Relative swimming speeds in reef fish larvae

Abstract

In most organisms relative locomotor speed (body lengths per second [bls–1]) is inversely proportional to body size. The ability of late stage reef fish larvae to achieve swimming speeds of over 40 bls–1 is consistent with this general scaling relationship. However, this relationship does not extend to smaller larvae which are not fully developed. Maximum critical swimming speeds appear to be limited by both developmental stage and size. At 7 mm total length when settling, the unusually small larvae of anemonefishes are able to sustain speeds of 49 bls–1. This probably approaches the maximum limit for sustained aquatic vertebrate locomotion.