a kind of sea cucumber
Stichopus nigricans
The environmental impact is 1. Generally, it is brown or chestnut, and individual colors at the bottom of the rock are darker.
2. Most of the algae are green, white, reddish brown and purplish brown.
3. The number of bone spurs and water temperature at the bottom of the rock are higher than those at the bottom.
4. The water temperature of the bottom material is high, the meat thorn is thick, and the individual is relatively large.
External form: the body is flat and cylindrical, with slightly thinner ends, and the body is divided into quilt and abdomen.
Rear part of the car body: divided into two spokes (step area) and three middle spokes (step area).
There are 4 ~6 rows of conical barbs (also called wart feet) on the back, which are deformed tube feet.
Ventral surface: relatively flat, with three spokes and two middle parts,
The tube foot, with numerous small protrusions on the whole abdomen and sucker at the end, is roughly arranged in three irregular longitudinal bands on the abdomen.
Tentacles: Located on the ventral surface of the front end of the body, there are usually 20 bamboo-like tentacles arranged in a ring around the mouth. Stichopus japonicus sends food into its mouth by sweeping tentacles.
Mouth: located in the center of perioral membrane, the entrance is annular.
Anal: Located at the back of the body, slightly off the back. Genital foramen: located in the radial part of the front back from the head 1 cm ~ 3 cm, it is concave and has a deep pigment.
It is obvious in the breeding season, and it is difficult to see this hole except in the breeding season.
Body length: generally 20 cm, about 4 cm in diameter and up to 40 cm in length.
Note (1) The epithelial layer is composed of a single layer of epidermal cells, which are wrapped around the body surface for protection. Epidermal cells can secrete mucus and lubricate the body.
(2) Under the cortex, there is a thick glial cortex, mainly connective tissue.
The quality of sea cucumber mainly depends on the thickness and fullness of cortex.
Numerous tiny calcareous bone fragments are buried between the epithelial layer and the cortical layer. Calcareous bone fragments, the shape of which changes with age. Table-shaped bone block of young ginseng
The tower is thin and tall, with a large chassis and smooth surroundings; The tower of table-shaped bone fragments of the elderly Stichopus japonicus becomes low or disappears, leaving only a small perforated plate.
Natural distribution 1. Temperate and frigid species
2. Mainly distributed in the shallow sea of the North Pacific Ocean, including Japan, South Korea, the Russian Far East coast and the northern coast of China.
3. Dalian, Lushun and Changhai in Liaoning (Dachangshan, Guanglu and Zhangzi are more distributed) and the anchored islands in Suizhong.
Shandong Changdao, Longkou (Longkou Bay, Sangdao), Laizhou (Sanshan Island), Penglai, Yantai, Weihai, Rongcheng, Jimo, Qingdao, Jiaonan and Japan.
According to Shijiusuo and Qian Shan Island (the southernmost part of the natural distribution of Stichopus japonicus), Beidaihe, Hebei Province.
Sea cucumber movement 1. In places with rich bait and suitable environment, the range of activities is small.
2. In the absence of bait and poor living environment, large-scale movement can be carried out, and some individuals even relax and go with the flow.
3. In the case of artificial feeding, the body floats in the air near the water surface, and this floating phenomenon mostly occurs at night or in the early morning.
4. The activity ability and foraging activity of Stichopus japonicus in autumn are not as good as that in spring.
Water temperature 1 hour. Below 3℃, the food intake decreases, the activity is slow, and it gradually enters a semi-dormant state.
2. The suitable water temperature is 5 ~ 65438 08℃
3. The optimum water temperature is 10~ 17℃
4. 17.5 ~ 19℃ has adverse effects on the ingestion and digestion of ginseng.
5. When the temperature exceeds 20℃, although young ginseng doesn't sleep in summer, it still eats a lot, but its digestion and absorption rate begin to decline.
6. If it exceeds 23℃, it will adversely affect its growth.
At 7.26℃, the natural distribution area of Stichopus japonicus rarely exceeds 26℃
8. When the temperature exceeds 30℃, the body weight tends to decrease, and Stichopus japonicus can adapt to the artificial ecological environment.
Salinity is 1. The application range is 26.2~39.3.
