Original Articles

GENETIC VARIATION IN TWO POPULATIONS OF THE ORANGE ROUGHY (HOPLOSTETHUS ATLANTIC US) FROM NAMIBIA

DOI: 10.1080/10183469.1998.9631413
Author(s): N.S. FlintDepartment of Zoology, South Africa, F.H. van der BankDepartment of Zoology, South Africa, P.J. TheronDepartment of Zoology, South Africa, A. Staby, Namibia

Abstract

The orange roughy (Hoplostethus atlanticus) is a relatively new commercially exploited fish species, but it is currently ranked third amongst the world's top five seafood products. Gene products of 22 protein coding loci in two populations off the coast of Namibia were studied by horizontal starch gel electrophoresis. Values of 31.8% and 40.9% (0.95 criterion), and 0.137 (± 0.0.47) to 0.143 (± 0.042) were obtained for the percentage of polymorphic loci and the average heterozygosity of the two populations respectively. The unbiased genetic distance was 0.004 between the populations and the average fixation index (FST) value was 0.019. These values are comparable with results obtained in a similar study of orange roughy near New Zealand, where the percentage of polymorphic loci ranged from 22.7% to 38.1% (0.95 criterion) and heterozygosity values ranged from 0.104 (±0.037) to 0.125 (±O.044). The genetic differentiation observed between the populations suggests that it would be inadvisable to use a global total allowable catch quota for orange roughy off the Namibian coastline and we recommend that each of the populations be managed individually.

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