ACOUSTIC IDENTIFICATION OF ISADA KRILL, EUPHAUSIA-PACIFICA HANSEN, OFF THE SANRIKU COAST, NORTH-EASTERN JAPAN

In this study, the feasibility of identification and abundance estimat ion of isada krill, Euphausia pacifica, was examined using a two-frequ ency (38 and 120 kHz) method. The acoustic survey and midwater trawlin g were conducted off the Sanriku coast, northern part of Honshu, Japan . In one pattern, the SV difference between the two frequencies was la rge, and in the other, the SV difference was small. These results were interpreted by scattering models, and showed that discrimination betw een isada krill and walleye pollock was possible.