Shellfish is a category of mollusks, and there are many varieties of shellfish.Therefore, there are some differences in the reproductive methods they use:
1. Dioecious: Many animals in shellfish are dioecious, such as Monoplacophora, Polyplacophora, Cephalopoda and so on.Most of the reproductive methods used are oviparous, but the specific way of sperm and egg combination is different.Some shellfish lay eggs and sperm directly in water, allowing them to fertilize, which is the way American oysters do, and they can lay a large number of eggs at a time, sometimes up to 100 million.Some shellfish eggs are fertilized and hatched in vivo, the snail is used in this way of reproduction, they can produce a relatively small number of eggs each time, only a few dozen; Snails, on the other hand, can only produce 3-5.
2. Hermaphrodite: Some shellfish are hermaphrodite themselves. All the shellfish of pulmonate snails are hermaphroditic. In addition, some shellfish such as opisthobranchia, prosobranchia and bivalves are hermophrodite.The way they reproduce is that two individuals fertilize each other.
The breeding of shellfish has requirements for the surrounding environment. Generally speaking, the breeding efficiency is higher when the temperature is suitable.When the temperature rises in the spring, the shellfish will begin to reproduce.By May and June, it can be said to be the peak period of shellfish reproduction.However, the breeding time of shellfish in different areas will also vary, for example, in very northern areas, shellfish will start to breed in large numbers later.
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