Heterozygosity and Morphological Variability in the Orange Roughy,Hoplostethus atlanticus(Teleostei: Trachichthyidae)

Abstract

Eleven polymorphic loci were screened in six southern Australian populations of the deepwater teleost Hoplostethus atlanticus, the orange roughy. Associations between heterozygosity and morphological variability were examined. No significant correlations between heterozygosity at individual loci and length were observed. Homozygotes at ADA* had significantly greater length variance than heterozygotes in one population whereas in another population, homozygotes for PGM-2* had significantly reduced length variance compared with heterozygotes. No other single locus/length variance comparisons were significant. One of the six populations showed a significant positive regression of individual length on multilocus heterozygosity; regressions in the other five populations were nonsignificant and variable in slope direction. No significant correlations were detected between multilocus heterozygosity category and mean length or coefficient of variance of length. Three of the populations were also examined for variation in four meristic characters and one measure of bilateral asymmetry: no consistent associations were detected between individual or multilocus heterozygosity and mean or variance of these characters. The data provide little evidence for significant relationships between individual or multilocus heterozygosity and morphological variability in orange roughy.