Genetic connectivity between Atlantic bluefin tuna larvae spawned in the Gulf of Mexico and in the Mediterranean Sea

PeerJ

article

Carolina Johnstone¹  Montse Pérez²  Estrella Malca³  José María Quintanilla¹  Trika Gerard⁴  Diego Lozano-Peral⁵  Francisco Alemany⁶  John Lamkin⁴  Alberto García¹  Raúl Laiz-Carrión¹ 

[1] Centro Oceanográfico de Málaga, Instituto Español de Oceanografía;Centro Oceanográfico de Vigo, Instituto Español de Oceanografía;Cooperative Institute for Marine and Atmospheric Studies, University of Miami;Southeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration;Centro de Supercomputación y Bioinnovación, Servicios Centrales de Apoyo a la Investigación, Universidad de Málaga;International Commision for the Conservation of Atlantic Tunas

关键词: Eastern Gulf of Mexico;    Microsatellite loci;    North Western Mediterranean;    Population structure;    Thunnus thynnus;    Fisheries management;    Western Gulf of Mexico;    Larval fish;    Mitochondrial control region;    Fish spawning;   

DOI  :  10.7717/peerj.11568

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

The highly migratory Atlantic bluefin tuna (ABFT) is currently managed as two distinct stocks, in accordance with natal homing behavior and population structuring despite the absence of barriers to gene flow. Larval fish are valuable biological material for tuna molecular ecology. However, they have hardly been used to decipher the ABFT population structure, although providing the genetic signal from successful breeders. For the first time, cooperative field collection of tuna larvae during 2014 in the main spawning area for each stock, the Gulf of Mexico (GOM) and the Mediterranean Sea (MED), enabled us to assess the ABFT genetic structure in a precise temporal and spatial frame exclusively through larvae. Partitioning of genetic diversity at nuclear microsatellite loci and in the mitochondrial control region in larvae spawned contemporarily resulted in low significant fixation indices supporting connectivity between spawners in the main reproduction area for each population. No structuring was detected within the GOM after segregating nuclear diversity in larvae spawned in two hydrographically distinct regions, the eastern GOM (eGOM) and the western GOM (wGOM), with the larvae from eGOM being more similar to those collected in the MED than the larvae from wGOM. We performed clustering of genetically characterized ABFT larvae through Bayesian analysis and by Discriminant Analysis of Principal Components (DAPC) supporting the existence of favorable areas for mixing of ABFT spawners from Western and Eastern stocks, leading to gene flow and apparent connectivity between weakly structured populations. Our findings suggest that the eastern GOM is more prone for the mixing of breeders from the two ABFT populations. Conservation of this valuable resource exploited for centuries calls for intensification of tuna ichthyoplankton research and standardization of genetic tools for monitoring population dynamics.

【 授权许可】

CC BY