Seasonal feeding patterns of Atlantic bluefin tuna (Thunnus thynnus) in the Strait of Gibraltar

José Luis Varela; Irene Carrera; Antonio Medina

doi:10.1016/j.marenvres.2019.104811

Seasonal feeding patterns of Atlantic bluefin tuna (Thunnus thynnus) in the Strait of Gibraltar

Mar Environ Res. 2020 Jan:153:104811. doi: 10.1016/j.marenvres.2019.104811. Epub 2019 Oct 4.

Authors

José Luis Varela¹, Irene Carrera², Antonio Medina²

Affiliations

¹ Departamento de Biología. Facultad de Ciencias del Mar y Ambientales, Campus de Excelencia Internacional del Mar (CEI·MAR), 11510 Puerto Real, Cádiz, Spain. Electronic address: joseluis.varela@uca.es.
² Departamento de Biología. Facultad de Ciencias del Mar y Ambientales, Campus de Excelencia Internacional del Mar (CEI·MAR), 11510 Puerto Real, Cádiz, Spain.

PMID: 31606142
DOI: 10.1016/j.marenvres.2019.104811

Abstract

The Strait of Gibraltar (SoG) houses a large diversity of marine species including large pelagic animals that use this area as permanent or temporary habitat. In particular, the SoG is home to a population of adult and sub-adult Atlantic bluefin tuna (Thunnus thynnus) that occurs there for most of the year. To gain further insight into the life history of this ABFT population, seasonal feeding patterns were investigated combining stomach content analysis (SCA) and stable isotopes analysis (SIA) of muscle and liver tissues. Our results reveal seasonal variations in feeding patterns, which are evidenced by a significant shift in the diet composition and the highest food consumption rates that take place in spring, prior to the spawning season. These changes in feeding habits are consistent with the varying energetic needs along the species' annual biological cycle. The present observations confirm the SoG as an important foraging ground for ABFT resident populations and may have further implications for the management of the resource.

Keywords: Scombridae; Stable isotope analysis; Stomach contents; Strait of Gibraltar; Trophic biology.