In situ swimming speeds of the late pelagic larvae of some Indo-Pacific coral-reef fishes

Abstract

S\~lmrnlng speeds of the late-stage, pelaglc larvae of coral-leef flshes were measured in situ near Llzard Island on Australia's Great Barrler Reef, and Ranglroa Atoll, Tuamotu Islands, French Polynes~a d u n n g 1995-96 Larvae were captured w~t h llght traps and crest nets, and released indiv~du-ally In open water They were then followed by SCUBA d~v e r s , normally for 10 mm, and their speed was measured w~t h a m o d~f~e d plankton-net flow meter and a stop watch Swlmmlng speeds of 260 lalvae of 50 specles In 15 famll~es of mostly perclform reef f~s h e s are presented Most measurements were for pomacentnds (8 genera 16 specles, 127 ~n d~v i d u a l s ) , apogonids (1 genus, -5 specles, 18 1nd1-vlduals), chaetodontids (3 genera. 8 specles, 49 ~ndlviduals), lethrlnlds (1 genus, -4 specles, 11 lndivlduals), nemipterlds ( l genus, 2 specles, 10 ~ndlvlduals), serranlds (2 genera, 2 specles, 14 md~vlduals) and acanthurlds (2 genera, -4 specles 13 ~n d~v l d u a l s )Numbers of lndlvlduals per specles ranged from 1 to 25 Speeds were remarkably hlgh for such small flshes ( 0 7 to 5 5 cm) Average speed was 20 6 cm S ' (ranqe 2 to 65), or 13 7 body lengths s ' (range 2 to 34) SE fol specles wlth n > 4 ranged from 0 8 to 5 3 cm s ' 14 1 to 25 0 " 0 of mean speed), but speed of the fastest lndlvldual ot each specles averaged 144 "/o of mean speed A taxonom~c component was evident, with apogonlds the slowest (2 to 13 cm S l ) , followed by nemipterlds (10 cm s ') Speed of pomacentr~ds and chaetodontlds varled wldely among specles (7 to 35 cm s '), whereas acanthunds, lethrlnlds and s e r r a n~d s were fast ( l 9 to 55 cm S-') Except for apogonlds and nem~ptel-lds, nearly all specles had mean swlmming speeds greater than average ambient current speeds In the L~zard Island area Mean speed was positively correlated wlth size (slope 8 2, r2 = 0 43) when all taxa were lncluded but was not correlated wlth slze for the Pomacentndae and Chaetodontidae when each were considered alone The speeds reported here combined wlth data on swimming endurance recently reported by Stobutzk~ & Bellwood (1997. Mar Ecol Prog Ser 149 35-41) reveal remarkable swlmnling a b l h t~e s for late-stage pelaglc larvae of coral-reef flshes whlch could e~t h e r gleatly enhance d~spersal or eliminate it

Movements of Marine Fish and Decapod Crustaceans: Process, Theory and Application

“…tidal flows, surface and subsurface currents and circulation) and active larval behaviour through horizontal and vertical movements (e.g. swimming, buuyancy control) (for fish see Boehlert and Mundy, 1988;Sponaugle and Cowen, 1997;Leis and Carson-Ewart, 1997;Forward et al, 1999;Epifanio and Garvine, 2001 and for crustaceans see Phillips, 1981;Sulkin, 1990;Young, 1995;Forward et al, 1997;Epifanio and Garvine, 2001). Interaction with water motion occurs at a range of scales, from near-substratum flow, which may influence the settlement process (centimetres-metres) (Butman, 1987;Breitburg et al, 1995) to Langmuir circulation and Ekman transport, tidal currents, internal waves, fronts, eddies and upwelling (100s metres-100s kilometres) (Phillips, 1981;Kingsford, et al, 1991;Shanks, 1995;Werner et al, 1997).…”

“…Leis and Carson-Ewart (1997) followed (using SCUBA) individual larvae of coral reef fish on the Great Barrier Reef and recorded their direction, depth and speed every 30 seconds. The authors found that there were inherent difficulties in visually tracking underwater since human observers have limited mobility in water compared to larval fish, with fish swimming speeds ranging from ~2 to 65 cms −1 and occasional rapid bursts of acceleration (Leis and Carson-Ewart, 1997). Underwater visual tracking is also limited to studies of animals that inhabit calm, clear and warm waters.…”

The structure of reef fish metapopulations: modelling larval dispersal and retention patterns

“…After this initial 'passive' period, larvae were assumed to enter an 'active' stage during which they are able to swim strongly enough to approach a reef (Stobutzki & Bellwood 1994Leis & Carson-Ewart 1997;Wolanski et al 1997). A baseline passive period of 14 days was used, as would apply for P. amboinensis (Fisher et al 2000).…”

Development of swimming abilities in reef fish larvae

“…40 body lengths (BL) s -1 . Leis et al (1996) and Leis & Carson-Ewart (1997) also recorded high swimming speeds, with capturerelease methods recording speeds of > 60 cm s -1 for reef fish larvae in the field. These speeds were maintained for several minutes.…”