2. All the auricular larvae died after 1 hour, and nearly half of them died after 20 hours and 12 hours.
When the temperature of young ginseng was 65438 05℃ and the salinity was above 25, no dead individuals were found.
When the water temperature is 65438 05℃ and the salinity is below 20, dead individuals appear.
The water temperature is 20~25℃, the salinity is above 20, and there are no dead individuals.
Body length 5 mm, water temperature 65438 05℃, salinity above 20, no dead individuals.
When the water temperature is 20~25℃ and the salinity is above 15, there are no dead individuals.
PH value: 7.9~8.4
The respiratory tree in the breathing sea cucumber is the main organ for breathing. In addition, the skin and tube feet also have the function of breathing.
The oxygen consumption of Stichopus japonicus is different at different temperatures. In the temperature range of normal activities, the oxygen consumption of adults is 0.4 ~ 0.8 ml/hour.
Exercise mainly depends on the expansion and contraction of the abdominal dense tube foot, body striated muscle and longitudinal muscle, and carries out slow and rhythmic exercise.
Tidal current and wind waves 1. Shallow sea and inner bay with gentle tidal current, slow velocity and less wind and waves.
Water depth 1. Most of them are distributed within the water depth15m, and the maximum distribution depth can reach more than 35m.
2. In the same sea area, the distribution depth is related to age, and juvenile ginseng is mostly distributed in shallow water, and gradually moves to deep water with age.
3. Water depth: intertidal wall weight: 2.5 ~ 22.5g, with an average of 9.6g..
Water depth: 4.5 ~ 6.0m Body wall weight: 17.5 ~ 102.5g Average: 45.8g
Water depth: 9.0 ~10.5m Body wall weight: 37.5 ~ 207.5g Average: 87.9g.
Water depth:12.0 ~13.5m Body wall weight:102.5 ~187.5g Average value:150.0g.
Water depth: 13.5 ~ 15.0m Body wall weight: 122.5 ~ 232.5g Average:180.6g.
The sediment is 1. When the silt content exceeds 20%, there are few sea cucumbers.
When the mud content exceeds 27.8%, Stichopus japonicus is not distributed.
Mud content below 10% (mainly sand, mixed sand, large sand, less fine sand and silty sand) is the most suitable habitat for Stichopus japonicus.
This is related to the natural weak resistance of Stichopus japonicus to natural enemies and seeking asylum and protection. Therefore, in the artificial cement pond culture mode, Stichopus japonicus gathers angles and climbs the wall.
This is also the case, which is a normal phenomenon. It is not recommended to change its lifestyle and drive Stichopus japonicus off the pond wall.
2. The content of organic matter and sulfide deposits is high, but the content of sulfide is low, which is suitable for the distribution of sea cucumber.
3. Reef, algae and algae provide hiding and habitat for Stichopus japonicus, such as storm and summer sleep.
Conducive to the diffusion of biological bait
The formation of local vortex is beneficial to the settlement of organic particles.
4. Rocks with different shapes and sizes are staggered, forming many gaps and holes, and the effect is good.
Flat reef and Kyoho reef have smooth surfaces, few gaps and no holes, which do not have the three functions of fishing reef and are rarely distributed.
The definition of primary productivity: Green plants (benthic diatoms, phytoplankton, macroalgae and kelp) synthesize carbohydrates per unit water surface and per unit time.
The ability of things
Main functions: The main synthetic carbohydrate is phytoplankton.
The primary productivity is higher and the distribution of Stichopus japonicus is better.
Feeding habits (omnivore) 1. Microorganisms (benthic diatoms, phytoplankton, protozoa, copepods, snails and bivalves)
2. Organic debris (large algae, kelp debris, molting debris of shrimps and crabs and various animal and plant carcasses)
3. Bacteria are the main food for Stichopus japonicus.
More than 70% of the energy requirement of Stichopus japonicus comes from bacteria.
The number of bacteria attached to the substrate of young ginseng is often large, and the nutritional price of young ginseng is high.
4. Sediments, gravel and shell fragments
5. Use dissolved organic matter directly from the surrounding seawater.
Feed depth: several millimeters
Feeding choice: there are both silt and sand, and the sediment they eat is basically the same as that in their habitat.
