Studies of Pacific cod during longline fishing in the Bering Sea in October 2024

Abstract

The purpose of the work: to monitor aquatic bioresources, obtain biostatic data, determine the age composition of catches, determine the parasitic infestation of fish and hematological parameters.

Methods used: During longline fishing, fishing information was collected, ichthyological and ichthyopathological work (hematological and partial helminthological analysis of fish) was carried out using generally accepted methods.

Novelty: commercial, biological, and ichthyopathological data were obtained on the state of the commercial population of Pacific cod in the western Bering Sea in the autumn of 2024.

Results: Average daily catches varied from 1161 kg to 10255 kg (average 3998 kg). The size of cod catches in one order varied from 99 kg to 4600 kg (average 822 kg). The size composition of Pacific cod in the West Bering Sea zone was within 39-102 cm (average 54.3 cm). The share of non-commercial size fish (less than 40 cm) was 0.6%. The age range is represented by individuals from 2 to 7 years. The modal group consisted of individuals 3 and 4 years old with a length of 40 to 70 cm. As a result of parasitological research, a low degree of invasion of the muscles and liver of cod by larvae of nematodes Anisakis sp. and Pseudoterranova decipiens was established. Hematological parameters were determined; in isolated cases, erythrocyte pathologies were noted (less than 1%).

Practical significance: the results of the work can be used in the development and adjustment of materials for forecasting the total allowable and recommended catch and recommendations for effective fishing.