Changes in Greenland Halibut Growth, Condition and Fecundity in the Northwest Atlantic (Flemish Pass, Flemish Cap and Southern Grand Bank)

Abstract

The Greenland halibut fishable stock has been declining substantially since late-1980s, according to both surveys and commercial fishery indices, particularly among the ages 10+, which corresponds to the females age at 50% maturity. In this paper it is reviewed the effect of this apparent reduction in the stock abundance in two main groups of biological parameters, namely growth and reproductive parameters, since late-1980s. Among growth parameters, the analysis of the first year growth is undertaken both by cohort and by geographic areas, assuming that density dependence might be the most severe at younger age classes. This is made using records of the respective first annual ring otolith diameters. Other growth related index such as the condition factor is also analysed. About the reproductive parameters, two aspects, are considered: the interannual variations in length-at-maturity and in the potential fecundity. A common feature observed is the relative stability of those characteristic through the period analysed, which could support a certain resiliency of the life history traits in this species.