ティラピア2種Oreochromis mossambicus, O.niloticusとその雑種から成る混群内での釣られ易さの固体差 Individual Catchability in the Mixed Group of Tilapia Species Oreochromis mossambicus, O.niloticus, and Their Hybrids
Mixed groups of two different species of tilapia <i>Oreochromis mossambicus, O. niloticus</i>, and their hybrids obtained from a river in Ibusuki city, Kagoshima pref. Japan were kept in two concrete tanks and evaluated for their vulnerability to angling. After capture-recapture angling tests, electrophoretic analysis was applied to all specimens to examine the effect of the degree of introgrssion of <i>O. mossambicus</i> and <i>O. niloticus</i> on the individual catchability. The most vulnerable group (three times hooked repeatedly) was composed mainly of <i>O. niloticus</i> and the least vulnerable one (three times unhooked repeatedly) was composed mainly of <i>O. mossambicus</i>. In the hybrids of these species, however, the most vulnerable specimens did not necessarily include more alleles orginally from <i>O. niloticus</i> than those from <i>O. mossambicus</i>, and there was no correlation between the degree of introgression and the catchability. This result implies that the individual catchability in hybrids is mostly determined by a posteriori rather than a priori.
日本水産学会誌 63(2), 166-170, 1997-03-15