Publication Abstract

Genetic population structure across a range of geographic scales in the commercially exploited marine gastropod Buccinum undatum

Natural and anthropogenic determinants of genetic population structure and diversity in a commercially exploited marine gastropod, Buccinum undatum

D. Weetman, L. Hauser, P.W. Shaw, M.K. Bayes and J.R. Ellis

Marine invertebrates are increasingly exploited as food resources worldwide but detailed studies of their population structure remain scarce. Using microsatellites we investigated the genetic structure of the direct-developing, subtidal neogastropod, Buccinum undatum, at various spatial scales. Cluster analysis identified five groupings of populations, the minor four of which appear to have diverged from the major populations on the European continental shelf because of either large geographical separation (Nova Scotia and Reykjavik) or via population bottlenecks (Solent, UK and Skaggerak). Within the Shelf grouping most pair-wise tests of differentiation were significant, but the average F_ST was only 0.021, despite an average pair-wise distance of 900 km. Estuarine populations showed both lower genetic diversity and greater differentiation than their nearest (more offshore) neighbours, and there was a consistent pattern of asymmetric, seaward-biased migration. Isolation by distance was generally absent but was detected among North Sea coast populations, which, unlike the estuarine locations, appear close to equilibrium. Patterns of migration in the Solent point towards a very recent bottleneck and ongoing process of recolonisation. The timescale and several other lines of evidence suggest an anthropogenic cause of the decline, with TBT-induced imposex a likely candidate. Whilst our results are generally consistent with widespread semi-continuity of whelk populations of quite large effective size, certain types of habitat harbour populations that seem isolated by ecological factors, and will be particularly prone to over-exploitation. Our data also add to growing evidence that life-history characteristics are poor quantitative predictors of levels of genetic differentiation in marine invertebrates.

Reference:

D. Weetman, L. Hauser, M.K. Bayes, J.R. Ellis and P.W. Shaw (2006) Genetic population structure across a range of geographic scales in the commercially exploited marine gastropod Buccinum undatum. Marine Ecology Progress Series, 317: 157-169

D. Weetman, L. Hauser, M.K. Bayes, J.R. Ellis* and P.W. Shaw

Marine Ecology Progress Series, 317: 157-169