Large and Small Yellow Croakers Feeding and Living Together Make Large Yellow Croaker Population Recovery Difficult: A Guild Perspective

In recent decades, China's large-scale stock enhancement programs to restore the collapsing large yellow croaker (Larimichthys crocea) fishery resources have not yielded the desired results, and a comprehensive analysis of the underlying reasons for this problem is required. Based on small yellow croaker (Larimichthys polyactis) catch survey data obtained from 15 fishing ports along the coast of the East China Sea, we examined the proportion of large yellow croakers mixed in the small yellow croaker catch and their biological parameters. In addition, we analyzed the differences in the intestinal microbiota and feeding ecology between these two species to explore the reason why the stock enhancement program failed to achieve the desired outcome. The results show that there is a high likelihood of the two species appearing in each other's ecological niches, and there is a significant overlap in their dietary ecology. They may cohabitate and form a guild. The fishing season targeting the small yellow croaker indirectly catches the large yellow croaker population, which puts huge fishing pressure on large yellow croaker resource and shows obvious overfishing. Therefore, it is necessary to optimize and adjust the fishing ban policy and stock enhancement strategies, appropriately reducing the fishing intensity after the fishing ban to facilitate the effective accumulation of resource replenishment effects during the fishing ban period, thus effectively restoring wild large yellow croaker resources.