Seasonal change in distribution of Conger eel Conger myriaster off the Pacific coast south of Tohoku, north-eastern Japan

Seasonal changes were analyzed in the distribution of the conger eel Conger myriaster in the waters south of Tohoku, Japan, from Sendai Bay to the Joban coast, using catch per unit effort data of trawl vessels, and the relationship was examined between distribution and water temperature at 100 m depth, in 1999 and 2000. Although the conger eel was distributed throughout the study area, it was rare north of 37°40′N during February and March in both years. This scarcity corresponded to the occurrence of water colder than 10°C. Total length, age, gonad somatic index, and condition factor were not significantly different between eels caught north of 37°30′N and those caught south of 36°N. Therefore, the seasonal change in conger eel distribution within the study area seems to be a seasonal loop migration driven by avoidance of cold water.