0-group cod (Gadus morhua) in captivity: Differential survival of certain genotypes

Abstract

Genotypes at LDH-3 (lactate dehydrogenase) and PGI-1 (phosphoglucoisomerase) in 263 0-group specimens of Atlantic cod (Gadus morhua) caught in Trondheimsfjorden, Norway, in fall 1983 showed significantly different survival rates during 72 days in captivity. The heterozygote was nominally superior at both loci, and there was a significant accumulation of double heterozygotes among the survivors. Apparently, LDH-3 and PGI-1 are not selectively neutral, and allele frequency differences at these two loci between groups of cod in nature should not be interpreted as markers of reproductive isolation. The results are related to current concepts of cod population structure. © 1985 Biologische Anstalt Helgoland.