MEPS 297:225-231 (2005)  -  doi:10.3354/meps297225

Mitochondrial DNA panmixia in spiny lobster Palinurus gilchristi suggests a population expansion

K. A. Tolley1,*, J. C. Groeneveld2, K. Gopal1, C. A. Matthee1

1Evolutionary Genomics Group, Department of Botany and Zoology, Stellenbosch University,Private Bag X1 Matieland 7602, Stellenbosch, South Africa
2Marine and Coastal Management, Private Bag X2, Roggebay 8012, Cape Town, South Africa

ABSTRACT: The spiny lobster Palinurus gilchristi is endemic to the deep shelf waters along the southern coast of South Africa, where it supports a commercial fishery. Mark-recapture studies and phenotypic differences suggest there are 2 populations of this species along the coast, but it is unknown if the observed differences have arisen because of low gene flow and subsequent genetic differentiation. To investigate population structure and the physical processes that may have influenced gene flow, a portion of the mitochondrial DNA control region was sequenced for 187 lobsters across the entire range of the species. An analysis of molecular variance showed no significant genetic difference between the 2 putative populations. A mismatch distribution and Fu’s FS test indicated that this species has undergone a fairly recent demographic expansion (population size and geographic range). The genetic structure of this species could be panmictic due to a high amount of gene flow between the 2 regions during the larval stage, when the larvae are carried downstream by the Agulhas Current. Furthermore, the lack of genetic differences between the 2 putative populations could be the result of a recent demographic expansion accompanied by low diversity of haplotypes produced by a leading edge effect from the expansion.

KEY WORDS: Palinurus gilchristi · Decapoda · Lobster · Demographic expansion · Agulhas Current

Full text in pdf format