The marginal increment growth in sagittal otoliths of the myctophid larvae Diaphus slender-type spp. collected in the north-eastern East China Sea was examined based on specimens collected at different times of the day. The calcification of the incremental zone began after midnight and took place throughout the day, and the discontinuous zone was formed only around midnight. These results indicate that otolith increments are formed daily. # 2005 The Fisheries Society of the British Isles

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 habitat conditions during the summer, from 2015 to 2017. Sardine in the offshore area had larger bodies and higher lipid contents than those in the coastal area. Regarding the sardine diet, lipid content of the offshore zooplankton was clearly higher than that of the coastal zooplankton. Hence, we found a positive effect of this dietary lipid content on sardine lipid content, suggesting that these lipid measurements could explain the trophic relationship between sardine and zooplankton. The higher lipid content in offshore zooplankton was mainly attributed to the abundance of large‐sized copepods and lower water temperatures. Such lipid measurements might involve habitat‐specific characteristics of zooplankton assemblage. In conclusion, compared to the coastal area, the offshore area is considered a more favorable habitat for the sardine in terms of lipid availability.

No abstract

No abstract