Genetic variation of the spiny spider crab Maja brachydactyla in the northeastern Atlantic

Abstract

The spiny spider crab Maja brachydactyla is a decapod crustacean that inhabits the northeastern Atlantic, from the British Isles to Senegal, and is the target of intense fishing activity. In the absence of previous genetic studies, we describe the genetic variability and structure of this species along Atlantic European coasts, paying special attention to the northwestern Iberian Peninsula (Galicia), where this species may be overexploited. Analysis of 2 mitochondrial fragments and 9 microsatellites indicates that these populations maintain appreciable levels of genetic diversity, most of which are found within localities. This scenario could be explained by quite large effective population sizes and noticeable levels of gene flow. M. brachydactyla in the northeastern Atlantic do not show any signs of a genetic bottleneck, and effectively conform to a diverse metapopulation with limited structure.

Genetic structure of Carcinus maenas within its native range: larval dispersal and oceanographic variability

“…Expected heterozygosity values were 0.696 (SWD), 0.686 (MEN-IP) and 0.663 (MOR), which are similar to values reported for microsatellites for other decapod crustaceans (e.g. H e = 0.5 to 0.6 for Pachygrapsus marmoratus [Silva et al 2009]; H e = 0.7 to 0.8 for Maja brachydactyla [Sotelo et al 2008]). The GENELAND model identified the Moroccan sample as an individual cluster, despite the failure of the F ST approach to distinguish clearly Morocco from MEN-IP samples in individual comparisons.…”

“…Other marine crabs with high larval dispersal capacity show similar patterns of low genetic differentiation over extensive spatial scales (McMillen-Jackson & Bert 2004, Pfeiler et al 2005, Cassone & Boulding 2006, Ungfors et al 2009). Furthermore, weak or a complete lack of genetic differentiation along the European Atlantic coast has also been documented for other invertebrate species with high dispersal potential, such as the sea urchin Paracentrotus lividus (Duran et al 2004), the European lobster Homarus gammarus (Triantafyllidis et al 2005), the netted dog whelk Nassarius reticulatus (Couceiro et al 2007), the spiny spider crab Maja brachydactyla (Sotelo et al 2008) and the velvet swimming crab Necora puber (Sotelo et al 2009). Although it is apparent therefore that taxa exhibiting similar life-history parameters and high potential vagility may often show apparent panmixia along the Atlantic coast, exceptions continue to emerge (e.g.…”

Annotated checklist of brachyuran crabs (Crustacea: Decapoda) of the Iberian Peninsula (SW Europe)

“…Balss, 1922 This species was established by the recognition of two distinct taxa within M. squinado sensu lato: M. squinado sensu stricto in Mediterranean waters and M. brachydactyla in Atlantic waters. The first hints given by Neumann (1998) were recently confirmed by DNA analyses (Sotelo et al 2008). It should be pointed out that M. brachydactyla is also known to occur in the western Alboran Sea (Abelló et al 2014).…”

Molecular Markers, Natural History, and Conservation of Marine Animals

“…Ultimately, the N e estimate is determined by comparing the observed data to the simulated data for a series of statistics relating genetic variation to N e , including expected heterozygosity, number of alleles per locus, mean and variance of multilocus homozygosity, and others. Although the idea of calculating N e from observed within-population genetic variation (or temporal change in allele frequencies) is attractive, empirical results can be erratic; a recent study employed two different methods for estimating N e in the spiny spider crab and obtained values that varied from 100 to 1 million for the same population (Sotelo et al 2008). Palstra and Ruzzante (2008) have discussed some of the important complications in estimating N e , including importance of both proper sampling and consideration of population demographic factors.…”