518
12 Species Case Studies
12.20.1 General
While the surgeonfi shes (Acanthuridae) are found worldwide in tropic and warm
temperate waters, only two species which occur in the tropical Western Atlantic;
Acanthurus bahianus (ocean surgeon) and Acanthurus coeruleus (blue tang) are
considered here (Fig. 12.56 ). A third species, Acanthurus chirurgus (doctorfi sh), is
not covered in detail.
Surgeonfi shes are not important commercial food fi shes in the western
Atlantic, but are commonly taken in trap fi sheries, mostly for subsistence use.
Wide variation in growth rates and maximal sizes across the geographic range
of the species has been reported (Robertson et al. 2005a ) . Densities of fi sh on
different reef systems range from 1 to 16 (averaging 5) fi sh per 100 m
2 (Robertson
et al. 2005b ) .
Surgeonfi shes are herbivores whose constant grazing on the reef helps keep populations of algae in check and leaves areas clear for invertebrate larvae to settle.
Despite their importance in reef fi sh communities, surprisingly little has been written regarding the reproduction, particularly their spawning biology, of Atlantic species. Their biology was last reviewed by Reeson ( 1983 ) and information on spawning
aggregations had not been published at that time. Other aspects of their life histories
have received some attention (Robertson 1988a, b ; Robertson et al. 2005a, b ; Rocha
et al. 2002 ) .
Reeson ( 1983 ) reported ocean surgeonfi sh to fi rst mature at about 92 mm total
length (TL) while most fi shes probably mature at about 126–134 mm TL and the
largest fi sh was about 200 mm TL (sexes not reported). Blue tang matured starting
at 109 mm TL, with most fi shes mature at 120–130 mm TL and the largest fi sh were
220–240 mm TL. Robertson ( 1988a, b ) believed that Atlantic surgeonfi shes in
Panama reach sexual maturity about 2 years after settlement and can live up to about
10 years. Robertson et al. ( 2005a ) found ocean surgeonfi sh to have the highest
recorded growth rate for a surgeonfi sh, and corroborated a 10 year age for large fi sh
from Belize. They also showed that fi sh in other locations may achieve considerably
longer lives, as much as 30 years in Bermuda.
12.20.2 Aggregation and Spawning
Resident spawning aggregations were fi rst discovered, by chance, by the authors in
December 1976 in Puerto Rico and have now been reported (Colin and Clavijo
1988 ; Colin 1996 ; Deloach 1999 ) for all three species; ocean surgeonfi sh (Puerto
Rico), blue tang (Puerto Rico, The Bahamas, Belize) and doctorfi sh (Belize). Pairspawning is also known in all three species, often occurring at the same sites and
times as aggregation spawning.
After the initial discovery of the Puerto Rican aggregations, we undertook a
study from late 1977 through 1980 to document the locations, timing and general
12 Species Case Studies
12.20.1 General
While the surgeonfi shes (Acanthuridae) are found worldwide in tropic and warm
temperate waters, only two species which occur in the tropical Western Atlantic;
Acanthurus bahianus (ocean surgeon) and Acanthurus coeruleus (blue tang) are
considered here (Fig. 12.56 ). A third species, Acanthurus chirurgus (doctorfi sh), is
not covered in detail.
Surgeonfi shes are not important commercial food fi shes in the western
Atlantic, but are commonly taken in trap fi sheries, mostly for subsistence use.
Wide variation in growth rates and maximal sizes across the geographic range
of the species has been reported (Robertson et al. 2005a ) . Densities of fi sh on
different reef systems range from 1 to 16 (averaging 5) fi sh per 100 m
2 (Robertson
et al. 2005b ) .
Surgeonfi shes are herbivores whose constant grazing on the reef helps keep populations of algae in check and leaves areas clear for invertebrate larvae to settle.
Despite their importance in reef fi sh communities, surprisingly little has been written regarding the reproduction, particularly their spawning biology, of Atlantic species. Their biology was last reviewed by Reeson ( 1983 ) and information on spawning
aggregations had not been published at that time. Other aspects of their life histories
have received some attention (Robertson 1988a, b ; Robertson et al. 2005a, b ; Rocha
et al. 2002 ) .
Reeson ( 1983 ) reported ocean surgeonfi sh to fi rst mature at about 92 mm total
length (TL) while most fi shes probably mature at about 126–134 mm TL and the
largest fi sh was about 200 mm TL (sexes not reported). Blue tang matured starting
at 109 mm TL, with most fi shes mature at 120–130 mm TL and the largest fi sh were
220–240 mm TL. Robertson ( 1988a, b ) believed that Atlantic surgeonfi shes in
Panama reach sexual maturity about 2 years after settlement and can live up to about
10 years. Robertson et al. ( 2005a ) found ocean surgeonfi sh to have the highest
recorded growth rate for a surgeonfi sh, and corroborated a 10 year age for large fi sh
from Belize. They also showed that fi sh in other locations may achieve considerably
longer lives, as much as 30 years in Bermuda.
12.20.2 Aggregation and Spawning
Resident spawning aggregations were fi rst discovered, by chance, by the authors in
December 1976 in Puerto Rico and have now been reported (Colin and Clavijo
1988 ; Colin 1996 ; Deloach 1999 ) for all three species; ocean surgeonfi sh (Puerto
Rico), blue tang (Puerto Rico, The Bahamas, Belize) and doctorfi sh (Belize). Pairspawning is also known in all three species, often occurring at the same sites and
times as aggregation spawning.
After the initial discovery of the Puerto Rican aggregations, we undertook a
study from late 1977 through 1980 to document the locations, timing and general