Swimming performance and associated ionic disturbance of juvenile pink salmon Oncorhynchus gorbuscha determined using different acceleration profiles.

Swimming performance was assessed in juvenile pink salmon Oncorhynchus gorbuscha (body mass 0·05) among swim tests and ranged from 4·54 to 5·20 body lengths s−1. This result supports the hypothesis that at an early life stage, O. gorbuscha display the same fatigue speeds independent of the swimming test utilized. Whole body and plasma [Na+] and [Cl−] measured at the conclusion of these tests were significantly elevated when compared with control values (P < 0·05) and appear to be predominantly associated with dehydration rather than net ion gain. Given this finding for a small salmonid, estimates of swim performance can be accurately measured with acceleration tests lasting <10 min, allowing a more rapid processing than is possible with a longer critical swim speed test.