Meeting Abstract
Reef fish larvae were once considered passive particles dispersed by currents for 10’s to 100’s of km. However, recent studies using genetic parentage analyses reveal that the larvae of several fish species rarely disperse farther than 10 km from their natal origin. This gap between predicted and observed patterns of larval dispersal suggests that other factors, such as swimming and orientation behavior, play a role in shaping the pattern of dispersal. Yet, few studies have investigated the development of swimming abilities in reef fish larvae. In this study, the development of critical and sustained swimming abilities was measured in the larvae of two species of reef fish with similar patterns of short distance dispersal. Specifically, we investigated the effect of i) species, ii) age, and iii) morphology on the development of critical and sustained swimming abilities in lab-reared Amphiprion percula and Elacatinus lori larvae from hatching through settlement. To test critical swimming speed, larvae were exposed to incremental increases in current speed at 2 min intervals until they could no longer maintain position in the flume. To test sustained swimming performance, replicate trials were conducted at 2, 4, 6, 8 and 10 cm s-1 and the time until exhaustion was recorded. For both species, swimming abilities increase with age, standard length and propulsive area. Swimming abilities differed substantially between species, with A. percula displaying greater critical and sustained swimming abilities than E. lori at all ages. This dramatic difference in larval swimming abilities is surprising given the similarity in the pattern of dispersal and suggests that these species may use different behavioral strategies to remain close to their natal reef.
