528
12 Species Case Studies
and Planes and Fauvelot ( 2002 ) reported strong genetic stratifi cation of ocean
populations of convict surgeonfi sh across the Pacifi c, indicating limited dispersal
and self-recruitment in this species.
12.21.2 Reproductive Biology and Aggregation
Many species of surgeonfi shes are known to aggregate to spawn in most areas where
they occur, and aggregation-spawning is certainly a worldwide attribute of this family.
Records of aggregation-spawning are widespread geographically, and where there is
suffi cient information, most species exhibit consistent patterns of aggregation and
spawning throughout their ranges. No sex change is reported among any surgeonfi sh.
Acanthurus nigrofuscus – brown surgeonfi sh. The spawning of the brown surgeonfi sh has been examined in the Red Sea, the western Indian Ocean, Great Barrier
Reef, American Samoa, Palau and other locations (Johannes 1981 ; Robertson 1983 ;
Fishelson et al. 1987 ; Myrberg et al. 1988 ; Craig 1998 ; PLC unpublished data).
Robertson ( 1983 ) provided the fi rst information on aggregation and spawning from
three locations; Aldabra Atoll, Great Barrier Reef and Palau. In Palau, peak aggregation and spawning occurred on days just after mid- to late afternoon high tides
(co-occurring with the striped bristletooth) while no spawning was seen on days
with early morning high tides. Fish migrated a short distance from feeding areas, in
‘trains’ only a few metres wide. Pair spawning also occurred in feeding territories
of males and females, however some males which appeared to set up temporary territories near aggregation areas were not observed to pair-spawn.
Spectacular spawning aggregations of many thousands of brown surgeonfi sh off
Eilat, Israel in the northern Red Sea were initially documented by Myrberg et al.
( 1988 ) , Fishelson et al. ( 1987 ) and Kifl awi et al. ( 1998 ) . There two spawning aggregations of brown surgeonfi sh formed each afternoon during summer months (June–
August). The two aggregations were separated by about 1450 m along a fringing
reef slope. The fi sh in each aggregation spawn as a large group just before sunset
after migrating as much as 1.5 km from feeding grounds. Fishelson et al. ( 1987 )
found differences in the life history patterns of two populations of brown surgeonfi sh living close together. One population had to migrate daily between feeding and
resting grounds, while the second was resident in a single area which provided both
requirements. Tidal patterns, local currents and daily temperature variation showed
no relationship with spawning. Further work on the feeding ecology of the population has been published by Fishelson et al. ( 1987 ) and Montgomery et al. ( 1989 ) .
Fishelson et al. ( 1985 ) documented an unusual fat body external to the abdominal
cavity in several surgeonfi shes, including brown surgeonfi sh, which appears to serve
as an energy storage site to fuel gonadal function during the spawning season.
Mazeroll and Montgomery ( 1995, 1998 ) and Kifl awi and Mazeroll ( 2006 ) described
the migrations of brown surgeonfi sh to and from spawning aggregations (for more
detail see Chaps. 2 , 5 and 9 this volume).
While most records of aggregation have been from fore-reef environments,
Robertson ( 1983 ) reported one aggregation occurring at a channel mouth at Aldabra
12 Species Case Studies
and Planes and Fauvelot ( 2002 ) reported strong genetic stratifi cation of ocean
populations of convict surgeonfi sh across the Pacifi c, indicating limited dispersal
and self-recruitment in this species.
12.21.2 Reproductive Biology and Aggregation
Many species of surgeonfi shes are known to aggregate to spawn in most areas where
they occur, and aggregation-spawning is certainly a worldwide attribute of this family.
Records of aggregation-spawning are widespread geographically, and where there is
suffi cient information, most species exhibit consistent patterns of aggregation and
spawning throughout their ranges. No sex change is reported among any surgeonfi sh.
Acanthurus nigrofuscus – brown surgeonfi sh. The spawning of the brown surgeonfi sh has been examined in the Red Sea, the western Indian Ocean, Great Barrier
Reef, American Samoa, Palau and other locations (Johannes 1981 ; Robertson 1983 ;
Fishelson et al. 1987 ; Myrberg et al. 1988 ; Craig 1998 ; PLC unpublished data).
Robertson ( 1983 ) provided the fi rst information on aggregation and spawning from
three locations; Aldabra Atoll, Great Barrier Reef and Palau. In Palau, peak aggregation and spawning occurred on days just after mid- to late afternoon high tides
(co-occurring with the striped bristletooth) while no spawning was seen on days
with early morning high tides. Fish migrated a short distance from feeding areas, in
‘trains’ only a few metres wide. Pair spawning also occurred in feeding territories
of males and females, however some males which appeared to set up temporary territories near aggregation areas were not observed to pair-spawn.
Spectacular spawning aggregations of many thousands of brown surgeonfi sh off
Eilat, Israel in the northern Red Sea were initially documented by Myrberg et al.
( 1988 ) , Fishelson et al. ( 1987 ) and Kifl awi et al. ( 1998 ) . There two spawning aggregations of brown surgeonfi sh formed each afternoon during summer months (June–
August). The two aggregations were separated by about 1450 m along a fringing
reef slope. The fi sh in each aggregation spawn as a large group just before sunset
after migrating as much as 1.5 km from feeding grounds. Fishelson et al. ( 1987 )
found differences in the life history patterns of two populations of brown surgeonfi sh living close together. One population had to migrate daily between feeding and
resting grounds, while the second was resident in a single area which provided both
requirements. Tidal patterns, local currents and daily temperature variation showed
no relationship with spawning. Further work on the feeding ecology of the population has been published by Fishelson et al. ( 1987 ) and Montgomery et al. ( 1989 ) .
Fishelson et al. ( 1985 ) documented an unusual fat body external to the abdominal
cavity in several surgeonfi shes, including brown surgeonfi sh, which appears to serve
as an energy storage site to fuel gonadal function during the spawning season.
Mazeroll and Montgomery ( 1995, 1998 ) and Kifl awi and Mazeroll ( 2006 ) described
the migrations of brown surgeonfi sh to and from spawning aggregations (for more
detail see Chaps. 2 , 5 and 9 this volume).
While most records of aggregation have been from fore-reef environments,
Robertson ( 1983 ) reported one aggregation occurring at a channel mouth at Aldabra