RT journal article
T1 Body size and isotopic profiles enable discrimination between long-term resident and highly migrant contingents of Atlantic bluefin tuna
A1 Medina Guerrero, Antonio
A1 Magro López, Ana
A1 Abascal, Francisco J.
A1 Varela Fuentes, José Luis
A2 Biología
K1 C:N
K1 Migrants
K1 Residents
K1 Stable isotope analysis
K1 Strait of Gibraltar
K1 Thunnus thynnus
K1 δ13C
K1 δ15N
AB The Atlantic bluefin tuna (ABFT) population ranges throughout the Atlantic Ocean and Mediterranean Sea, and consists of multiple contingents that use diverse habitats and show different movement patterns over the life cycle. Based on body size, elemental and isotopic data of C and N in muscle and liver, we analysed eastern-stock ABFT by comparing mid-sized individuals caught by hook-and-line gears with larger individuals harvested from traps in the Strait of Gibraltar (SoG). Our results show that trophic-related chemical markers have potential for separating temporarily sympatric contingents throughout the ABFT population range, reflecting size-dependent spatial distribution and differential patterns of residency and migration. We present evidence of long-term residency of ABFT in the SoG that persists until the estimated age of ∼5 years (size of ∼140 cm in straight fork length). This age apparently marks a turning point in the life history, where there occurs an ontogenetic switch in the migratory behaviour and distributional pattern. This study contributes new insight into our knowledge about size structure and residency-movement patterns in eastern ABFT. It shows distinct size-dependent migratory and spatial dynamics. The present results encourage further investigation on poorly studied ABFT contingents for a better understanding of the population dynamics towards more comprehensive management plans.
PB Elsevier Ltd
SN 1879-0291
YR 2024
FD 2024
LK http://hdl.handle.net/10498/35565
UL http://hdl.handle.net/10498/35565
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 10-nov-2026