382
M.W. Russell et al.
aggregating species, may need specifi c management such as spatial or seasonal
closures, because they are potentially more vulnerable to overfi shing. This is because
a greater proportion of the adult fi sh population is predictably available to fi shing in
a defi ned area and over a relatively short time period, and there are likely to be fewer
spawning sites compared to resident spawners. For example, for several species of
grouper that aggregate together in Palau, there appears to be only about 10 known
spawning sites in the country (Sadovy 2007 ) , which could be protected. By contrast, resident aggregating species with numerous aggregation sites could be better
managed by seasonal closures and/or other non-aggregation focused measures such
as total allowable catches, species bans or broad spatial closures. Much depends on
the available information regarding the timing and location of spawning, the number
of aggregations, spawning behaviour and local enforcement capacity.
In the Caribbean, many examples of management of aggregating species have
been introduced over the past two decades (Table 11.1 ). These examples demonstrate
the highly variable combinations of management that can be adopted, with many
involving multiple management measures and most focusing on transient aggregators. For example, in Bermuda, seasonal aggregation site closures were introduced,
followed later by possession limits implemented during the spawning season to
reduce the impact of potential poaching at aggregation sites during the closed season
and to aid enforcement of the seasonal closure. For the Nassau grouper in Belize,
aggregation protection proved a challenge and so a minimum size was also introduced to strengthen the management of reproductive capacity for this species (Janet
Gibson personal communication 2010). In Cuba, more and more measures were progressively introduced as the fi shery continued to decline (Claro et al. 2009 ) .
To help determine appropriate management options, we provide general guidance
that can be used for both commercial and subsistence fi sheries, although each aggregation or aggregating species needs to be evaluated on a case-by-case basis as many
different biological, ecological and socio-economic factors can vary considerably.
For low level subsistence fi sheries, precautionary measures are warranted, involving
effort monitoring and possibly limiting effort because even subsistence fi sheries can
deplete an aggregation (Fig. 11.2 ).
If the aggregation sites or timings are known or partly known, the following are
options for aggregation management that can be considered alone or in combination.
1. Short - term site closure of aggregation site . The aggregation site is closed for
the duration of the spawning season, but fi shing for this species is permitted
outside the aggregation.
2. Seasonal closure of fi shery . The fi shery is closed for the spawning season with
no catch permitted, and the aggregation site is not specifi cally protected.
3. Short - term aggregation site and time closure for species . Protect the aggregation
site, and the species from being fi shed anywhere during its spawning season.
4. Fully - protected area . The managed species is protected from fi shing year-round
in a designated MPA, but may be fi shed outside of the MPA at any time. MPAs
should be designed to include the entire aggregation sites and, if applicable,
migration routes.
M.W. Russell et al.
aggregating species, may need specifi c management such as spatial or seasonal
closures, because they are potentially more vulnerable to overfi shing. This is because
a greater proportion of the adult fi sh population is predictably available to fi shing in
a defi ned area and over a relatively short time period, and there are likely to be fewer
spawning sites compared to resident spawners. For example, for several species of
grouper that aggregate together in Palau, there appears to be only about 10 known
spawning sites in the country (Sadovy 2007 ) , which could be protected. By contrast, resident aggregating species with numerous aggregation sites could be better
managed by seasonal closures and/or other non-aggregation focused measures such
as total allowable catches, species bans or broad spatial closures. Much depends on
the available information regarding the timing and location of spawning, the number
of aggregations, spawning behaviour and local enforcement capacity.
In the Caribbean, many examples of management of aggregating species have
been introduced over the past two decades (Table 11.1 ). These examples demonstrate
the highly variable combinations of management that can be adopted, with many
involving multiple management measures and most focusing on transient aggregators. For example, in Bermuda, seasonal aggregation site closures were introduced,
followed later by possession limits implemented during the spawning season to
reduce the impact of potential poaching at aggregation sites during the closed season
and to aid enforcement of the seasonal closure. For the Nassau grouper in Belize,
aggregation protection proved a challenge and so a minimum size was also introduced to strengthen the management of reproductive capacity for this species (Janet
Gibson personal communication 2010). In Cuba, more and more measures were progressively introduced as the fi shery continued to decline (Claro et al. 2009 ) .
To help determine appropriate management options, we provide general guidance
that can be used for both commercial and subsistence fi sheries, although each aggregation or aggregating species needs to be evaluated on a case-by-case basis as many
different biological, ecological and socio-economic factors can vary considerably.
For low level subsistence fi sheries, precautionary measures are warranted, involving
effort monitoring and possibly limiting effort because even subsistence fi sheries can
deplete an aggregation (Fig. 11.2 ).
If the aggregation sites or timings are known or partly known, the following are
options for aggregation management that can be considered alone or in combination.
1. Short - term site closure of aggregation site . The aggregation site is closed for
the duration of the spawning season, but fi shing for this species is permitted
outside the aggregation.
2. Seasonal closure of fi shery . The fi shery is closed for the spawning season with
no catch permitted, and the aggregation site is not specifi cally protected.
3. Short - term aggregation site and time closure for species . Protect the aggregation
site, and the species from being fi shed anywhere during its spawning season.
4. Fully - protected area . The managed species is protected from fi shing year-round
in a designated MPA, but may be fi shed outside of the MPA at any time. MPAs
should be designed to include the entire aggregation sites and, if applicable,
migration routes.