Worldwide genetic structure of albacore Thunnus alalunga revealed by microsatellite DNA markers

Abstract

One of the most common problems in fisheries is the definition of management units. Albacore Thunnus alalunga is an important species for commercial fisheries. Its population structure is still partially unknown; however, on the basis of fisheries data, tagging experiments, and morpho-ecological studies, 6 management units are currently accepted for this species. The main objective of this study was to define genetic entities within T. alalunga and to discuss the appropriateness of current management units. For this purpose, 13 microsatellite loci were applied to 551 albacore samples collected worldwide, and the population genetic structure was assessed. The most relevant differences between management and genetic units were that (1) Atlantic and Indian Ocean samples are genetically indistinguishable, and (2) possible differentiation exists within the Pacific Ocean and also within the Mediterranean Sea. Thus, this study provides genetic information to clarify albacore population delimitation, which is a key factor to reach the demanded sustainable management of this resource.