Distribution and Some Traits of Biology of Sculpins of Genus Triglops (Cottidae) in the Sea of Japan

Abstract

It was revealed that the southern border of the range of spectacled sculpin Triglops scepticus runs in the region of 37°23′ N. It has been confirmed that the southern border of the range of Jordan’s sculpin T. jordani is located in the South Korean waters; of ribbed sculpin T. pingelii range, in the North Korean waters. In the Russian waters of the Sea of ​​Japan, Jordan’s sculpin occurs at depths of 14–230 m and water temperature of –1–13.8°C; ribbed sculpin, 30–424 m and –0.3–9.7°C; spectacled sculpin, 57–586 m and 0.3–4.3°C, respectively. In the warm period, the concentrations are somewhat shifted towards shallow waters; in the cold period, towards deep waters. The body length and weight of one-sized individuals increase with the degree of deep-water preference. The body length of Jordan’s sculpin reaches 20 cm; of ribbed sculpin, 23 cm; of spectacled sculpin, 26 cm. In all three species, females are larger than males. Females dominate populations of Jordan’s and ribbed sculpins while in spectacled sculpin the share of males is higher. In the northwestern part of the Sea of Japan spectacled and ribbed sculpins are planktivores consuming mainly hyperiids and euphasiids while Jordan’s sculpin is nectobenthivore with food dominated by mysids and small shrimps. During the spring—summer period mean values of daily rations of adult specimens of Jordan’s, ribbed and spectacled sculpins are 3.3, 2.4 and 1.8% of body weight, respectively. The biomass of g. Triglops species in the Russian zone of the Sea of Japan is about 2100 tonnes.