Japanese anchovy ( Engraulis japonicus ) is the most abundant fish in the East China Sea (ECS) and an important fishery resource throughout its life stages. Using samples collected along the ECS shelf‐break in April over a 22‐year period (2001–2022), we examined the horizontal distribution and interannual variability of larval density (mean standard length: 13.8–19.8 mm). High larval densities consistently occurred in the nort...

We compared the diet of larval Japanese sardine Sardinops melanostictus between the western and eastern areas of the Japanese coastal waters of the Sea of Japan in March–May 2019–2022. Standard lengths of larvae examined for gut contents ranged from 5 to 17 mm; in both areas, the main prey items found in the gut were copepod nauplii and copepodites. However, food incidence was low in eastern areas, and mean prey width differed...

The Japanese sardine ( Sardinops sagax melanostictus ) is a small pelagic fish found in the Sea of Japan, the marginal sea of the western North Pacific. It is an important species for regional fisheries, but their dispersal and migration patterns during early life stages remain unclear. In this study, we analyzed the stable oxygen isotope ratios of otoliths of young-of-the-year (age 0) Japanese sardines collected from the nort...

Recruitment of Japanese jack mackerel ( Trachurus japonicus ) has been decreasing continuously since 2000 in the Pacific coastal waters of Japan. The reasons and mechanisms for this phenomenon are still unclear. Particle‐tracking experiments were performed using a data assimilation model to elucidate the effect of a current system on the transportation processes of T. japonicus from the main spawning ground in the southern Eas...

Growth traits of juvenile Japanese jack mackerel ( Trachurus japonicus ) were estimated based on otolith daily increments in spring during 2011–2016 in the southwestern part of the Sea of Japan (SWSJ). Spatial variability in growth traits was examined between the western and eastern areas of the study area. Back‐calculated body length at 50 days post hatch varied among areas and years between 26 and 40 mm. Body lengths at age...

We examined interannual variations in the diet of Trachurus japonicus juveniles in relation to prey density and recent 5‐day instantaneous growth rate ( IGR ) in the southwestern part of the Sea of Japan (SJ) in late spring during 2011–2013. Habitat temperature of juveniles in 2011 was lower than the other 2 years. In all 3 years, more than 97% of juveniles had food in the stomach. Small juveniles Paracalanus parvus s.l., the...

Japanese sardine ( Sardinops melanostictus ) in the Sea of Japan expanded their distribution from the coast to offshore with an increase in population biomass; however, little is known about the suitability of the offshore habitat for this species. Using lipid analysis, this study compared the body condition of juvenile sardine between an area off the Noto Peninsula (offshore) and the Tsushima Strait (coast), with respect to h...

The western Pacific warm pool (WPWP) is a region of low nutrient and chlorophyll concentrations in which new production is generally considered to be supported by upward fluxes of nitrate from the deep water. A 19 d observation of nitrogen (N 2 ) fixation activity and diazotroph abundance along with primary production and nitrate assimilation rate was made at a fixed station in the WPWP. N 2 fixation activities accounted for l...