Feeding of masu salmon <i>Oncorhynchus masou</i> in the Okhotsk Sea in autumn

Abstract

Feeding habits of masu salmon Oncorhynchus masou in the Okhotsk Sea is investigated. Its main prey in fall season is fish, amphipods, and euphausiids. However, the diet composition depends on the area: for masu with size of 30-40 cm it is mainly fish in the biostatistical districts 8 and 11 and zooplankton in other areas; besides, the zooplankton prey is replaced by fish for elder and larger salmons. The stomach fullness has significant circadian rhythm with one main maximum (70-700 ‱) and one minor peak. The main maximum was observed at 21 o’clock in 2002 but at 15 o’clock in 2006 and at 18 o’clock in 2009 and 2015 (local time).

Keywords

• сима
• питание рыб
• зоопланктон
• индекс наполнения желудка
• охотское море