Spatial distribution and some features of biology of the two-line eelpout Bothrocara brunneum (Zoarcidae) in the Sea of Okhotsk

Abstract

According to data of integrated trawl surveys, specific features of distribution and some traits of biology of the two-line eelpout Bothrocara brunneum in the Sea of Okhotsk are shown. The species under investigation is spread over the entire sea, and the average density of its distribution averages 0.29 ind./km2 or 0.11 kg/km2. It is found at depths of 200–1995 m, mainly in the range of 300–900 m. Juveniles inhabit large depths, while large individuals are distributed over the entire slope. Optimal temperature of habitation is 1.5–2.3°C. The main center of reproduction is the slope of the northern part of the sea. In catches, individuals with a length of 6–71 (on average, 41) cm and a weight of 20–2600 (757) g occur. Sexual maturation takes place on reaching a length of 45–50 cm; at the same time, gravimetric increments begin to be ahead of linear ones. Sex ratio is 1 : 1. Sexual dimorphism with respect to sizes was not revealed. Spawning is extended: individuals with mature gonads are found in the summer-autumn period. In net catches, fish aged 4–8 years dominate, while fish aged 2–7 years dominate in trawl catches.