531
12 Species Case Studies
time period (Colin 1996 ; Mazeroll and Montgomery 1998 ; Robertson 1983 ) . Sancho
et al. ( 2000a, b ) found the presence of caudal spines does not deter the low level of
predation on spawning adult surgeonfi shes; levels of successful predation on bluelined surgeonfi sh, Acanthurus nigroris , at Johnston Island were similar to that on
parrotfi shes, which lack the caudal spines. In addition to brown surgeonfi sh, information is available for the following species:
Acanthurus triostegus – Convict surgeonfi sh (manini) . The exceptionally common convict surgeonfi sh is found on reef fl ats throughout the Indo-west Pacifi c
region and was the fi rst species of Acanthurus to have its spawning documented.
Randall ( 1961a ) reported on both pair- and group-spawning in Hawaii, and later
Polynesia (Randall 1961b ) . Johannes ( 1981 ) reported aggregations to occur at the
outer end of a channel through the barrier reef in Palau between the “fourth and
tenth of the lunar month” between May and August, and perhaps to a lesser extent
in other months. Robertson ( 1983 ) observed group- (and pair-) spawning on ebb
tides in Aldabra Atoll, Palau and the Great Barrier Reef and illustrated colour patterns. Craig ( 1998 ) found convict surgeonfi sh spawning in reef channels during
early morning in American Samoa, where it co-occurs with aggregations of whitespotted surgeonfi sh, Acanthurus guttatus (Fig. 12.67 ).
Acanthurus lineatus – blue-banded surgeonfi sh. This is extremely common on
shallow outer reefs. Johannes ( 1981 ) observed early morning aggregation spawning
in April at the south end of Peleliu, Palau while Robertson ( 1983 ) also documents
its early morning spawning elsewhere in Palau on shallow fore reefs. Robertson
( 1983 ) also saw a few group-spawns and one pair-spawn. The species has never
been seen to spawn at other that in the morning, either as pairs or groups.
Acanthurus nigroris – blue-lined surgeonfi sh . During extensive observations at
Johnston Island, Sancho et al. ( 2000a ) recorded more total spawns (all group
spawns) by this species than any other, except bullethead parrotfi sh, Chlorurus sordidus , (even pair spawning species). Blue-lined surgeonfi sh spawned only for a portion of the lunar month, plus the channel where they were studied had unidirectional
Fig. 12.67 ( a, b ) Aggregations of white-spotted surgeonfi sh, Acanthurus guttatus , and convict
surgeonfi sh, Acanthurus triostegus , occur in reef channels in American Samoa (Photos: © Peter C.
Craig)
12 Species Case Studies
time period (Colin 1996 ; Mazeroll and Montgomery 1998 ; Robertson 1983 ) . Sancho
et al. ( 2000a, b ) found the presence of caudal spines does not deter the low level of
predation on spawning adult surgeonfi shes; levels of successful predation on bluelined surgeonfi sh, Acanthurus nigroris , at Johnston Island were similar to that on
parrotfi shes, which lack the caudal spines. In addition to brown surgeonfi sh, information is available for the following species:
Acanthurus triostegus – Convict surgeonfi sh (manini) . The exceptionally common convict surgeonfi sh is found on reef fl ats throughout the Indo-west Pacifi c
region and was the fi rst species of Acanthurus to have its spawning documented.
Randall ( 1961a ) reported on both pair- and group-spawning in Hawaii, and later
Polynesia (Randall 1961b ) . Johannes ( 1981 ) reported aggregations to occur at the
outer end of a channel through the barrier reef in Palau between the “fourth and
tenth of the lunar month” between May and August, and perhaps to a lesser extent
in other months. Robertson ( 1983 ) observed group- (and pair-) spawning on ebb
tides in Aldabra Atoll, Palau and the Great Barrier Reef and illustrated colour patterns. Craig ( 1998 ) found convict surgeonfi sh spawning in reef channels during
early morning in American Samoa, where it co-occurs with aggregations of whitespotted surgeonfi sh, Acanthurus guttatus (Fig. 12.67 ).
Acanthurus lineatus – blue-banded surgeonfi sh. This is extremely common on
shallow outer reefs. Johannes ( 1981 ) observed early morning aggregation spawning
in April at the south end of Peleliu, Palau while Robertson ( 1983 ) also documents
its early morning spawning elsewhere in Palau on shallow fore reefs. Robertson
( 1983 ) also saw a few group-spawns and one pair-spawn. The species has never
been seen to spawn at other that in the morning, either as pairs or groups.
Acanthurus nigroris – blue-lined surgeonfi sh . During extensive observations at
Johnston Island, Sancho et al. ( 2000a ) recorded more total spawns (all group
spawns) by this species than any other, except bullethead parrotfi sh, Chlorurus sordidus , (even pair spawning species). Blue-lined surgeonfi sh spawned only for a portion of the lunar month, plus the channel where they were studied had unidirectional
Fig. 12.67 ( a, b ) Aggregations of white-spotted surgeonfi sh, Acanthurus guttatus , and convict
surgeonfi sh, Acanthurus triostegus , occur in reef channels in American Samoa (Photos: © Peter C.
Craig)