MEPS 187:171-178 (1999)  -  doi:10.3354/meps187171

Microsatellite analysis of genetic diversity in the squid Illex argentinus during a period of intensive fishing

Greg J. Adcock1,*, Paul W. Shaw1, Paul G. Rodhouse2, Gary R. Carvalho1

1Molecular Ecology and Fisheries Genetics Laboratory, Department of Biological Sciences, University of Hull, Hull HU6 7RX, United Kingdom
2British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Rd, Cambridge CB3 OET, United Kingdom

ABSTRACT: Levels of genetic diversity and population differentiation were examined in temporally (1990 to 1997) and geographically separated samples of the argentine short-finned squid Illex argentinus using 7 microsatellite loci. Number of alleles (mean number of alleles per locus over all samples = 24.1) and heterozygosity (mean observed heterozygosity per sample = 0.84) were high for all samples, indicating that these loci have a greater potential utility for investigating population genetic structure than allozyme markers used in previous studies. Genetic diversity did not differ significantly between samples taken 5 yr after commencement of the fishery (1990) and those collected during a period of progressively intense fishing pressure (1994 and 1997). Several small but significant differences in between-sample genetic variation (FST) were observed, but these could not confirm the previous suggestion of cryptic species or several well-defined stocks within the fished population.

KEY WORDS: Microsatellite · Genetic diversity · Illex argentinus · Squid · Population genetics · Fishing

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