Temporal changes in the diet composition of Shorttail Yellownose skate, when exposed to overfishing conditions in northern and central Patagonia, Argentina

Abstract

Due to their relationship with prey availability, elasmobranchs with an opportunistic diet can serve as indicators of changes in the marine community, thereby enhancing our understanding of the health of marine ecosystems. In this study, the Zearaja brevicaudata’s trophic ecology was studied, by analysing its stomach contents, aiming to provide evidence of long-term changes in diet resulting from shifts in the structure of the Argentine Patagonian marine community in response to fishing pressure. Changes were evaluated according to catch area, predator size, sex, maturity over time. Moreover, the relationship between Zearaja brevicaudata’s dietary shifts and the fishing effort of Merluccius hubbsi was investigated. Our results suggest a gradual replacement of the main prey species with lower trophic level species. Although no correlation was found with fishing effort, the diet of Z. brevicaudata over time reflected changes similar to those associated to the fishing exploitation of M. hubbsi in the Patagonian system. In this context, the Z. brevicaudata’s diet emerges as a valuable tool for monitoring and assessing changes in the marine community. By serving as an indicator, Z. brevicaudata’s diet provides crucial insights into the conservation status of the marine ecosystem, enabling informed management and conservation efforts.