Discarded but Not Dismissed: A Comprehensive Study of the Feeding Habits of the Brown Comber (Serranus hepatus, (Linneaus 1758)) in the Gulf of Cádiz (NE Atlantic)

Abstract

The brown comber (Serranus hepatus) is a small benthopelagic species with no commercial value, primarily caught by bottom trawls as a by-catch. In this work, we studied the feeding habits of this species. For this purpose, samples were obtained from the trawl fleet within the different editions of the ECOFISH project carried out between 2019 and 2022. A total of 1534 individuals were analyzed. In the diet analysis, various factors were considered, such as the season, the depth, and the time of day of the capture, as well as the size range of the individuals caught. For the feeding analysis, different indexes were calculated, such as the vacuity index (%Vi) and index of relative importance (%IRI). The size range of the specimens was between 3.2–16.3 cm, and the weight was between 1.02–39.73 g. Of the stomach content analyzed, 49.7% of the stomachs were found to be empty. The resources with the greatest importance in the diet of the brown comber were from the crustacean group, especially mysidaceans and decapods. There were differences in the diet according to season, depth, and size; however, there was no variation in diet by the time of day.