Abstract
To provide fundamental knowledge for the sustainable use of fishery resources and the conservation of marine ecosystems, we investigated the distribution and abundance of fish larvae and juveniles in spring along the northern Hokkaido coast from the western Sea of Japan to the southern Sea of Okhotsk, Japan. A total of 38,736 individuals belonging to 32 taxa were collected using a frame trawl net (mean towing depth: 28.6 m) in April from 2010 to 2023, excluding 2013 and 2017. Gadus chalcogrammus consistently dominated the catches in most years, followed by Gymnocanthus spp. and Myoxocephalus spp. In 2014, exceptionally cold, low-salinity water prevailed, and Liparis agassizii was found in abundance, resulting in a distinctive taxonomic composition. Interannual fluctuations in the densities of several taxa were observed, including a notable decline in Lumpenus sagitta and an increased occurrence of Lepidopsetta mochigarei and Platichthys bicoloratus after 2015. Partial canonical correspondence analysis indicated that taxonomic composition was influenced by the Tsushima Warm Current, distance from major river mouths, and towing depth. In contrast, the effects of local temperature and salinity were not clearly discernible, possibly due to limitations in detecting their influence at small spatial and temporal scales.
