Reanalysis of long-term surveys on the ecology and biology of mud skate (Rhinoraja taranetzi Dolganov, 1985) in the northwestern Pacific (1993–2002)

摘要: Summary Based on data sampled in 1992–2002, the occurrence, spatial distribution, bathymetry, bottom temperatures preferences, size composition, feeding, and some features of reproductive biology mud skate Rhinoraja taranetzi Pacific waters off northern Kuril Islands southeastern Kamchatka are considered. Throughout year, was most abundant central part study area, from coast Onekotan Island to southern tip peninsula. The proportion this species trawl catches different seasons has changed slightly. However, maximum catch occurred September–December. In April–May skates occupied shallower depths (mean 230–270 m), moving deeper summer period 340–390 m). December–March at lower 0.8–1.6°C) whereas rest year it inhabited warmer with mean 2.5–3.1°C. decreasing body weight depth observed, indicating that adult juvenile inhabit depths. Total length ranged 17 70 cm a 51.71 cm. Relation between total (TL, cm) (W, g) was: W = 0.0029TL3.1614 (r2 = 0.978). Males were more among small ( 30 cm) comprising about 70% 60–70 cm class. Female longer heavier than males 56.9 vs 51.2 cm 1206 807 g, respectively). This is considered be benthophagous, consuming mostly amphipods (34.9% by weight), polychaete worms (27.6%), decapod crustaceans (12.7%), fishery discards (13.9%). Small (20–40 cm) fed (85.4%); medium-sized (40–60 cm) ate (40.2%), polychaetes (29.1%) decapods (19.3%); largest individuals (>60 cm) consumed offal (27.9%) less (26.6%) (27.7%). Preliminary maturation western Bering Sea showed females become mature lengths above 61 cm TL.