208
P.L. Colin
Settling fi sh may “try out” a reef and then quickly return to the water column,
not remaining on the fi rst reef they encounter. Once a suitable settlement location
is found, the juvenile undergoes metamorphosis, in which it changes its body
structure and physiology, losing structures that contribute to survival in the pelagic
(transparency, spination), and acquire characters useful in the benthic, environment
(pigmention, changes in mouth orientation, changes in alimentary tract for a different
diet). Some evidence suggests that fi shes stop feeding during metamorphosis, using
internal reserves to support themselves for a period of several days.
The settlement behaviour and selection of settlement habitat of some aggregation
spawning predatory fi shes have been examined (Eggleston 1995 ; Wright et al. 2005 ;
Nakamura et al. 2009 ) . Quere and Leis ( 2010 ) found the Spanish fl ag snapper,
Lutjanus caponotatus, to have complex settlement behaviour with strong swimming
capabilities and the ability to interact with a variety of reef residents. Leis and
Carson-Ewart ( 1999 ) reported similar settlement behaviour in the squaretail
coralgrouper, Plectropomus areolatus .
In the absence of a suitable reef, or any reef at all, how long can pelagic juveniles
persist in the plankton? It appears that different species have different tolerances for
extension of pelagic life (McCormick 1999b ; Leis and McCormick 2002 ) . For some
aggregating species they seem to have fairly high limits, if the largest size of
pelagic stages is any indication. Among groupers, Smith ( 1971 : 77) reported two
transparent “late larvae”, one a Nassau grouper 45.6 mm long and a mutton hamlet,
Epinephelus afer , 37.5 mm long (whether standard or total length not indicated),
taken 8 miles from land in Bermuda and kept in aquaria until they transformed.
Randall ( 1956 ) noted pelagic surgeonfi sh larvae (acronurus) as large as 60 mm
(average size for settlement about 26 mm SL). Lara et al ( 2009 ) provided evidence
of delayed metamorphosis in goliath grouper, E. itajara , with larval life, based on
otolith increments and settlement marks, ranging from a low of around 30 days to as
high as 60–72 days. Experimental evidence of delayed metamorphosis is uncommon.
However, McCormick ( 1999a, b ) caught settlement-ready convict surgeonfi sh,
Acanthurus triostegus , acronuri at night and held them at 3–6 m depth over a 50 m
deep bottom inside moored monofi lament net cages which delayed their metamorphosis. Control fi sh, held in benthic cages, metamorphosed within 5 days.
The larval biology of freckled goatfi sh, Upeneus tragula , a widespread IWP
goatfi sh, may be of particular relevance, since it has pelagic eggs. While it has not
been observed to aggregate for spawning (some other goatfi shes do), it is possible it
will be found to aggregate, or that its ELH is similar to aggregating goatfi shes.
McCormick and Molony ( 1995 ) found in an experimental study that larvae of freckled
goatfi sh settled earlier in warmer water with shorter body length and reduced body
depth than those reared in cooler water.
7.6.2 Swimming Capabilities and ELH of Reef Fishes
Fisher ( 2005 ) indicated that larval reef fi shes for several families would be able to
“substantially infl uence their dispersal pattern” through swimming for the last half
P.L. Colin
Settling fi sh may “try out” a reef and then quickly return to the water column,
not remaining on the fi rst reef they encounter. Once a suitable settlement location
is found, the juvenile undergoes metamorphosis, in which it changes its body
structure and physiology, losing structures that contribute to survival in the pelagic
(transparency, spination), and acquire characters useful in the benthic, environment
(pigmention, changes in mouth orientation, changes in alimentary tract for a different
diet). Some evidence suggests that fi shes stop feeding during metamorphosis, using
internal reserves to support themselves for a period of several days.
The settlement behaviour and selection of settlement habitat of some aggregation
spawning predatory fi shes have been examined (Eggleston 1995 ; Wright et al. 2005 ;
Nakamura et al. 2009 ) . Quere and Leis ( 2010 ) found the Spanish fl ag snapper,
Lutjanus caponotatus, to have complex settlement behaviour with strong swimming
capabilities and the ability to interact with a variety of reef residents. Leis and
Carson-Ewart ( 1999 ) reported similar settlement behaviour in the squaretail
coralgrouper, Plectropomus areolatus .
In the absence of a suitable reef, or any reef at all, how long can pelagic juveniles
persist in the plankton? It appears that different species have different tolerances for
extension of pelagic life (McCormick 1999b ; Leis and McCormick 2002 ) . For some
aggregating species they seem to have fairly high limits, if the largest size of
pelagic stages is any indication. Among groupers, Smith ( 1971 : 77) reported two
transparent “late larvae”, one a Nassau grouper 45.6 mm long and a mutton hamlet,
Epinephelus afer , 37.5 mm long (whether standard or total length not indicated),
taken 8 miles from land in Bermuda and kept in aquaria until they transformed.
Randall ( 1956 ) noted pelagic surgeonfi sh larvae (acronurus) as large as 60 mm
(average size for settlement about 26 mm SL). Lara et al ( 2009 ) provided evidence
of delayed metamorphosis in goliath grouper, E. itajara , with larval life, based on
otolith increments and settlement marks, ranging from a low of around 30 days to as
high as 60–72 days. Experimental evidence of delayed metamorphosis is uncommon.
However, McCormick ( 1999a, b ) caught settlement-ready convict surgeonfi sh,
Acanthurus triostegus , acronuri at night and held them at 3–6 m depth over a 50 m
deep bottom inside moored monofi lament net cages which delayed their metamorphosis. Control fi sh, held in benthic cages, metamorphosed within 5 days.
The larval biology of freckled goatfi sh, Upeneus tragula , a widespread IWP
goatfi sh, may be of particular relevance, since it has pelagic eggs. While it has not
been observed to aggregate for spawning (some other goatfi shes do), it is possible it
will be found to aggregate, or that its ELH is similar to aggregating goatfi shes.
McCormick and Molony ( 1995 ) found in an experimental study that larvae of freckled
goatfi sh settled earlier in warmer water with shorter body length and reduced body
depth than those reared in cooler water.
7.6.2 Swimming Capabilities and ELH of Reef Fishes
Fisher ( 2005 ) indicated that larval reef fi shes for several families would be able to
“substantially infl uence their dispersal pattern” through swimming for the last half