Feeding Habits of the Atka Mackerel Pleurogrammus monopterygius in Waters off the Central Kuril Islands

Resumo

The diet composition, stomach fullness, and condition factor of different size groups of the Atka mackerel Pleurogrammus monopterygius were studied in the area of the submarine plateau located in the Pacific waters off the central Kuril Islands, southeast of Onekotan Island, in June–July 1996. According to previously published data, mesopelagic fish forms the major part of the diet of Atka mackerel in this area, but the present study has revealed the leading role of Copepoda and Appendicularia, which is explained by different sites of material sampling: respectively, in the areas adjacent to the edge of the plateau and in its central part. It is assumed that the substantially lower condition factor of fish, as compared to previously published values, with the similar stomach fullness indices may result from the consumption of mainly low-calorie food (copepods and appendicularians).