Sea urchin rearing methods
Nursery culture Sea urchin reproduction in the summer, in the water temperature of 22 ~ 28 ℃, from the sea area to capture large individuals, the gonads of mature sea urchins, temporary 1 ~ 2 days, carefully remove the shell, the gonads on the anatomical plate, with a syringe to the gonads injected into the concentration of 0.5 equivalents of potassium chloride solution catalytic, and then let the seawater fully immersed in the cavity, can wait a few moments to discharge, sperm, and then the body can be used to feed on the sea urchin. Then let the seawater fully immersed in the body cavity, wait for a few moments to discharge the sperm and eggs. After the eggs are fertilized, the eggs are washed several times with filtered seawater and then put into the incubator to let the fertilized eggs develop. When the larvae turned out of the egg membrane, they were cultured at a density of 1 larva/cubic millimeter and fed with unicellular algae. When the larvae were first put in, fresh seawater (filtered) was added 20 cm per day, and when the water level was full, a filter rod wrapped with a sieve silk was used, to change the water, and when the larvae metamorphosed to juvenile sea urchins, the water could be changed directly by using a rubber hose. When the larvae develop to the 8 carpal stage and are about to end the planktonic period, they should be put into the attachment device (the same as the sea cucumber attachment device), so that they can attach, and then after 2 months of feeding, the shell diameter of the vertebrate sea urchins reaches 4.5 to 5 millimeters. It can be collected and then spread to the bottom of the sea for breeding.
Harvesting and processing Harvesting should be the most developed and full of sea urchin reproductive glands. Harvested sea urchins, the requirements of the gonads full, clear particles, pure color. Because of the different types and origins of sea urchins, the harvesting period is also different.
Morphological characteristics of sea urchins
The body of the sea urchin is spherical, disk-shaped or heart-shaped, without wrists. Endoskeleton fused with each other to form a solid shell, divided into three parts: the first part of the largest, by more than 20 rows of polygonal bone plate arranged into 10 belt area, 5 with the foot of the step zone and 5 without the foot of the foot of the step zone is arranged between the bone plate are warts and movable long spines. The second part is called the parietal system, located in the center of the anti-mouth surface, by the periproct (periproct) and five genital plates and five plates (ocular plate), each genital plate has a genital pore, there is a piece of the genital plate porous, the shape of the special, and as a sieve plate role; plate eye on each eye, the end of the spoke water tube from the hole out for the sensory apparatus; periproct on the anal part of the anus. The third part of the peristomal part, bit mouth surface, there are 5 pairs of mouth plate, regular arrangement, each mouth plate has a tube foot, around the mouth there are 5 teams of branching gills, for the respiratory organs. Most species have a complex chewing apparatus in the mouth, called Aristotle's lantern (Aristotle?s lantern), which is toothed and can chew food. Digestive tube long tubular, coiled in the body, to algae, hydroids, worms for food. More dioecious, individual development through the sea urchin larvae (long carpals), after metamorphosis into young sea urchins, after 1-2 years to reach sexual maturity.
Sea urchins are generally darker, such as green, olive, brown, purple and black.
How sea urchins reproduce
The vast majority of sea urchins are dioecious, with no difference in appearance, and some species are hermaphroditic. Gonads are located in the gallbladder shell between the step zone, when mature, very long, hanging in the body cavity, by two layers of body cavity epithelial cells, muscle and connective tissue **** with the composition. Each gonad has a very short reproductive duct that passes through the reproductive plate to open outside the body with a reproductive pore, where sperm and eggs are fertilized in seawater. Ovulation occurs several times a year. Breeding season is in the middle of June-July.
Development occurs through a free-swimming echinopluteus stage, which has 4-6 pairs of long wrists and is morphologically similar to a snake-tailed larva. After a few weeks of swimming and feeding, the echinopluteus sinks to the bottom, does not attach, and quickly metamorphoses into an adult, which is only about 1 mm. There are five pairs of tube feet on the oral surface, and the top plate of the antral surface is very large. Later, new tube feet are formed continuously from the mouth surface, and the top plate becomes relatively small, gradually developing into sea urchins. Fertilized eggs of some species can incubate eggs and larvae between the spines on the oral or antoral surface without a free-swimming larval stage, and leave the mother's body after developing into small sea urchins.
After three years of growth, the sea urchin reaches its mature stage and begins to fulfill the heavy responsibility of reproducing offspring. They are gregarious animals, in reproduction, it has a peculiar phenomenon, that is, in a localized sea area, like to gather together, once a sea urchin to the reproductive cells, whether sperm or egg discharge into the water, will be like a radio broadcast the message to every sea urchin in the vicinity, stimulate all sexually mature sea urchins in this area to discharge sperm or ovipositing. This strange phenomenon has been described as ? reproductive contagion?
Habits of Sea Urchins
Naturally timid, sea urchins will run away at the first sight of an enemy, but they cannot move very fast. Most sea urchins live on the bottom of the sea, preferring to live in the seaweed-rich intertidal zone below the sea area between the reef forest or rock crevice, as well as hard sandy and muddy shallow sea area, with the characteristics of light and day and night.
Sea urchins move in response to feeding: when food is plentiful, they may move as little as 10 centimeters per day. When food is scarce, they may move up to 50 centimeters per day. Sea urchins move by means of transparent, small, numerous and sticky tube feet and spines. The tube feet, similar to a starfish, grip rocks during movement, while the spines located on the underside lift the body of the sea urchin to help it move at will. They can always use the direction of the step band as a guide when moving without having to turn their head. When the sea urchin is turned upside down, its spines and tube feet can turn it right side up.
Sea urchins have a wide range of diets, with carnivorous ones feeding on worms, molluscs, or other echinoderms on the sea floor, and herbivorous ones feeding on algae, and others feeding on organic debris and animal carcasses.
The main value of sea urchins
Nutrition
Sea urchins feed on their gonads, which are also known as sea urchin eggs, sea urchin seeds, sea urchin yellow, sea urchin paste, orange in color, taste and smell, accounting for 8-15% of the total weight of sea urchins. Eicosapentaenoic acid contained in its gonads accounts for more than 30% of the total fatty acids, which can prevent cardiovascular disease. Sea urchin is not only a superior seafood delicacy, but also a valuable traditional Chinese medicine. The main nutrients of sea urchin eggs are lecithin, protein, riboflavin, thiamin, fatty acids and so on. Fatty acids contained in sea urchin eggs have a good effect on the prevention of certain cardiovascular diseases. Traditional Chinese medicine believes that sea urchin eggs are salty in taste and flat in nature, with the effect of softening and dispersing knots, resolving phlegm and swelling. Sea urchin is very easy to deteriorate after death. At the same time, sea urchin shells can also be made into handicrafts, some manufacturers also develop sea urchin food, sea urchin made of chilled sea urchin, alcohol sea urchin and sea urchin sauce. In addition, sea urchin extract Bonellinin (Bonellinin) has inhibited the growth of cancer cells.
Purchasing
Unlike clams, sea urchins are not as fresh as clams, which can be seen by tapping the shell. The main way to select sea urchins is to look and touch them.
1, look: look carefully, fresh sea urchin body spines are moving, the greater the amplitude of the movement, indicating that the better the freshness.
2.