377
11 Management of Spawning Aggregations
seasonal ban on the possession and sale of certain fi sh species may afford some
protection, the addition of seasonal protection of their aggregation sites can further
limit fi shing mortality during the period of greatest vulnerability. A minimum fi sh
size limit can also ensure that fi sh grow large enough to reproduce before recruiting
to a fi shery, irrespective of where and when the species is fi shed. There are several
examples of multiple measures being applied to aggregating spawners (e.g. red
hind: Luckhurst and Trott 2009 ; leopard coralgrouper, Plectropomus leopardus :
Russell 2006 ; Nassau grouper: Bahamas, Cuba, Belize, Cayman Islands, Sadovy
and Eklund 1999 ; Whaylen et al. 2004 ; Claro et al. 2009 ; Janet Gibson personal
communication 2010, Table 11.1 , Chaps. 12.3 , 12.6 , and 12.9 ).
Once management is in place, assessment of the effectiveness of management
measures is essential to ensure suffi cient protection and to demonstrate outcomes to
the fi shing and wider community. However, variable enforcement effectiveness and
the confounding effects of having a range of management measures within a
particular fi shery can complicate assessments of management effectiveness. For
example, a highly valued fi shery for leopard coralgrouper in Australia has a combination of management measures including quotas, minimum size limits, MPAs and
aggregation season protection. In 2008, after considerable debate including stakeholder workshops, the aggregation season protection was downgraded largely
because of concerns in the fi shing community about the impacts of the global economic crisis. This was a reactive management decision not based on biological
demonstration of stock status or effectiveness of existing measures, but due to pressure placed on government to remove spawning season closures given the many
other restrictive management arrangements in place. Moreover, there was little evidence from fi shery-dependent data that aggregations were being targeted (Chap.
12.9 ). In the Bahamas, the Nassau grouper aggregation protection was likewise
down-graded in response to similar concerns in 2008.
The most appropriate management for a particular location or species inevitably
depends on local social and economic factors, as well as can the biology and conservation status of the target species, and is best made on a case-by-case basis.
Protection may also need to be implemented both during and outside of aggregation
periods. There are many potential mixes of management options, and all options
require effective enforcement and monitoring on a long-term basis to allow for
adaptive management, which is fundamental in any attempt to manage a complex
system of biological, ecological, economic and social variables. It is important to
ensure that management is planned for the long term. Many of the fi sh species vulnerable to overfi shing are long-lived and slow to recover, requiring long-term management planning. For example, since protection in 2002 was established for Nassau
grouper aggregations in the Cayman Islands there are only now indications of
increasing numbers of fi sh according to diver surveys, mark-and-recapture data, and
video laser observations (Scott Heppell personal observation 2010, Table 11.1 ).
Given the long-lived nature of Nassau grouper, more time is likely to see larger
benefi ts from protection.
Management can occur at the species or ecosystem level with special attention
given to threatened species or habitats. Species-specifi c protection is useful when
information on aggregation sites and timing are lacking, incomplete or liable to
11 Management of Spawning Aggregations
seasonal ban on the possession and sale of certain fi sh species may afford some
protection, the addition of seasonal protection of their aggregation sites can further
limit fi shing mortality during the period of greatest vulnerability. A minimum fi sh
size limit can also ensure that fi sh grow large enough to reproduce before recruiting
to a fi shery, irrespective of where and when the species is fi shed. There are several
examples of multiple measures being applied to aggregating spawners (e.g. red
hind: Luckhurst and Trott 2009 ; leopard coralgrouper, Plectropomus leopardus :
Russell 2006 ; Nassau grouper: Bahamas, Cuba, Belize, Cayman Islands, Sadovy
and Eklund 1999 ; Whaylen et al. 2004 ; Claro et al. 2009 ; Janet Gibson personal
communication 2010, Table 11.1 , Chaps. 12.3 , 12.6 , and 12.9 ).
Once management is in place, assessment of the effectiveness of management
measures is essential to ensure suffi cient protection and to demonstrate outcomes to
the fi shing and wider community. However, variable enforcement effectiveness and
the confounding effects of having a range of management measures within a
particular fi shery can complicate assessments of management effectiveness. For
example, a highly valued fi shery for leopard coralgrouper in Australia has a combination of management measures including quotas, minimum size limits, MPAs and
aggregation season protection. In 2008, after considerable debate including stakeholder workshops, the aggregation season protection was downgraded largely
because of concerns in the fi shing community about the impacts of the global economic crisis. This was a reactive management decision not based on biological
demonstration of stock status or effectiveness of existing measures, but due to pressure placed on government to remove spawning season closures given the many
other restrictive management arrangements in place. Moreover, there was little evidence from fi shery-dependent data that aggregations were being targeted (Chap.
12.9 ). In the Bahamas, the Nassau grouper aggregation protection was likewise
down-graded in response to similar concerns in 2008.
The most appropriate management for a particular location or species inevitably
depends on local social and economic factors, as well as can the biology and conservation status of the target species, and is best made on a case-by-case basis.
Protection may also need to be implemented both during and outside of aggregation
periods. There are many potential mixes of management options, and all options
require effective enforcement and monitoring on a long-term basis to allow for
adaptive management, which is fundamental in any attempt to manage a complex
system of biological, ecological, economic and social variables. It is important to
ensure that management is planned for the long term. Many of the fi sh species vulnerable to overfi shing are long-lived and slow to recover, requiring long-term management planning. For example, since protection in 2002 was established for Nassau
grouper aggregations in the Cayman Islands there are only now indications of
increasing numbers of fi sh according to diver surveys, mark-and-recapture data, and
video laser observations (Scott Heppell personal observation 2010, Table 11.1 ).
Given the long-lived nature of Nassau grouper, more time is likely to see larger
benefi ts from protection.
Management can occur at the species or ecosystem level with special attention
given to threatened species or habitats. Species-specifi c protection is useful when
information on aggregation sites and timing are lacking, incomplete or liable to