Chub mackerel, Scomber japonicus, is a cosmopolitan species that is widely distributed in the temperate waters of the Atlantic, Indian and Pacific oceans (HernandezandOrtega,2000). The mackerel is an important fishery resource for the numerous countries on the Pacific Ocean (ColletteandNauen,1983). In the waters around Japan, chub mackerel stocks decreased from 1980 before stabilizing at low levels after 2000.The commercial catch has been managed by the total allowable catch system (TAC) since 1997. Recently, chub mackerel have received considerable attention as a new target species in Japanese aquaculture. However, because seeding the mackerel used in aquaculture still depends on wild-caught adults, the captive rearing methods that are currently employed are not yet sustainable.