Small and Abundant but Understudied Ribbed Sculpin Triglops pingelii (Cottidae, Teleostei) from the Kara Sea (Siberian Arctic): Distribution, Biology, and Comparison with Congeners

Abstract

The features of the spatial and vertical distributions, and size–age and size–sex structures of the ribbed sculpin Triglops pingelii of the Kara Sea are presented. In September 2019, this species was recorded at depths from 18 to 235 m at a bottom temperature from −1.5 to +1.6 °C. The densest concentrations were recorded northeastward of the Yamal Peninsula, at the outlet of the Gulf of Ob at a depth of 18–21 m and a bottom temperature from −1.5 to −1.0 °C. Individuals with a length of 46–126 mm and a body weight of 0.35–15.60 g aged 1+ to 4+ years were recorded in trawl catches. However, fish with a length of 51–90 mm and a body weight < 6 g aged 1+–2+ years dominated. Among fish > 71 mm long, the proportion of females increased sharply, reaching 100% with a length of 120 mm. The individual fecundity of female ribbed sculpins in the Kara Sea with a length of 89–123 mm varied from 100 to 316 (on average 215 ± 15) eggs. It is shown that this species is a necto-bentho-ichthyophage whose main prey are benthic and bentho-pelagic crustaceans (mainly amphipods and mysids), as well as juveniles of various fish, the total proportion of which is >99% of the food weight. In this sculpin, age-related changes in the diet composition are well expressed, i.e., as the size increases, the relative importance of the former prey group decreases sharply, and that of the latter two groups, on the contrary, increases. A comparative analysis of data on the biology and distribution of the six most abundant or common Triglops spp. makes it possible to attribute the ribbed sculpin to medium-sized representatives of the genus, whose maximum length is similar to those of T. jordani from the North Pacific, as well as T. murrayi and T. nibelyni from the Arctic. The lifespan of the ribbed sculpin is within the same limits as reported for other Triglops spp. Its individual fecundity in the Arctic seas is comparable to that of other Triglops species living here, but is significantly lower than that of individuals of this species and other congeners from the northwest Pacific Ocean.