The food in the digestive tract of juvenile ginseng with a body wall weight of less than 2.5 grams is mostly benthic diatoms and organic debris except for a small amount of sediments.
With the increase of individuals, the proportion of food and sediment in the digestive tract also increases.
Digestion time: feeding around the clock, the digestive tract can be full of bait 1. 14 times a day, often full.
The food intake at night is greater than that during the day, accounting for about 79% of the daily food intake.
Digestibility: the consumption of natural bait is per gram of body weight 1.40g/ day and night (estimated by net weight after water removal).
Food intake: protein content is low, such as algae debris, sea cucumber with large food intake, and coarse and scattered feces.
Protein is high in content, such as snails and crab crumbs, and the food intake is small, and the feces are fine and sticky.
Feeding temperature: the water temperature is suitable and the food intake is large.
The water temperature is not suitable, and the food intake is reduced.
Don't eat when you sleep in summer.
The bigger the individual is, the more obvious the temperature response is, but the young ginseng is not obvious, especially the adult ginseng.
The change of food intake with water temperature is consistent with the change of digestive tube weight.
Definition of summer sleep: when the water temperature rises above 20℃, it moves to rocks and grass with deep seawater, and cannot eat or move. When the water temperature drops below 20℃, it comes out to exercise or eat again.
Object: Individuals who weigh more than 20 grams will have summer sleep.
Critical temperature in youth: no summer sleep.
1 year critical temperature: 24℃, weight loss rate of 52.8%.
2-year critical temperature: 23℃, weight loss rate of 39.7%.
3-year critical temperature: 22℃, weight loss rate of 45.5%.
Date: Late June (from summer to around) to early June (from around cold dew) in Shandong coastal areas.
From the middle and late August to the end of 10 (after the first frost)
Changes: During summer sleep, the digestive tract shrinks into thin lines, and the thickest part is less than1mm.
Definition of excreting internal organs: after intense stimulation, internal organs (stomach, intestine, respiratory tree, dorsal vascular plexus, gonads, etc. ) excreted from the body, commonly known as "vomiting intestines."
Unable to eat after defecation.
The sharp rise or fall of temperature, physical and chemical stimulation such as sewage, etc., can easily lead to the excretion of sea cucumbers.
Regeneration: after barb removal, small protrusions appear in 5-7 days, and completely regenerate after 30 days.
When the antenna was removed, the wound healed in a protruding way after 7 ~ 10 days, and regenerated into the antenna with the same length after 25 ~ 30 days, which could support normal feeding activities.
Incision of the back or abdomen with a length of 2 ~ 4 cm can completely heal itself after 5 ~ 7 days.
Stichopus japonicus can be cut into two sections, and part of the wound can be healed in 5 ~ 7 days, but there are also many cases where it can't heal normally and lead to death.
Autolytic Stichopus japonicus will melt if it leaves seawater for too long.
Propagation of Stichopus japonicus 1 Gonadal development period: rest period, proliferation period, growth period, maturity period and expulsion period.
2. Breeding temperature: 15~20℃
Time: Lunan from the end of May to the end of June.
From mid-June to mid-July in northern Shandong
Dalian sea area from early July to early August.
3. The age of sexual maturity is 2 years old, the smallest individual with sexual maturity is 1 10g, and the body wall weight is 60g.
4. The spawning amount contains about 200,000 eggs per gram of mature ovary.
Stichopus japonicus laid eggs many times, with an average spawning amount of 6.5438+0.0000 ~ 2 million.
Pre-embryonic development of ontogeny of Stichopus japonicus: genesis, maturation and fertilization of germ cells
Embryo development: cleavage, blastocyst stage, gastrula.
Postembryonic development: auricle larvae (small ears, middle ears, big ears)
Conformal larva
Five tentacles
Young ginseng
Sea cucumber has few enemies.
Seagulls can eat some intertidal sea cucumbers.
Stichopus japonicus was found in the stomachs of salmon and trout that swam back in summer looking for bait.
Some kinds of starfish and crabs can prey on young ginseng less than 3 cm long.
Perch and goby pose a certain threat to sea cucumber seedlings, especially submerged sea cucumber seedlings released into culture areas.