Lobster is the largest of the shrimp family, of which the sheep embroidery lobster is the largest class of lobster. Lobster helmet wearing armor, "armor" is very hard, the head and chest with many spines, two long thorny tentacles, and ten stout feet. Lobster in addition to the spines on the head and chest, and then no other weapons, slow and clumsy, relatively easy to catch. Lobster lives in the warm ocean, it inhabits the seabed, hidden in the crevice of the reef during the day, only to come out at night to feed.

Lobster body length is generally 20-40 centimeters, weighing 500 grams up and down. There are eight species of lobsters in China, and the largest, the Fairview Lobster, can weigh up to 5 kilograms.

Lobsters include two different broad categories, lobsters and crayfish. Lobsters are all marine, while crayfish are both marine and freshwater. Sea-produced crayfish known as sea crayfish or crayfish, freshwater known as crayfish or? mayflies, but abroad they are collectively known as lobsters.

Lobster (also known as spiny lobster or rock lobster) live in the warm ocean of the rocky reefs in shallow water, mainly distributed in India - the western Pacific region. They move slowly, often lurking in the seabed during the day in the crevices of the rocky reefs, night out to forage for food. When their eggs hatch, the larvae are in the shape of a leaf, so they are called "leafy larvae". Leafy larvae to float in the ocean for more than half a year, after several molts to become a lobster-like, after a period of swimming life and then settled on the seabed, line crawling life.

Norwegian crayfish produced in the north of the Atlantic Ocean, as well as Northern Europe, North America, some species of crayfish produced in the individual is very large. 1934, the deep-sea trawler "Hesburgh" in North America to pick up a 1.22-meter-long (even the two chelipeds, including) of the cheliped lobster, weighing 19 kilograms, is now on display in the United States, the Museum of Science in Boston, is the world's largest collection of lobsters!

The crayfish has three pairs of chelipeds, especially the first pair of chelipeds especially thick, very easy to distinguish from lobsters, because lobsters do not have chelipeds. American crayfish and European crayfish crayfish chelicerae weigh about half of their body weight, and some even account for 2 / 3 of their body weight. crayfish and lobster is also a very important difference, is that the crayfish larvae and adult differences are very small, that is to say, after the eggs hatch out of the juvenile very much like the adult, did not go through the leaf-shaped juvenile stage.

Morphological Characteristics

(1)Appearance

The body is large and cylindrical, and is the largest shrimp in the world. The carapace is firm and thick, the cephalothoracic armor is slightly laterally flattened, and the anterior lateral margins are not fused to the anterior plate of the mouth, nor are the lateral margins fused to the thoracic ventral armor and the bases of the thoracic limbs except in the family of crayfish. Nuchal groove conspicuous. 1st antennae shorter and smaller, double whipped. 2nd antennal with more developed scales. all 3 pairs of jawed feet exopodial. The footsteps are all unibranchial, the first 3 pairs of chelipeds, of which the first pair is particularly strong and thick, so it is also known as crayfish. The last 2 pairs of legs are simple and claw-like. The gills are filiform.

(2) appendages

Lobster head with 3 pairs of tentacles, tentacles near the head is thick, the tip is small and pointed. A pair of tentacles at the outer edge of the head is particularly thick and long, generally longer than the body length of 1 / 3; in the middle of a pair of long tentacles for two pairs of short tentacles, the length of about half of the body length. When perching and crawling normally, all six tentacles are stretched forward; if frightened or attacked, the two long tentacles are bent toward the tail to prevent the tail from being attacked.

The thorax has 5 pairs of steppers, the 1st-3rd pairs of steppers end in pincers, the 4th-5th pairs of steppers end in claws. The second pair of footsteps is particularly developed into a very large chelipeds, the male chelipeds are more developed than the female, and the male lobster has a bright red film on the front outer edge, very conspicuous. Females do not have this red film, so this becomes an important feature of male and female distinction.

The tail has five powerful discretionary tail fan, the female shrimp in the egg holding period and incubation period, the tail fan is bent inward, crawling or by the enemy, in order to protect the fertilized eggs or baby shrimp from damage.

Habitat

①Benthic

Lobster like to live in water plants, branches, stone gaps and other hidden things. The shrimp day and night, do not like bright light. Under normal conditions, during the day, more hidden in the water deeper or in the concealment, rarely active, the evening after the sun goes down began to move, more gathered in shallow water crawling for food or looking for a mate. If frightened, quickly flee back to deep water. The shrimp like to crawl, do not like to swim, foraging and activities when crawling forward, frightened or encountered enemies quickly backward, jumping to avoid.

② water

Lobster has a strong tendency to water flow, like new water, live water, against the water upstream, and like to live in clusters. In the breeding pool often gathered in groups around the inlet. Heavy rain, the shrimp can reverse the flow of water on the shore for a short stay or escape, the water environment is not suitable will also climb the shore to live, so the farm site should have anti-escape fencing facilities.

3 aggressive

Lobster aggressive nature, in the feed shortage or fight for habitat cave, often appear to be strong, bully the weak, bully the phenomenon of fear of the big small.

