226
Y. Sadovy de Mitcheson and B. Erisman
are given in more detail. We examine the socioeconomic importance, costs and
benefi ts of exploiting reef fi sh aggregations for both extractive and non-extractive
(e.g. tourism and reproductive output) purposes. Against this background, we provide recommendations and guidance for future research, education, management
and conservation for aggregating species. We use the defi nition of spawning aggregation (transient and resident) as elaborated in Chap. 1 .
Fishes that aggregate to spawn form an important component of marine fi sheries
and ecosystems globally. While most such species are caught throughout the year, it
is commonly during the spawning season that landings volumes are greatest. Such
aggregations naturally offer a welcome opportunity for large catches and easy earnings often representing a seasonal bounty to be shared by whole communities.
They are targeted for recreational and tourist fi shing charters, or may be important
for cultural events. While most aggregations are exploited for fi sh fl esh, for some
species the more valuable target might be ripe gonads or swimbladders (Fig. 8.1 ).
In some species the millions of young produced briefl y each year by the concentrated
spawning of hundreds to thousands of assembled adults support capture-based
aquaculture (CBA) for which large numbers of newly settling or settled juveniles
are collected en masse and grown out in captivity prior to sale. For these species,
aggregations are the only known time that reproduction occurs and are thus important
for maintaining their populations and the fi sheries these support.
Unfortunately, many fi shes that form spawning aggregations have undergone
marked declines in their fi sheries and these reproductive events are increasingly
targeted (Sect. 8.2 ). Numerous documented examples, ranging from reefs to estuarine environments (Table 8.1 ), to the pelagic realm and deepwater seamounts,
demonstrate unequivocally that aggregations can be substantially reduced by excess
fi shing effort over just a few spawning seasons leading to collapse of the fi sheries
they sustain, with important biological, social and economic implications.
Despite widespread declines globally, spawning aggregations of most species
that form them are typically unmanaged. Among key unanswered questions that
may account for such lack of attention, are (1) whether aggregations themselves
need to be a focus of management as opposed to applying more conventional management (such as annual quotas or gear controls) to the fi sh populations of interest
(Chap. 11 ); (2) whether reduced or extirpated aggregation sites can recover following management intervention and how long might be needed for recovery; and (3)
the importance of healthy aggregations to reproduction, and hence the implications
of aggregation declines and losses for harvested species. The strong appeal of aggregations as targets for fi shing, their importance in many seasonal fi sheries, the apparent abundance when aggregation catches are witnessed, and general lack of data
on catches, together with the three above noted factors, make their management
particularly challenging.
The preservation of suffi cient spawning (reproductive) biomass in exploited populations is a core guiding principle in fi sheries science for ensuring sustainable
resource use. However, how this principle is best applied to aggregating species is
unclear for two reasons. First, the extent to which declining trends in fi sheries of
aggregating species are due to exploitation of aggregations per se is uncertain: many
Y. Sadovy de Mitcheson and B. Erisman
are given in more detail. We examine the socioeconomic importance, costs and
benefi ts of exploiting reef fi sh aggregations for both extractive and non-extractive
(e.g. tourism and reproductive output) purposes. Against this background, we provide recommendations and guidance for future research, education, management
and conservation for aggregating species. We use the defi nition of spawning aggregation (transient and resident) as elaborated in Chap. 1 .
Fishes that aggregate to spawn form an important component of marine fi sheries
and ecosystems globally. While most such species are caught throughout the year, it
is commonly during the spawning season that landings volumes are greatest. Such
aggregations naturally offer a welcome opportunity for large catches and easy earnings often representing a seasonal bounty to be shared by whole communities.
They are targeted for recreational and tourist fi shing charters, or may be important
for cultural events. While most aggregations are exploited for fi sh fl esh, for some
species the more valuable target might be ripe gonads or swimbladders (Fig. 8.1 ).
In some species the millions of young produced briefl y each year by the concentrated
spawning of hundreds to thousands of assembled adults support capture-based
aquaculture (CBA) for which large numbers of newly settling or settled juveniles
are collected en masse and grown out in captivity prior to sale. For these species,
aggregations are the only known time that reproduction occurs and are thus important
for maintaining their populations and the fi sheries these support.
Unfortunately, many fi shes that form spawning aggregations have undergone
marked declines in their fi sheries and these reproductive events are increasingly
targeted (Sect. 8.2 ). Numerous documented examples, ranging from reefs to estuarine environments (Table 8.1 ), to the pelagic realm and deepwater seamounts,
demonstrate unequivocally that aggregations can be substantially reduced by excess
fi shing effort over just a few spawning seasons leading to collapse of the fi sheries
they sustain, with important biological, social and economic implications.
Despite widespread declines globally, spawning aggregations of most species
that form them are typically unmanaged. Among key unanswered questions that
may account for such lack of attention, are (1) whether aggregations themselves
need to be a focus of management as opposed to applying more conventional management (such as annual quotas or gear controls) to the fi sh populations of interest
(Chap. 11 ); (2) whether reduced or extirpated aggregation sites can recover following management intervention and how long might be needed for recovery; and (3)
the importance of healthy aggregations to reproduction, and hence the implications
of aggregation declines and losses for harvested species. The strong appeal of aggregations as targets for fi shing, their importance in many seasonal fi sheries, the apparent abundance when aggregation catches are witnessed, and general lack of data
on catches, together with the three above noted factors, make their management
particularly challenging.
The preservation of suffi cient spawning (reproductive) biomass in exploited populations is a core guiding principle in fi sheries science for ensuring sustainable
resource use. However, how this principle is best applied to aggregating species is
unclear for two reasons. First, the extent to which declining trends in fi sheries of
aggregating species are due to exploitation of aggregations per se is uncertain: many