Some Characteristics of the Pelagic Redfish (Sebastes Mentella Travin) from Weather Station Alfax

Abstract

The existence of a permanent pelagic population of the redfish Sebastes mentella Travin in the Irminger Sea has been confirmed as a result of successful angling trials carried out by ships occupying Weather Station Alfa (62°N, 33°W) during the years 1962 to 1965. No specimens of S. marinus or ‘intermediate’ forms were found amongst the 207 specimens returned to the laboratory. The sample was predominantly female (7:1) although males were found in equal or greater numbers in the period late December to March. All females were sexually mature and all males were approaching or had reached full sexual maturity. Captures were made at depths ranging from 50 to 350 m but chiefly between 100 and 150 m in the summer. Fishing was most successful during the periods May to August and December to March. There was considerable but continuous variation in body proportions and age/length relationships. Much less variation occurred in the numbers of vertebrae and of pyloric caeca. Allowing one pair of growth rings to one year's growth, it is thought that the ages ranged from approximately 15 to 57 years, with a mean age of 31 years and it is believed that sexual maturity in females occurs between 15 and 25 years of age. Fecundity, which varies according to size (length), ranges from approximately 20,000 to 150,000. No evidence was obtained to show the relationship of this population to any other redfish population nor is there any clear evidence to demonstrate migration or movement. The seasonal variation in the number of males caught at Station Alfa may possibly be due to either horizontal or vertical migration.