Maria Valls, Maria Teresa Farriols, Beatriz Guijarro, Enric Massutí, Francesc Ordines, 2025. Protecting an area from bottom trawling affects trophic relationships in demersal species. ICES Journal of Marine Science, Volume 82, Issue 9, September 2025, fsaf161. https://doi.org/10.1093/icesjms/fsaf161

Abstract: This study examines how protecting the Site of Community Importance Menorca Channel (western Mediterranean) from bottom trawling affects the feeding behaviour of commercially exploited species. We examined taxonomic diet composition, prey quality (caloric value) and stable isotope signatures (δ¹³C and δ¹⁵N) across protected, moderately fished, and heavily trawled areas. Fish species Mullus surmuletus and Serranus cabrilla benefited from protection by consuming more high-energy prey resulting in higher caloric intake. Other species, such as Chelidonichthys lastoviza, Scorpaena notata, and Octopus vulgaris, showed more variable or limited responses, due to opportunistic feeding habits or prey preferences less affected by trawling. The combination of stomach content analysis and prey calorimetry provided better insights into energy intake than prey composition alone, which may miss short-term or fine-scale dietary changes. δ¹⁵N revealed no clear overall shifts in trophic level after protection from trawling, but isotopic niche width did vary, reflecting different foraging strategies and habitat use. The relationship between body size and trophic level was evident in protected areas for M. surmuletus and C. lastoviza, suggesting ontogenetic dietary shifts supported by increased prey availability. Overall, the study highlights species-specific trophic responses to fishing closure and suggests that diet tracing methods should be combined to better understand the ecological effects of marine protected areas.

Keywords: stomach contents, stable isotopes, prey abundance, prey caloric density, marine protected areas

< Prev		Próximo >