496
12 Species Case Studies
numerous anecdotal reports indicating major reductions in the abundances and catch
rates of B. muricatum shortly after the introduction of night spearfi shing (e.g. Dulvy
and Polunin 2004 ; Hamilton 2004 ; Sadovy 2007 ; Hamilton et al. 2010 ) . B. muricatum is presently listed as vulnerable following an IUCN 2010 Red List assessment.
In addition the species is actively being considered for listing as endangered or
threatened under the US Endangered Species Act through the National Marine
Fisheries Service NOAA.
In the western Pacifi c nocturnal spearfi shing is increasingly practiced with at
least 100 species targeted as it provides a greater CPUE than diurnal fi shing (Gillett
and Moy 2006 ) . Even though depleted, B. muricatum is a bonus for the nocturnal
fi sher so reduction in numbers will not curtail harvesting of this species. In the
Indian Ocean and Red Sea nocturnal spearfi shing is less likely to be practiced
although large numbers may be captured by netting schools in shallow water.
Although this species is not important in the international live reef fi sh trade, local
fi shing is suffi cient to deplete it across whole archipelagos and reef systems in the
Pacifi c and Indian Oceans (Dulvy and Polunin 2004 ) . Clearly there is no basis for
spawning closures as a management option for this species and it is unlikely that
any system of bag or size limits will be useful in management. The most effective
management option would be a species-level restriction on sales in local markets. If
the legislative machinery is available then establishment of no-take reserves is the
most appropriate option for longer-term protection. However given the size and
foraging range this would require a minimal reserve area ~ 6 km
2 .
Donaldson and Dulvy ( 2004 ) note that large size and known longevity indicate low
replacement rates and high vulnerability to fi shing. However this is not the problem
with respect to B. muricatum. Indeed there are many coral reef species with longer life
spans, slower growth rates and very low recruitment rates that are not in such a vulnerable position as this species. The recent assessment of extinction probabilities in
mammals (Davidson et al. 2009 ) shows that there are unique pathways to extinction
for species with different lifestyles and combinations of traits. These traits included
density, group size, body mass and habitat mode. In the case of B. muricatum specifi c
behavioural and foraging aspects of its biology and not life history parameters underlie its vulnerability. Consistent and predictable schooling behaviour associated with
all activities (foraging, spawning, sleeping), the cohesiveness of schools and their
restriction to shallow water makes this conspicuous species highly vulnerable to nocturnal and diurnal spearing and netting of foraging groups. In addition the well established negative relationship between body size and abundance means that this species
will be relatively rare over its considerable geographic range.
12.16 Longnose Parrotfi sh – Hipposcarus longiceps
Patrick L. Colin
Coral Reef Research Foundation, PO Box 1765 , Koror , Palau 96940
e-mail: crrf@palaunet.com
12 Species Case Studies
numerous anecdotal reports indicating major reductions in the abundances and catch
rates of B. muricatum shortly after the introduction of night spearfi shing (e.g. Dulvy
and Polunin 2004 ; Hamilton 2004 ; Sadovy 2007 ; Hamilton et al. 2010 ) . B. muricatum is presently listed as vulnerable following an IUCN 2010 Red List assessment.
In addition the species is actively being considered for listing as endangered or
threatened under the US Endangered Species Act through the National Marine
Fisheries Service NOAA.
In the western Pacifi c nocturnal spearfi shing is increasingly practiced with at
least 100 species targeted as it provides a greater CPUE than diurnal fi shing (Gillett
and Moy 2006 ) . Even though depleted, B. muricatum is a bonus for the nocturnal
fi sher so reduction in numbers will not curtail harvesting of this species. In the
Indian Ocean and Red Sea nocturnal spearfi shing is less likely to be practiced
although large numbers may be captured by netting schools in shallow water.
Although this species is not important in the international live reef fi sh trade, local
fi shing is suffi cient to deplete it across whole archipelagos and reef systems in the
Pacifi c and Indian Oceans (Dulvy and Polunin 2004 ) . Clearly there is no basis for
spawning closures as a management option for this species and it is unlikely that
any system of bag or size limits will be useful in management. The most effective
management option would be a species-level restriction on sales in local markets. If
the legislative machinery is available then establishment of no-take reserves is the
most appropriate option for longer-term protection. However given the size and
foraging range this would require a minimal reserve area ~ 6 km
2 .
Donaldson and Dulvy ( 2004 ) note that large size and known longevity indicate low
replacement rates and high vulnerability to fi shing. However this is not the problem
with respect to B. muricatum. Indeed there are many coral reef species with longer life
spans, slower growth rates and very low recruitment rates that are not in such a vulnerable position as this species. The recent assessment of extinction probabilities in
mammals (Davidson et al. 2009 ) shows that there are unique pathways to extinction
for species with different lifestyles and combinations of traits. These traits included
density, group size, body mass and habitat mode. In the case of B. muricatum specifi c
behavioural and foraging aspects of its biology and not life history parameters underlie its vulnerability. Consistent and predictable schooling behaviour associated with
all activities (foraging, spawning, sleeping), the cohesiveness of schools and their
restriction to shallow water makes this conspicuous species highly vulnerable to nocturnal and diurnal spearing and netting of foraging groups. In addition the well established negative relationship between body size and abundance means that this species
will be relatively rare over its considerable geographic range.
12.16 Longnose Parrotfi sh – Hipposcarus longiceps
Patrick L. Colin
Coral Reef Research Foundation, PO Box 1765 , Koror , Palau 96940
e-mail: crrf@palaunet.com