Larvae have a strong regenerative capacity, the loss of part of the 2nd molt regenerate part of the molt, several times after the molt will be restored, but the newborn part is shorter than the original. This self-cutting and regenerative behavior is a protective adaptation.

4 Digging holes

Lobsters like to dig holes and are good at it.

First, the depth and speed of burrowing

The depth of lobster burrowing is a key factor in determining the degree of damage. According to our field measurements of 35 cases of lobster burrows, the depth of most of the burrows in the 50-80 cm, about 70% of the measured burrows, some of the depth of more than 1 meter, we measured the longest one burrow up to 2.1 meters. Typically, lobster burrows that are oriented horizontally in a planar direction are the only ones with depths greater than 1 meter, while burrows that are oriented vertically downward in depth are generally shallower. Lobster burrowing speed is very fast, especially in the put into a new living environment is especially obvious. Dafeng lobster test pool A, put into the lobster after a night of observation, in sandy soil conditions, most of the lobsters dug a new hole depth of more than 30 centimeters.

Second, the location of lobster burrows

Lobster digging holes in the hole location is usually chosen at the level, but this choice is often due to changes in the water level and make the hole higher or lower than the level, so generally 20 centimeters above and below the surface of the water, the lobster holes most. However, the location of lobster digging hole selection is not very strict, in our test base, in the water on the ridge, water slopes, and shallow areas of the bottom of the pool are lobster burrows, more concentrated in the lush water plants.

Third, the survival of the environment on the impact of lobster burrowing

Water substrate conditions on the lobster burrowing effect is more pronounced in the lack of organic matter in the substrate of sandy soil, lobster burrowing phenomenon is more, while the hard soil burrowing is less. In the water quality is more fertile, more bottom silt, organic matter-rich conditions, lobster burrows significantly reduced. However, the number of lobster burrowing increased significantly during the breeding season, regardless of the survival environment.

Adaptation

①Environmental requirements lobster has a strong ability to adapt to the environment, a variety of water bodies can survive, whether it is lakes, rivers, ponds, ditches, paddy fields can survive, and even in some of the fish difficult to survive in the water body can also survive. Lobster resistance to low oxygen capacity is strong, in the water body of the lack of oxygen under the environment it can climb ashore for gill respiration in order to maintain survival. Water quality PH value in the range of 5.8-9, dissolved oxygen below 1.5mg / L can still survive normally. Normal growth requires more than 3ml / L of dissolved oxygen.

② water temperature

Lobster growth of suitable water temperature of 24 ℃ -30 ℃, when the temperature is lower than 20 ℃ or higher than 32 ℃, the growth rate declined, the water temperature is 15 ℃ below the survival rate of juveniles is extremely low. Feeding waters day and night temperature difference can not be too large, baby shrimp young shrimp day and night temperature difference should not exceed 3 ℃, adult shrimp do not exceed 5 ℃, otherwise it will cause significant losses.

In the Pearl River Delta and coastal areas of South China, generally can be natural overwintering, in order to prevent the attack of a large cold wave, can be placed in the wintering shrimp in deeper pools, and in the north-west corner of the pool to take the wind wall or cold shed. Embryonic development of suitable water temperature of 22 ℃ -32 ℃, if you keep 28 ℃ -30 ℃, incubation time can be greatly reduced.

③ PH value

Lobster suitable PH value range of 5.8-9, but in the breeding incubation period requires PH value of 7.0 or so, dissolved oxygen 3mg / L or more. However, it is very resilient and can live in some domestic sewage, light industrial wastewater, and is also distributed in field ditches and channels in pesticide application areas.

Food and growth

1. Food

Lobster is a partial animal omnivore, but the food in different stages of development slightly different. Just hatched larvae to its own survival of the yolk for nutrition, and soon thereafter will feed on rotifers and other small zooplankton, as individuals continue to grow, feeding on larger zooplankton, benthic animals and plant debris, adult shrimp both plants and animals, the main food plant debris, animal carcasses, but also ingested water earthworms, rocking mosquito larvae, small crustaceans and a number of aquatic insects. In the case of artificial culture, the larvae can be fed to the articulate larvae, spirulina powder, etc., adult shrimp can be fed with artificial feed, or artificial feed, supplemented by animal and plant debris.

2. Molting and growth

Lobster is through the molt to achieve growth, after the molt of the new body shell in 12-24 hours after hardening. In the water temperature of 25 ℃ -30 ℃ conditions, feeding 6-8 months, weight up to 60-150 grams. Lobster growth trend is: from hatching to the weight of 20 grams of this stage, the growth rate is accelerated growth; in the stage of reaching 50-100 grams, the rate of its growth to remain at a relatively stable level, more than this stage, the growth rate will be a declining trend. Thus forming an inverted u-shaped growth curve. Molt long molt and reproductive molt two kinds of juvenile shrimp from the mother, quickly into the first molt, replaced with soft wrinkled new skin, and rapid growth of water intake, this is the growth of molt, by the larvae to adult **** molt 11 times. Female shrimp sexual maturity will begin to reproductive molt, and then each time before mating and spawning should be reproductive molt.