Swim-training had a differential effect on on the age at appearance of bone structures between control and trained fish.

<p><b>A,B</b>) BF50<i>_age</i> values visualized in the corresponding structures in control fish (A) and trained fish (B). The branchial region is indicated separately, ventral view. <b>C</b>) Differences in BF50<i>_age</i> values between control and trained fish. Positive values indicate that structures appear earlier in the trained fish. Structures with a difference less than twice the standard error are indicated in grey.