CATDOLL : CATDOLL: Why does the production of swimming crabs in the sea vary from year to year?

Why does the production of swimming crabs in the sea vary from year to year?

Experts said that it may be due to the influence of the marine environment. Crabs and shrimps have a short life cycle, both are annual, and are more "sensitive" to environmental changes than fish with a longer life cycle. When there are changes in marine environmental factors, such as salinity and temperature, the growth and production of swimming crabs will be greatly affected.

From the perspective of the marine food chain, due to the high international oil prices, before the fishing ban this year, many fishing boats in Zhoushan did not carry out large-scale fishing, which led to an increase in the resources of carnivorous fish such as octopus and monkfish, the "natural enemies" of crabs, and a decrease in crab production. After the full fishing season in September, if the production of dominant species such as octopus and monkfish does increase significantly, then this chain point can be verified to a certain extent.

Finally, the reduction in the production of swimming crabs cannot rule out the impact of overfishing. In April every year, a "crab mother" can produce hundreds of thousands of "crab babies". If fishing boats poach swimming crabs during the fishing ban, it will also greatly affect the amount of swimming crab resources.

"The increase or decrease in swimming crab production is the result of multiple factors. It is very complex and cannot be generalized in one sentence," the expert concluded.

There are several reasons for this, including environmental pollution, climate change, reduced aquaculture area, overfishing, etc. On the one hand, the aquaculture area of ​​swimming crabs in China has been declining year by year, and on the other hand, swimming crabs have high requirements for water quality. Water pollution will cause the death of a large number of swimming crabs.

With the worsening of marine environmental pollution in recent years, the per-hectare seawater aquaculture output of swimming crabs has also been declining. With the worsening of marine pollution along the coast of China, the habitat of swimming crabs has decreased and the number of swimming crab populations has decreased. Coupled with the overfishing of swimming crabs in the past, the catch of swimming crabs has declined year by year.