Fishes incidentally caught by Japanese Antarctic krill commercial fishery to the north of the South Shetland Islands in February 1997

Scientific observations on fishes incidentally caught during krill fisheries by F/V Niitaka Maru were made from 1 to 23 February, 1997 to the north of the South Shetland Islands. Among 80 hauls examined, a total of 61 specimens belonging to 4 families and 7 species, Electrona antarctica (50 specimens), Electrona carlsbergi (4), Protomyctophum tenisoni (1), Gymnoscopelus opisthopterus (1), Notolepis coatsi (3), Benthalbella elongata (1) and Neopagetopsis ionah (1), were captured as by-catch in 16 hauls. Except for one channichthyid juvenile of Neopagetopsis ionah, by-catch fishes were referred to the bathypelagic families, the Myctophidae, Paralepididae and Scopelarchidae. Among by-catch fishes, Electrona antarctica of the Myctophidae was the most abundant. This species was found in 12 hauls, and its estimated value was 20 to 380 ind./t. The present by-catch data did not provide clear relationship between the abundance of by-catch fish and the krill CPUE. This observation is different from by-catch data made in previous studies. In the present survey, the abundance of by-catch was well correlated to the time zone of trawling, which is thought to depend on a large amount of bathypelagic fishes in the catches.