BIOLOGICAL CHARACTERISTICS AND FOOD COMPOSITION OF THE SHRIMP, SABINEA SEPTEMCARINATA (SABINE 1824) (CRUSTACEA, CRANGONIDAE) FROM THE SHELF OF THE KARA AND LAPTEV SEAS

The size and sex structure, the dependence of the state of the gonads of females on the size of the individual, and the composition of the food of the shrimp, Sabinea septemcarinata (Sabine 1824) (Crustacea, Crangonidae) from the Laptev Sea, the Khatanga Bay and the Kara Sea are described (598 individuals: 230 of them had empty stomachs, 368 contained food in their stomachs, and 34 had them full). The shrimps were collected in August–September 2016. The total body length of the shrimps examined varied from 31 to 103 mm: 32–103 mm in females and 31–74 mm in males. The lifespan seems to last 3–4 years in females, vs 2–3 years in males. Based on the condition of the gonads of the females, the time of material collection coincided with spawning. Among the females there are individuals at all stages of the reproductive cycle: feeding, spawning and preparing for the next spawning. This indicates extended population spawning. Sabinea septemcarinata belongs to the life form of burrowing shrimp. According to the frequency of occurrence in the stomachs, detritus takes the first place (92.2%). The second and third places are taken up by cumin crayfish and sedentary polychaetes, which occur in almost every second and third stomach (frequency of occurrence 37.7 and 23.9%, respectively). Sand shows a frequency of occurrence of 50.3%. In the virtual food lump, a little more than a third of its volume is taken up by detritus (39.7%), followed by cumin crayfish and polychaetes that take second and third places (23.6 and 22.6%, respectively). Consequently, S. septemcarinata feed on infauna. Thus, S. septemcarinata are characterized by elements of an attacking predator and a detritophage.