Evidence of deep-sea trophic resource partitioning between the glowbellies Acropoma hanedai and A. japonicum near Southwestern Taiwan
摘要
The occurrence of resource partitioning in deep-sea fishes via depth partitioning or differences in prey selection is known from several studies despite previous suggestions that deep-sea fishes are usually generalist feeders. The glowbellies Acropoma hanedai and A. japonicum co-occur and are caught together in the lower epipelagic and the upper mesopelagic during fisheries operations off southwestern Taiwan. Our goals for this study were to describe the diet of A. hanedai and compare it to the diet of the better studied A. japonicum. We examined stomach contents in specimens collected by commercial fishers near Donggang, Taiwan, in May 2016 and February 2019. Acropoma japonicum and specimens of both species collected in May 2016 were significantly larger than A. hanedai and specimens collected in February 2019. Acropoma hanedai more commonly had teleost stomach contents in May 2016 and caridoid crustaceans in February 2019, with the opposite pattern in A. japonicum. The temporally differing diet between species remained statistically significant even after statistically accounting for the effects of predator size. This is likely an example of temporally variable resource partitioning between species of deep-sea fishes.