Ontogenetic shifts and feeding strategies of 7 key species of Gadiformes in the western Mediterranean Sea

The trophic ecology of 7 key species of Gadiformes, the silvery pout (Gadiculus argenteus), Mediterranean bigeye rockling (Gaidropsarus biscayensis), European hake (Merluccius merluccius), blue whiting (Micromesistius poutassou), Mediterranean ling (Molva macrophthalma), greater forkbeard (Phycis blennoicles), and poor cod (Trisopterus minutus), in the western Mediterranean Sea was explored. A total of 3192 fish stomachs were examined during 2011-2017 to investigate ontogenetic shifts in diet, trophic interactions (both interspecific and intraspecific), and feeding strategies. The results from applying multivariate statistical techniques indicate that all investigated species, except the Mediterranean bigeye rockling and poor cod, underwent ontogenetic dietary shifts, increasing their trophic level with size. The studied species hold different trophic positions, from opportunistic (e.g., the Mediterranean big-eye rockling, with a trophic level of 3.51) to highly specialized pisciyore behavior (e.g., the Mediterranean ling, with atrophic level of 4.47). These insights reveal 4 different feeding strategies among the co-occurring species and size classes in the study area, as well as the degree of dietary overlap. Such information on ecological patterns within a fish assemblage, including species interactions, is often requested by those who aim to implement ecosystem management. Therefore, these findings can be used to improve management of sustainable fisheries in this region.

Automated summary

The study explores the trophic ecology of 7 key species of Gadiformes in the western Mediterranean Sea, finding that most species undergo ontogenetic dietary shifts, increasing their trophic level with size. Different feeding capabilities and strategies were observed among these co-occurring species in the study area, providing valuable information for improving the management of sustainable fisheries in the region.