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We investigated the reproductive capacity of starry flounder Platichthys stellatus from the Uljin (UJ) marine ranching area and compared it to that of P. stellatus from the coastal waters of Pohang (PH). In UJ, female gonadosomatic index (GSI) peaked in October () and male GSI was high in October and December. In PH, female GSI peaked in January () while male GSI began to increase in October and remained high until March. Most ovaries of UJ females were immature with perinucleus oocytes, although the testes of UJ males were ripe in January. Both the ovaries and testes of PH starry flounders were ripe from January to March. The plasma estradiol- () levels of UJ females were highest in October ( ng/mL) although the testosterone (T) levels of UJ males were highest in December ( ng/mL) and decreased gradually until April. The ,-dihydroxy-4-pregnen-3-one () levels of UJ females were not detected. The E2 levels of PH females were highest in December ( ng/mL) and levels were highest in March (5 ng/mL). The T levels of PH males were highest in December ( ng/mL) and decreased gradually until October. Taken together, these results suggest that most females from UJ did not reach maturation with a spawning period that was considered to be between December and January.

The common squid is a dominant species in Korean waters, where it is captured preponderantly by the angling fishery. The spawning and nursery grounds of extend from the southern East Sea to the northern East China Sea. Consequently, the environmental conditions in this area during the spawning and nursery seasons might affect the abundance of . This study, analyzed the relationship between the distribution of zooplankton and the abundance of and variation in the squid angling fishing grounds in Korean waters. There was a positive relationship between the fluctuations in zooplankton and the catch per unit effort (CPUE; ) of the angling fishery in the East Sea of Korea. The main fishing season is from July to December and the CPUE was closely related to the zooplankton biomass in April in the East Sea. Recently, the center of the squid jigging ground has moved drastically from the area around Ulleung Island to the northern East Sea. We postulate that the fishing grounds of the squid angling fishery will move farther north with climate change.