Development of artificial insemination techniques for viviparous black rockfish (Sebastes schlegelii)

Abstract

Black rockfish (Sebastes schlegelii) is an economically important aquaculture species in Japan. Because it is a viviparous species, seedling production is typically performed using natural mating and the numbers of larva that are produced tend to be unstable. In the present study, we aimed to develop artificial insemination techniques for black rockfish to ensure stable seedling production. We used 20 female and 15 male mature individuals and examined when artificial insemination is best performed, in which diluent the sperm is best diluted and whether sperm collected from live or dead males both have fertilizing capability. The number of larvae produced by each pregnant female was counted. In addition, microsatellite markers were used to determine the relationship between larvae and parents. Following artificial insemination, 12 of 20 females became pregnant. The average litter size per pregnant female was about 130,000 fry. Pregnant females were obtained under all experimental conditions, regardless of season, sperm diluent and whether the male was live or dead. Paternity testing revealed that all larvae were produced by artificial insemination. Furthermore, females artificially inseminated by several males appeared to produce offspring derived from all males. The present study demonstrates that artificial insemination is possible in marine viviparous fish.