The food habits, age, and growth of three midwater fishes (Stenobrachius leucopsarus, Stenobrachius nannochir, and Leuroglossus schmidti) from the Southeastern Bering Sea

Abstract

The food habits, age, and growth of two lanternfishes (Stenobrachius leucopsarus and Stenobrachius nannochir nannochir) and the northern smoothtongue (Leuroglossus schmidti) from the southeastern Bering Sea are examined in order to assess the trophic importance of these organisms at the northernmost limit of their distribution. All three species prey exclusively upon zooplankton. The order of predominant dietary components is: copepods, euphausiids, ostracods, and amphipods (S. leucopsarus); copepods and ostracods (S. n. nannochir); and larvaceans, copepods, and ostracods (L. schmidti). Seasonal and diurnal-nocturnal dietary variations are noted for Stenobrachius leucopsarus. Maximum growth of each species occurs during the first year and is followed by decreased but very uniform growth in the remaining years of life. Sexual maturity is attained at age four by both lanternfish and at age three by Leuroglossus schmidti. The greatest longevity of S. leucopsarus and L. schmidti is six years; S. n. nannochir may only reach age five.