49
2 Ecosystem Aspects of Species That Aggregate to Spawn
from habitat damage, and the direct and indirect impacts of fi shing activities is critical
for the long-term sustainability of spawning aggregations.
How these spatially distinct components are incorporated into management plans
will depend upon management objectives, priorities and capabilities. For example,
for a species whose population is being fi shed sustainably (either because fi shing
effort is low or the fi shery is well-managed), protecting the core spawning site and
courtship arena during the spawning season may be adequate. For species or populations that are heavily fi shed, incorporating the staging area into a no-fi shing zone
may be the most appropriate course of action. If data are available, protecting the
key migration pathways, especially if these are a target of fi shing, may be needed to
further reduce fi shing mortality in areas surrounding the FSA site. This strategic
approach will also minimize the economic impact on local fi shing communities.
However, if the status of a local fi sh population is unknown or a species is overfi shed, a precautionary approach is needed. Establishing larger protected areas, or
setting zero catch limits for multiple years may be required to help rebuild their
populations. Unfortunately, detailed spatial data for most aggregating species are
not available so more general and conservative approaches will need to be implemented. These may include protecting aggregating species during spawning using
seasonal market closures, or broadly protecting specifi c habitats known to include
spawning aggregations sites (i.e. reef channels, drop offs, promontories) (Chaps. 5
and 10 ) (Sadovy de Mitcheson et al. 2008 ) .
Although the geographical boundaries of highly mobile marine organisms are typically diffi cult to determine (Pittman and McAlpine 2003 ) , mapping the extent of fi sh
spawning migrations and their natural boundaries is important for understanding habitat use and distribution patterns of aggregating species and would address a critical
gap in knowledge for effective implementation of EBM. Because migration distances
and catchment areas for aggregating species may vary depending upon the size of the
insular shelf, detailed tagging and acoustic studies are needed across a broad range of
species and geographical areas to identify movement patterns and habitats that are
important during the reproductive season (i.e. spawning sites and migration pathways). These data should be integrated with bathymetric features and oceanographic
patterns surrounding spawning aggregation sites (Colin et al. 2003 ; Heyman et al.
2007 ) to better understand the importance of adult migration, larval retention mechanisms and dispersal patterns on the connectivity of reef fi sh populations (Eggleston
1995 ; Colin et al. 1997 ; Dahlgren and Eggleston 2001 ; Whaylen et al. 2006 ; Nemeth
et al. 2008 ; Cherubin et al. 2011 ) . Moreover, incorporating these empirical data into
population models can help to predict the resilience of reef fi sh populations exposed
to increasing fi shing pressure, habitat degradation or climate change, and assist in
future management decisions and MPA planning (Botsford et al. 2009 ) .
The need for more detailed information on, and effective management of, spawning
aggregations is without question. Worldwide nearly half of all known FSA’s are in
decline or have disappeared and an equal number of aggregations have no information
available as to their status (Sadovy de Mitcheson et al. 2008 ) . Many aggregating
species play an unknown, yet potentially important, role in ecosystem function.
For example, the Nassau grouper was a major commercial species throughout the
2 Ecosystem Aspects of Species That Aggregate to Spawn
from habitat damage, and the direct and indirect impacts of fi shing activities is critical
for the long-term sustainability of spawning aggregations.
How these spatially distinct components are incorporated into management plans
will depend upon management objectives, priorities and capabilities. For example,
for a species whose population is being fi shed sustainably (either because fi shing
effort is low or the fi shery is well-managed), protecting the core spawning site and
courtship arena during the spawning season may be adequate. For species or populations that are heavily fi shed, incorporating the staging area into a no-fi shing zone
may be the most appropriate course of action. If data are available, protecting the
key migration pathways, especially if these are a target of fi shing, may be needed to
further reduce fi shing mortality in areas surrounding the FSA site. This strategic
approach will also minimize the economic impact on local fi shing communities.
However, if the status of a local fi sh population is unknown or a species is overfi shed, a precautionary approach is needed. Establishing larger protected areas, or
setting zero catch limits for multiple years may be required to help rebuild their
populations. Unfortunately, detailed spatial data for most aggregating species are
not available so more general and conservative approaches will need to be implemented. These may include protecting aggregating species during spawning using
seasonal market closures, or broadly protecting specifi c habitats known to include
spawning aggregations sites (i.e. reef channels, drop offs, promontories) (Chaps. 5
and 10 ) (Sadovy de Mitcheson et al. 2008 ) .
Although the geographical boundaries of highly mobile marine organisms are typically diffi cult to determine (Pittman and McAlpine 2003 ) , mapping the extent of fi sh
spawning migrations and their natural boundaries is important for understanding habitat use and distribution patterns of aggregating species and would address a critical
gap in knowledge for effective implementation of EBM. Because migration distances
and catchment areas for aggregating species may vary depending upon the size of the
insular shelf, detailed tagging and acoustic studies are needed across a broad range of
species and geographical areas to identify movement patterns and habitats that are
important during the reproductive season (i.e. spawning sites and migration pathways). These data should be integrated with bathymetric features and oceanographic
patterns surrounding spawning aggregation sites (Colin et al. 2003 ; Heyman et al.
2007 ) to better understand the importance of adult migration, larval retention mechanisms and dispersal patterns on the connectivity of reef fi sh populations (Eggleston
1995 ; Colin et al. 1997 ; Dahlgren and Eggleston 2001 ; Whaylen et al. 2006 ; Nemeth
et al. 2008 ; Cherubin et al. 2011 ) . Moreover, incorporating these empirical data into
population models can help to predict the resilience of reef fi sh populations exposed
to increasing fi shing pressure, habitat degradation or climate change, and assist in
future management decisions and MPA planning (Botsford et al. 2009 ) .
The need for more detailed information on, and effective management of, spawning
aggregations is without question. Worldwide nearly half of all known FSA’s are in
decline or have disappeared and an equal number of aggregations have no information
available as to their status (Sadovy de Mitcheson et al. 2008 ) . Many aggregating
species play an unknown, yet potentially important, role in ecosystem function.
For example, the Nassau grouper was a major commercial species throughout the