Laboratory-bred juvenile three-spined sticklebacks from II sibships did not
prefer to shoal with their siblings when they were offered the choice betw
een odor from unfamiliar siblings and non-kin in a fluviarium, although the
power for finding a significant preference was very high (0.99). The test
fish preferred the side where odor from the heavier shoal was supplied; thi
s shows that they could appreciate odor cues from conspecifics in our appar
atus and should have preferred their siblings if such a preference exists.
Our results are compatible with theoretical predictions but are at variance
with previous findings by other authors. We used independent replicates in
a blind protocol with strict randomization of fish and procedures.