Biological characteristics Hemorrhoids are bivalve molluscs belonging to:
Lamellibranchia,
From the order of Eulamellibranchia,
Heterodontta,
Corbiculidae,
Corbicula,
Hemorrhoids live in brackish water and water, preferring habitats with slow-flowing water, waterless grasses, sand mud bottoms, and water depths of about 1.5m in the water environment. Both are dioecious in brackish water. Both dioecious and hermaphroditic in freshwater. Hermaphroditism has a sexual phenomenon.
The peak of natural reproduction is from May to August and fertilization occurs in the sacral cavity. In the breeding season, the male-male ratio is generally 1:1. In other seasons, males are more likely than females. The gonads are distributed over the axe, on both sides of the visceral mass, and in the intestine. Male and female differences in shape are difficult to identify, mainly from the color of the gonads. Female gonads are purple-black, mature grape-like. Remove the egg can be dispersed. Male gonads are milky white and mature semen with white slurry.
The river raft breeds differently than the river raft. Hemorrhoids are juvenile with parasitic characteristics. The river raft has juvenile and oviparous types, but has no parasitic characteristics. It is directly produced into water and the embryo is developed into seedlings in water. Hemorrhoids generally begin to mature at 2nd instar, 4th instar begins to decline, and 2 to 3 instar gonads are excellent. The homozygous fertilized eggs develop into D-shaped larvae before they are excreted from the body. The heterozygous fertilized eggs are directly excreted from the body. In the autumn, the coriander can grow to a shell length of 0.5 cm and a grain weight of about 0.5 g.
When the water temperature in winter is lower than 5°C, the river clams stop feeding and growing. In spring, the water temperature rises and the river clams enter a new growth period. The above-mentioned intermittent growth continues to increase the growth of concentric circles on the surface of the rim. When it grows, the veins are sparse and pale, and the veins are dense and dark at the time of stopping. The morphology is similar to that of other shellfish (such as grasshoppers). Observe the growth and age of the river otters.
Hemorrhoids generally reach sexual maturity when the shell length is 1.2cm. The growth time is 2 years. It can grow to shell length 2cm in 3 years. At this time, it is the most suitable fishing specification. However, the current market uses 1.8cm to 2.6cm shell length. Merchandise.
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