Ontogeny of in situ behaviours relevant to dispersal and population connectivity in larvae of coral-reef fishes

Abstract

Behaviour during the pelagic larval stage of coral-reef fishes can strongly influence dispersal, yet little is known of behavioural ontogeny. Speed, orientation and vertical distribution of larvae of 4 coral-reef fishes ( ) across the size range. All but the smallest, slowest larvae had Reynolds numbers >1000, and so swam in an inertial environment. In situ speeds were 39 to 87% of critical speeds, and smaller larvae swam nearer to critical speed than larger larvae. Of the larvae 71 to 90% swam directionally, but neither percentage of directional individuals nor orientation precision increased with size. P. teira swam toward the southwest (offshore). Epinephelus species undertook ontogenetic changes in orientation. Neither orientation nor ontogenetic changes were found in L. malabaricus. Horizontal swimming can influence dispersal directly. Vertical distribution, which differed among species, can influence dispersal indirectly. P. teira became surface orientated, ascending 0.8 m per mm increase in length. L. malabaricus descended 0.5 m per mm increase in length. E. coioides ascended 0.4 m per mm increase in length. E. fuscoguttatus preferred greater depths, and lacked ontogenetic changes. The behaviours and their development show these larval reef fishes can influence dispersal in speciesspecific ways.KEY WORDS: Connectivity · Dispersal · Larva · Ontogeny · Development · Coral reef · Fish · Serranidae · Lutjanidae · EphippidaeResale or republication not permitted without written consent of the publisher

Influence of starvation on the critical swimming behaviour of the Senegalese sole (<i>Solea senegalensis</i>) and its relationship with RNA/DNA ratios during ontogeny

“…Dudley et al, 2000;Guan et al, 2008), reporting an improvement in swimming performance until metamorphosis, after which improvements became slower. In disagreement with other studies Leis et al, 2006aLeis et al, ,b, 2007Leis et al, , 2009aFaria et al, 2009), we found no significant relationship between critical speed and size in any of the feeding treatments. This can be attributed to the small size range of tested larvae, or may be merely indicative of the poor swimming capacities of S. senegalensis larvae.…”

Ontogeny of swimming behaviour of two temperate clingfishes, Lepadogaster lepadogaster and L. purpurea (Gobiesocidae)

“…Recent in situ and laboratory studies have shown strong swimming capabilities in coral-reef fish larvae (e.g. Leis & Stobutzki 1999, Fisher & Bellwood 2002, Fisher 2005, Leis et al 2009a, which are sufficient to influence oceanic dispersal and return to adult habitats (e.g. Leis & Carson-Ewart 1997, Stobutzki & Bellwood 1997.…”

Paradigm Lost: Ocean Acidification Will Overturn the Concept of Larval-Fish Biophysical Dispersal

“…Although there is a significant increase in speed with size for both measures, the laboratory measure relationship explains 92% of the variation over the common size range whereas the in situ relationship explains only 54%. Data from Leis et al (2007Leis et al ( , 2009. (B) Ontogenetic change in in situ depth amplitude (difference between greatest and least depth) in larvae of a serranid, Epinephelus coioides.…”

“…Size of larvae is standard length (SL). Data from Leis et al (2009). (C) Frequency distribution of in situ orientation precision (r, length of the mean vector) of 33 individual larvae of a serranid, Epinephelus coioides.…”

“…Although both individuals have significantly directional swimming to the South-East, the one on the left (r = 0.43, p = 0.02) has a more meandering swim path than the one on the right (r = 0.89, p << 0.0001). Data from Leis et al (2009). The thin black radius is the mean direction, and the arc at its end is the 95% confidence interval.…”