Fine-scale spatial and temporal genetic structure of Atlantic cod off the Atlantic coast of the USA

Marine Ecology Progress Series

Isaac Wirgin¹  Adrienne I. Kovach¹  David L. Berlinsky¹  Timothy S. Breton¹  Lorraine Maceda¹ 

关键词: Atlantic cod;    Microsatellite DNA;    Single nucleotide polymorphism;    Population genetic structure;    Stock identification;    Gadus morhua;   

DOI  :  10.3354/meps08612

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: Atlantic cod Gadus morhua in US waters are currently managed as 2 stocks: (1) a Gulf of Maine stock and (2) a Georges Bank and south stock. This designation is decades old and warrants re-evaluation in light of concerns that fisheries management units may not reflect biologically meaningful population units. In this study, we used 10 microsatellite loci, the PanI locus, and 5 single nucleotide polymorphism markers to characterize the population genetic structure of cod in US waters. We found significant differentiation among temporally and spatially divergent populations of cod (global F_ST = 0.0044), primarily stemming from 2 potentially non-neutral loci, and evidence for a population structure that strongly contradicts the current 2-stock management model. This genetic structure was stable over a 5 yr period. Our results indicate that cod in US waters are broadly structured into 3 groups: (1) a northern spring-spawning coastal complex in the Gulf of Maine (GOM), (2) a southern complex consisting of winter-spawning inshore GOM, offshore GOM and sites south of Cape Cod, Massachusetts, and (3) a Georges Bank population. The strongest differentiation occurs between populations in the northern and southern complex (mean F_ST = 0.0085), some of which spawn in the same bays in different seasons. By means of mixture analysis, young-of-the-year fish sampled on juvenile nurseries were assigned to the spawning complex of their origin. Our findings contribute to a growing body of knowledge that Atlantic cod and other marine fish populations are structured on a finer scale than previously thought and that this structure supports biocomplexity and locally adapted populations. As such, it may be warranted to re-evaluate current management units and tailor management plans toward this finer scale.

【 授权许可】

Unknown