Studies of the genetic relationship between deep-sea and oceanic Sebastes mentella in the Irminger Sea

Abstract

A joint venture between Iceland and Norway to study the beaked redfish, Sebastes mentella, in the Irminger Sea was undertaken in 1995. The genetic relationship of deep-sea and oceanic S. mentella in the Irminger Sea and their relationship to redfish groups in adjacent waters were studied by gel electrophoresis and isoelectric focusing of haemoglobin and allozymes. The oceanic type of redfish in the Irminger Sea occurred as a homogenous group, but differed from the deep-sea type. This result was mainly based on frequency distributions of the enzyme loci MEP-1* and IDHP-2* and minor haemoglobin components. Heterogeneity was found within the deep-sea type, which also showed similarities with beaked redfish from the Icelandic shelf area. One sample of “untyped” S. mentella found below 600 m resembled the oceanic type in morphology and gene frequencies. Both types of S. mentella differed from S. mentella from Canada and Norway, but they could not be distinguished from immature S. mentella from Greenland as far as could be judged from previous studies.