Mitochondrial DNA variation in Northeast Atlantic and Mediterranean populations of Norway lobster, Nephrops norvegicus

Abstract

Analysis of the genetic structure of the Norway lobster (Nephrops norvegicus), a marine crustacean with high commercial value, was undertaken to gain information regarding the differentiation of Atlantic from Mediterranean populations of marine invertebrates. Restriction fragment length polymorphism analysis of two mitochondrial DNA segments, 3.6 kilobases in total, was performed. Twelve populations from the North Sea, Irish Sea, Portuguese coast and Aegean Sea were analysed. Low levels of differentiation were found among them (F(ST) = 0.018, P < 0.001) and there were no signs of an Atlantic-Mediterranean divide or of an isolation-by-distance scheme of differentiation. Possible reasons for these low levels of differentiation can be found in the recent expansion of N. norvegicus populations. This is supported by the mismatch distribution of pairwise haplotype differences, as well as by the high mean haplotype diversity (h = 0.93) combined with medium nucleotide diversity (pi = 0.0057) (in comparison to values for marine crustaceans or teleosts) found in this study. This combination of high levels of haplotype diversity with moderate to low levels of nucleotide diversity has also been frequently attributed to a recent time of divergence for various marine species. No evidence was found for a Mediterranean refugium during glaciation periods, separate from the Atlantic, as has been reported for some marine species. The Irish Sea population was the most differentiated as a result of reduced levels of diversity. Results are also discussed in the light of future management of N. norvegicus stocks.

Historical population dynamics and demography of the eastern Atlantic pomacentrid Chromis limbata (Valenciennes, 1833)

“…Recently, studies have focused on the relationship between the eastern Atlantic and Mediterranean (Alvarado Bremer et al, 2005;Bargelloni et al, 2003Bargelloni et al, , 2005Costagliola et al, 2004;Domingues et al, 2005;Lemaire et al, 2005;Naciri et al, 1999;Stamatis et al, 2004;Zardoya et al, 2004). In contrast, little is known about genetic relationships between populations of the Macaronesian islands (Azores, Madeira, Canaries, and Cape Verde; Almada et al, 2005;Guillemaud et al, 2000).…”

Genetic structure of the high dispersal Atlanto-Mediterreanean sea star Astropecten aranciacus revealed by mitochondrial DNA sequences and microsatellite loci

“…Many studies have used indirect genetic tools such as mitochondrial DNA (mtDNA), nuclear DNA or a combination of the two to analyze genetic structure in high dispersal Atlanto-Mediterranean invertebrates (e.g., Féral et al 1995;Zane et al 2000;Launey et al 2002;Diaz-Almela et al 2004;Duran et al 2004a;Roman and Palumbi 2004;Stamatis et al 2004;Triantafyllidis et al 2005;Peijnenburg et al 2006;Calderon et al 2008). Differing conclusions regarding the influence of the Atlantic-Mediterranean division on population structuring were drawn in these studies depending not only on the species investigated but also on the genetic markers used and the sampling pattern.…”

“…The role of the Atlantic-Mediterranean division as a potential barrier to gene flow has increasingly been investigated for various planktotrophic invertebrate species (e.g., Borsa et al 1997;Launey et al 2002;DiazAlmela et al 2004;Duran et al 2004a;Stamatis et al 2004Stamatis et al , 2006Saavedra and Pena 2005;Calderon et al 2008). While the Strait of Gibraltar geographically divides the two basins, the Almería-Oran front is thought to be a genetic separation area.…”

“…Patarnello et al (2007) discovered that even between closely related taxa with comparable biologies the Atlanto-Mediterranean transition does not always induce a congruent population genetic structure, which could be due to the differences in demographic history between these species. Restriction fragment length polymorphism (RFLP) of mtDNA in the Norway lobster Nephrops norvegicus, for example, showed no genetic differentiation between the Atlantic and the Mediterranean (Stamatis et al 2004). However, pronounced differentiation between Atlantic and Mediterranean populations was detected in the closely related European lobster Homarus gammarus (Triantafyllidis et al 2005) using also RFLP of mtDNA.…”

Genetic variation in the lesser flying squid Todaropsis eblanae (Cephalopoda, Ommastrephidae) in east Atlantic and Mediterranean waters

“…This is likely the case in a number of species of both fish and cephalopods (Lundy et al 1999, Naciri et al 1999, Bahri-Sfar et al 2000, Dillane 2001. Conversely, there is evidence to suggest that movement between the Mediterranean and Atlantic occurs in some species of finfish and shellfish, such as swordfish (Kotoulas et al 1995), the European anchovy (Magoulas et al 1996) and lobsters (Stamatis et al 2004). Further sampling of Todaropsis eblanae within its range in the Mediterranean would provide a better assessment of population structure and help to calibrate observed differences between the Mediterranean and Atlantic waters.…”