The Biological Features of the Atlantic Cod Gadus morhua L., 1758 (Gadiformes: Gadidae) of the Murmansk Coast: Race Composition and Fishing

Abstract

The biological features of Atlantic cod in the coastal zones of the Murman for 1999–2006 were studied. The age composition, growth rate and maturation, feeding habits, and structure of otoliths were analyzed. Histological and genetic studies were carried out. It has been shown that young cod mainly lives and spawns in Western Murman bays. Older cod leaves the bays due to insufficient food supply. The growth rate of young coastal cod is comparable to that of cod in the open part of the Barents Sea. With age, the cod of the open sea areas noticeably overtakes the cod that lives in the coastal zone in growth. It was noted that the cod spawns in the bays with both coastal and Atlantic types of otoliths. Studies of genetic polymorphisms indicate a high degree of genetic similarity between cod groups in the Norwegian and Barents Seas under the influence of currents (branches of the Norwegian Atlantic Current, the Murmansk Coastal Current) and against the background of migrations at different stages of ontogeny of cod from coastal and open water areas.