Behaviour of juvenile red sea bream after stocking
1993
Yamaoka, K.(Kochi Univ., Nankoku (Japan). Faculty of Agriculture)
Behavioral features of artificially-bred juvenile red sea bream after stocking were reviewed. Several marking methods which have been used for stocking program were also evaluated by adopting the territorial behavior as a behavioral index. The pigment injection method showed the least effect on their behavior and was suggested to be the best marking method. After first stocking, three types of individuals showing distinct behavior were distinguished: 1) territorial individuals, 2) territory-like individuals, 3) individuals keeping no restricted cruising area. Just after stocking, all fish were the type 3). Then, fish of the types 1) and 2) increased in number gradually and became almost constant, which suggests that there exists a carrying capacity for the released population of red sea bream. However, the types 1) and 2) did not show a distinct increase in the second stocking. The differences in the recruitment pattern between the first and second stocking groups suggest that the effect of prior residence works, intermediated by the territorial behavior.
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