New data on Pacific flatnose, Antimora microlepis (Moridea) from the Northwestern Pacific Ocean

摘要

Data on endemic for the North Pacific Ocean morid fish Pacific flatnose, Antimora microlepis, was sampled during 1993-2000 within the Pacific waters off the northern Kuril Islands and southeastern Kamchatka. Patterns of their spatial and vertical distribution, size composition, age, growth rate and some other biological features are considered. Totally 1204 trawl catches contained Pacific flatuose were analyzed, 844 specimens were measured; 109 otholits were examined. Pacific flatuose were found within the whole area studied along the continental slope in depth range of 250-1800 m. Spatial distribution was relatively even, the catches varied from occasional to several hundreds specimens per hour trawling, the areas with large catches were not occurred. Maximum catches over 25 specimens per hour trawling were noted on the depth about 850 m. Other large catches, reaching 20 specimens per hour trawling, were occurred on the depths of 250, 400-500, and 1400 m. Maximum catches about 20 specimens per hour trawling were occurred in bottom temperature ranges 1.1-1.5, 2.1-3.0 and over 4.5°C. Pacific flatnose in the catches were represented by fishes, having total length 14 to 63 cm with mean 26.23 ± 0.19 cm. Fishes with length 21 to 30 cm were most abundant, constituting 81.2 % of catches. Only immature specimens represented our catches, and fish weight rose with depth increasing. Males were somewhat longer and heavier than females. Thus, mean length and weight of males were 35.2 cm and 327.9 g respectively, while that of females were 33.4 cm sad 289.2 g. The share of females in the catches varied from 34.5 % among size class 46-50 cm to 57.1 % among fishes over 55 cm. Average share of females was 47.8 %. The age of fishes found in the catches was determined 2 to 20 years. The mean length of specimens aged 2 years was 20.0 cm, 3 -21.1, 4 - 24.2, 5 - 25.1,6 - 28.3, 7 - 31.6,8 - 37.7, 9 - 39.4, 10 -40.3cm. Only single specimen with length 63cm was aged 20 years. Relationships between otolith dimensions (length, width, and weight) and age were found.