Cause analysis of resources change and reconstruction strategy of Larimichthys crocea Daiqu group in the East China Sea

The Larimichthys crocea Daiqu group in the East China Sea was once one of the most commercially important demersal fishes unique to China's coastal waters. It is now an important target for our country to restore and rebuild the resources of L. crocea. In order to clarify the influencing factors of the decline of its resources, and reveal the selectivity of its habitat and the reasons why the resources of the L. crocea are difficult to recover, this paper took the L. crocea fishing output in Zhejiang Province from 1950 to 2020 as a sample, and analyzed the correlation between the population number changes of the L. crocea Daiqu group and major fishery events, such as knocking operation and rounding up the overwintering group in the central fishing ground, by using index analysis method, which aims to trace the causes of the decline of large yellow croaker resources; The biological characteristics and evolution of L. crocea and its adaptability to habitat were described by comprehensive literature analysis. The results showed that: (1) the main causes of the decline and depletion of L. crocea resources were caused by several unreasonable development and utilization methods, such as knocking operation, catching the incoming fishes and overfishing the wintering grounds; (2) L. crocea has the characteristics of long life span, late sexual maturity, complex population structure, and strong habitat environmental selectivity, among which temperature, salinity, flow rate, substrate and feed organisms are the key environmental factors; (3) Due to overfishing, the life history of L. crocea deviated from the original selection position, but it still belonged to K selection game. (4) In addition to human factors (such as excessive fishing intensity), the main factors affecting the recovery of L. crocea resources may also be related to the k-biased life history and habitat selection of large yellow croaker. What’s more, this study also put forward the future protection and proliferation strategies of L. crocea from the perspective of biological characteristics and habitat environmental selectivity, which provides a decision-making basis for the restoration and reconstruction of L. crocea Daiqu group in the East China Sea.