RT journal article
T1 Trophic interactions between bullet tuna (Auxis rochei) and frigate tuna (A. thazard) in the Gulf of Cadiz
A1 Varela Fuentes, José Luis
A1 Asensio Regidor, María Esther
A1 Borrego-Santos, Ricardo
A1 Laiz Carrión, Raúl
A1 Medina Guerrero, Antonio
A2 Biología
AB Bullet tuna (BLT), Auxis rochei, and frigate tuna (FRI), Auxis thazard, are globally exploited wide-ranging  species. These anatomically similar tunas may share pelagic habitats in the Atlantic Ocean and Mediterranean Sea. Feeding patterns were investigated in BLT and FRI individuals caught in the Gulf of Cadiz (East Atlantic) in 2019-2021 with the aim to decipher trophic interactions. Stomach content analyses showed a predominantly piscivorous diet, dominated by anchovy (Engraulis encrasicolus). Further cluster analysis coupled to a similarity profile permutation test revealed interspecific dietary differences in 2019 and 2021, as well as interannual differences in BLT. The trophic niche estimated from muscle and liver isotopic data was broader in BLT, and no considerable overlap of isotopic niches was found between the two species. Trophic positions (TP) were estimated in 2020 and 2021 using isotopic data of mesozooplankton as the food web baseline of the area. Muscle data showed that BLT occupied a higher TP than FRI in both 2020 and 2021, whereas liver data estimated a higher TP for FRI in 2020. Differences in isotopic compositions of BLT from the Gulf of Cadiz compared to individuals from the western Mediterranean suggest low mixing rates between populations.
PB Elsevier
SN 2352-4855
YR 2024
FD 2024-07
LK http://hdl.handle.net/10498/36394
UL http://hdl.handle.net/10498/36394
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 13-nov-2026