AGGRESSIVENESS AND KINSHIP IN BROWN TROUT (SALMO-TRUTTA) PARR

In a series of experiments, kin-biased behavior of young brown trout ( Salmo trutta) was observed. The aggressiveness shown by groups of fami liar siblings (siblings reared together since fertilization) and group s of unfamiliar siblings (siblings reared apart since fertilization) w as significantly lower compared to that of mixed groups of two unrelat ed sibling groups (offspring of two different pairs of parents). The e volution of kin-biased behavior, as shown by a reduction in aggressive ness, is assumed to have evolved through a kin-selective mechanism.