Prey Abundance Regulating the Response of an Important Marine Eel Species Conger Myriaster Growth to Water Temperature

Whitespotted conger (Conger myriaster) is a commercially important species in East Asia but the fisheries stock has drastically declined in recent years. Environmental changes are assumed to have profound impacts on the growth pattern of this species, yet the mechanisms that regulate growth remain poorly understood. Here we used otolith measurements to establish growth chronologies of 9-year period (2010–2018) for whitespotted conger in the Yellow Sea and evaluated the effects of environmental variables on the growth pattern. Linear mixed-effects models were used to explain growth variation with abiotic and biotic environmental variables, including seasonal water temperature, prey availability, and population density, and to assess age-dependent responses in growth and the interactions between abiotic and biotic factors. The results indicated that the growth of whitespotted conger positively correlated with spring sea bottom temperature (March-May) and prey per capita, and the influence of prey availability became larger with increasing ages. The model detected significant negative interactions between sea temperature and prey availability, indicating a higher degree of temperature-dependent growth when prey availability was low. Our findings imply that the growth of whitespotted conger is less likely to be influenced by food availability when the spring water temperature is high in the Yellow Sea, and a combination of cold spring and low food availability may result in substantial constrained growth. This study provided the first evidence for the joint effects of abiotic and biotic factors on the growth variation of whitespotted conger, and the information may contribute to sustainable management policies.