AN ANALYSIS OF THE SUSTAINED SWIMMING ABILITIES OF PRESETTLEMENT AND POSTSETTLEMENT CORAL-REEF FISHES

A portable apparatus was developed to assess the sustained swimming abilities of juvenile reef fishes. Trials with the apparatus demonstrated its utility in the field and its ability to achieve water speeds of up to 70 cm . s-1. The critical swimming speed (U(c)) of pre- and post-settlement juveniles of three tropical pomacentrid taxa [Dischistodus spp., Pomacentrus amboinensis Bleeker and Neopomacentrus bankieri (Richardson)] were measured. There was no difference among the taxa in the U(c) of pre-settlement juveniles, with average U(c) values of 37.0, 43.7 and 45.5 cm . s-1, respectively. However, the pre-settlement juveniles displayed significantly higher U(c) values than immediate post-settlement juveniles, with pooled means of 38.2 and 26.3 cm . s-1 for pre- and post-settlement juveniles, respectively. The post-settlement individuals of all three taxa displayed a similar allometric coefficient describing the relationship between U(c) and total length.