Reproductive Biology of the Hard Shelled Mussel, Mytilus coruscus (Gould, 1861) in Ulleungdo Island in the East Sea

Abstract

The hard shelled mussel Mytilus coruscus (Gould, 1861) is a commercially important marine resource in Ulleungdo Island but there are very few studies about this species in this area. To provide fundamental information for future conservation and management, the reproductive biology such as gametogenesis of the hard shelled mussel in Ulleungdo Island in the East Sea were investigated monthly from May 2013 to May 2014. Gametogenesis commenced in male and female in September and October, respectively, when the water temperature reached 20.5&#8211 23.7°C. Ripe gametes were observed from February to May 2014 in both of sexes. The first discharge of gametes of males and females were observed in May 2013 and April 2014, and spawning continued until July in male and June in female. The condition index (CI), a calculated by tissue wet weight and internal shell cavity capacity, ranged from 0.084 (July) to 0.121 (May). The CI increased steadily from July (0.084) to March (0.105), then dropped in April (0.097) and peaked in May (0.121), indicating that mussel at Ulleungdo Island have spawning pulse in April 2014. Histology and the CI suggested that M. coruscus major spawning in Ulleungdo Island was in May 2013 and April 2014. According to the spawning pattern of M. coruscus in Ulleungdo Island suggested that the new fishing closure timing should be establish form March to June to protect early spawning broodstocks. The present n and management, the reproductive biology such as gametogenesis of the hard shelled mussel in Ulleungdo Island in the East Sea were investigated monthly from May 2013 to May 2014. Gametogenesis commenced in male and female in September and October, respectively, when the water temperature reached 20.5&#8211 23.7°C. Ripe gametes were observed from February to May 2014 in both of sexes. The first discharge of gametes of males and females were observed in May 2013 and April 2014, and spawning continued until July in male and June in female. The condition index (CI), a calculated by tissue wet weight and internal shell cavity capacity, ranged from 0.084 (July) to 0.121 (May). The CI increased steadily from July (0.084) to March (0.105), then dropped in April (0.097) and peaked in May (0.121), indicating that mussel at Ulleungdo Island have spawning pulse in April 2014. Histology and the CI suggested that M. coruscus major spawning in Ulleungdo Island was in May 2013 and April 2014. According to the spawning pattern of M. coruscus in Ulleungdo Island suggested that the new fishing closure timing should be establish form March to June to protect early spawning broodstocks. The present