Allozyme variation between populations of baitfish species Stolephorus heterolobus and St. devisi (Pisces : Engraulidae) and Spratelloides gracilis (Pisces : Dussumieriidae) from Papua New Guinea waters

Abstract

Allozyme variation of two species of anchovies, St. heterolobus and St. devisi, and one presumptive species of sprat, Sp. Gracilis, was examined. Three populations of the two anchovies showed marked differences in the allele frequencies of two polymorphic enzyme loci: adenosine deaminase (Ada) and malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+) (Mod) in St. heterolobus and adenosine deaminase and guanine deaminase (Gda) in St. devisi. It is proposed that populations of these anchovies are semi-isolated. The two colour morphs of Sp. Gracilis were observed in both populations studied. They appear to be fixed for alternate alleles in at least five enzyme loci and so are probably two separate species.