea cucumber can be in cylinder mould easy on and off current, ingesting etc. to sea cucumber provides more convenience.
The cylinder mould bottom is hung sandbag (6) prevent that impacting lower net cage in trend too drifts about.
According to the distance between the individual size adjustment cylinder mould dividing plate of culturing sea cucumber, select the suitable net sheet of mesh.
Determine cultivation density according to the sea area natural environment.To the seabed have enrich food resource cultivation density more greatly, otherwise then littler.General sea area through long-term shellfish culture, the seabed food resource is all abundanter, and each raft is hung 60-80 cylinder mould.
Selecting not bait throwing in is children's ginseng about the long 3cm of body that breeds in the middle of condition marine, and every cage 40-60 head (15 layers of dividing plate) does not have the bait throwing in breed.Adjust the buoyancy rope in good time in breeding process, can promote that sea cucumber grows fast, culturing the sea area with the smooth shellfish of shrimp is example, and the general depth of water is all more than 10 meters, and there is a fixed difference difference in Various Seasonal sea and seabed.The summer high-temperature phase allows cylinder mould stop in the seabed as far as possible, and marine organisms are active at the beginning of spring and summer, water temperature is suitable can improve cylinder mould, and that has a mind to allows various marine organisms such as mussel attached on the cylinder mould, replenishes how natural organic nutrient substance to sea cucumber.
Seedling can hang on the buoyant raft at the opening cylinder mould sky that prop up rod summer under autumn end if select, allow and overwork attachment inside and outside the cylinder mould, to the certain natural organic bait of sea cucumber deposit, but during toward the interior dress of cylinder mould seedling, harmful animal things such as the fish in the cylinder mould, crab, starfish to be removed, behind the sea cucumber seedling of packing into cylinder mould be sewed up with cotton rope.
This cylinder mould is cultured the invasion that the sea cucumber method can also effectively prevent sea cucumber harmful animals such as fish, crab and starfish.
Sea cucumber is an omnivore, marine site in condition can be on the lifting rope at cylinder mould top, hang and support some green plantss such as sea-tangle, undaria pinnitafida etc., specifically can be with reference to the cultural method of sea-tangle and undaria pinnitafida, select will grow into suitable opportunity sea-tangle more than 1 meter or undaria pinnitafida and connect rope (band root) and be transplanted on one's body the raft at cylinder mould top.And allow the blade in growing can contact as much as possible near to cylinder mould, make cylinder mould sea cucumber under suspended state that the chance of feed also be arranged.
Holothruian cultures through one-period 2-3 improve the marine eco-environment, and the nutriment that shellfish needs is restored, and a part of platform raft is changed support shellfish again, are implemented in the certain sea area, and sea cucumber and shellfish are with supporting.Like this can be under the prerequisite of marine ecology balance, promote that two kinds of material cultures can both healthy nuisanceless growth, reach resource and culture utensil and rationally utilize, to promote the sustainable development of seawater buoyancy raft net cage culture.From the benefit of the angle holothruian cultures of economic benefit much larger than shellfish culture.Growth cycle between the two is almost few, but the economic worth of sea cucumber is much larger than shellfish, and preventing and kill off of stained thing will consume lot of manpower and material resources on the shellfish culture cylinder mould, and the then stained antithesis thing of sea cucumber is sea cucumber and good natural bait.