Crossing the line: migratory and homing behaviours of Atlantic bluefin tuna
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AuthorsRooker, J.R; Arrizabalaga, H. (Haritz); Fraile, I.; Dettman, D.L.; Abid, N.; Addis, S.; Deguara, F.S.; Karakulak, F.S. (F. Saadet); Kimoto, A.; Sakai, O.; Macías-López, A.D. (Ángel David); Neves Santos, M.
KeywordsStable isotopes · Nursery origin · Otolith chemistry · Stock structure · Population
Assessment and management of Atlantic bluefin tuna Thunnus thynnus populations is hindered by our lack of knowledge regarding trans-Atlantic movement and connectivity of east- ern and western populations. Here, we evaluated migratory and homing behaviors of bluefin tuna in several regions of the North Atlantic Ocean and Mediterranean Sea using chemical tags ( δ 13 C and δ 18 O) in otoliths. Significant emigration of bluefin tuna from their place of origin was inferred from otolith δ 13 C and δ 18 O, with both eastern and western bluefin tuna commonly ‘crossing the line’ (45° W management boundary) in the Central North Atlantic Ocean and mixing with the other population. Several western migrants were also detected in Moroccan traps off the coast of Africa, indicating that trans-Atlantic movement occurs for members of the western population; however, the degree of mixing declined with proximity to the eastern spawning area (Mediterran- ean Sea). The origin of bluefin ...