Characteristics of Prey Environment during the Early Ocean Life of Juvenile Chum Salmon in Two Coastal Areas around Hokkaido, Northern Japan

Abstract Excerpt:
The early life stage of juvenile chum salmon in the ocean is a critical period in their life history. Their growth and survival in coastal waters are largely affected by physical factors, such as temperature, salinity, and ocean currents. Furthermore, since the quality and quantity of zooplankton as a prey source regulates juvenile growth, clarifying the characteristics of zooplankton used by juvenile chum salmon is important for growth and survival. To evaluate the prey environment during the early life stage of juvenile chum salmon in the ocean, we investigated the temporal dynamics of zooplankton community structure from spring to early summer in two coastal areas of Hokkaido, northern Japan. The first area was off Atsuta on the coast of the Sea of Japan, and the second was off Konbumori on the eastern Pacific coast.