A. Risk, EFFECTS OF HABITAT ON THE SETTLEMENT AND POST SETTLEMENT SUCCESS OF THE OCEAN SURGEONFISH ACANTHURUS-BAHIANUS, Marine ecology. Progress series, 161, 1997, pp. 51-59
Local population dynamics of fishes on coral reefs are dependent on pr
ocesses affecting the settlement of pelagic larvae and the subsequent
persistence of these new settlers. The ability of larvae to choose fav
ourable places to settle in terms of persistence may make the dynamics
of certain populations predictable at the reef scale, and cause patte
rns of recruitment to differ from those of larval supply. I collected
data on settlement, recruitment and persistence of the ocean surgeonfi
sh Acanthurus bahianus in different physiographic zones of the Tague B
ay reef, on the island of St. Croix, U.S. Virgin Islands. There was si
gnificantly higher settlement and recruitment to the back-reef zone th
an to the fore-reef zone or seagrass zones at the bases of the back-re
ef and fore-reef, suggesting that larvae select settlement sites and d
o not necessarily settle to the first reef zone encountered. On the ba
ck-reef, settlers used pavement more than any other type of substratum
, and the post-settlement persistence of settlers and recruits was hig
hest on pavement when compared to these other substrata. These results
suggest that patterns of ocean surgeonfish settlement are affected by
reef-based processes, and that selection for certain zones and substr
ata occurs. Subsequent modification of these initial settlement patter
ns by increased persistence in preferred habitats adds predictability
to patterns of recruitment, resulting in larval supply alone being an
insufficient explanation of the distribution and abundance of ocean su
rgeonfish populations at this scale.