Growth, production and reproduction of the myctophid fish Benthosema glaciale from western Norway and adjacent seas

Abstract

Age, growth, mortality, production and reproduction were studied on material of Benthosema glaciale from some fjords of western Norway and from the adjacent ocean. Samples were collected using pelagic trawls and Icaacs-Kidd midwater trawls. Age was studied by means of otoliths although the seasonal cycle of zone formation was variable. Growth was highly variable within the material, L∞ of the von Bertalanffy's growth equation ranging from 70 to 87 mm and K from 0.19 to 0.46. The instantaneous natural mortality was about 0.7. The maximum sustainable yield per recruit can be obtained with a first age of capture of about 2 years and a fishing mortality of 1.5 or higher. B. glaciale reaches maturity at an age of 2 or 3 years and spawn mainly during summer. The development of the ovaries is briefly described. Its mean fecundity is 700 eggs/female.