The first data on the diet and reproduction of Fedorov's lumpsucker (Eumicrotremus fedorovi)

Ilya Gordeev, Kristina Zhukova, and Svetlana Frenkel
Cover date
Published online 8 April 2021

A total of 69 specimens of Fedorov’s lumpsucker (Eumicrotremus fedorovi) caught on the continental shelf and slope of Simushir Island in the northwest Pacific Ocean were dissected and studied for stomach contents. The Fedorov’s lumpsucker was found to feed mainly on the young of fish species, including the walleye pollock (Gadus chalcogrammus), northern lampfish (Stenobrachius leucopsarus), and northern smoothtongue (Leuroglossus schmidti), crustaceans, such as Themisto pacifica, Primno macropa, calanoids, gammarids, mysids, and caprellids, and squid. Histological analyses of ovaries revealed iteroparity, determinate fecundity, group-synchronous ovarian development, and total spawning. Testes were of an unrestricted lobular type. Chorion and thick zona radiata of Fedorov’s lumpsucker correspond to the condition of eggs in specimens of other fish species that release demersal eggs. Absolute fecundity values of Fedorov’s lumpsucker in our study were significantly less than those that have been reported for other species of Cyclopteridae. The results of this study provide the first data on this little known species of this family.