240
Y. Sadovy de Mitcheson and B. Erisman
their exploitation. Specifi cally, we need to know: (1) the degree to which a fi shery
depends on aggregation catches and how the increased ease of capture at such times
can promote overfi shing; (2) the extent to which the subtleties of mating behaviour
and other reproductive parameters are or might be affected by fi shing activities on
aggregations, (3) the social and economic challenges and implications of managing,
versus losing, aggregations, and (4) the contribution of healthy aggregations to the
overall productivity of the fi shery.
Determining the appropriate management approaches for aggregating species is
important because of the obvious appeal and attraction of fi shing them, especially if
this is a traditional or highly lucrative activity. The historical absence of controls on
aggregation-fi shing or collective experience of marked declines, however, makes their
management uniquely challenging, as we shall illustrate. The need for steady market
supplies may make a seasonal break in fi shing, as could occur with management,
unpopular. Combine these factors with the prevailing lack of information on the specifi c biological and economic impacts of fi shing on aggregations per se and it becomes
easier to appreciate why so few are adequately managed and protected. Even conservation-focused measures, such as marine protected areas, do not routinely consider
aggregation protection except when species are already threatened with extinction and
thus merit conservative management. It has also become clear that public perspectives
and education about aggregations require considerably more attention.
8.2 Types of Extractive Exploitation
Many fi sh species taken in coastal fi sheries of the tropics and subtropics, whether
for subsistence, recreational, cultural or commercial purposes, aggregate at predictable times and places to spawn. Not all aggregating species are fi shed at their spawning aggregations, however. Some, like certain rabbitfi shes (Siganidae), mullets
(Mugilidae) and bonefi shes (Albulidae) are specifi cally targeted during spawning
migrations. Intensive fi sheries for CBA on the massive larval settlement pulses of
certain mullet, grouper (Serranidae), milkfi sh (Channidae) or rabbitfi sh species are
partly possible due to aggregation-spawning.
This section provides a general overview of the subsistence, recreational and commercial uses of spawning aggregations with indications of management (covered
more in Chap. 11 ) and landings trends. While some smaller aggregating species, like
the blacktail snapper, Lutjanus fulvus (Chap. 12.10 ), are not specifi cally targeted (and
therefore do not currently represent management challenges) we particularly focus
on those species targeted heavily at or travelling to their aggregations, rather than on
aggregating species in general, because: (1) aggregations or pre-spawning migrations
of ripe fi sh are particularly vulnerable to overfi shing and often make up a signifi cant
proportion of the annual catch; (2) aggregations or pre-spawning migrations are
increasingly a specifi c target for fi shing and can be very valuable; and (3) managing
aggregation-fi shing and conserving aggregations pose a unique challenge, both for
conventional management as well as for marine protected area designation.
Y. Sadovy de Mitcheson and B. Erisman
their exploitation. Specifi cally, we need to know: (1) the degree to which a fi shery
depends on aggregation catches and how the increased ease of capture at such times
can promote overfi shing; (2) the extent to which the subtleties of mating behaviour
and other reproductive parameters are or might be affected by fi shing activities on
aggregations, (3) the social and economic challenges and implications of managing,
versus losing, aggregations, and (4) the contribution of healthy aggregations to the
overall productivity of the fi shery.
Determining the appropriate management approaches for aggregating species is
important because of the obvious appeal and attraction of fi shing them, especially if
this is a traditional or highly lucrative activity. The historical absence of controls on
aggregation-fi shing or collective experience of marked declines, however, makes their
management uniquely challenging, as we shall illustrate. The need for steady market
supplies may make a seasonal break in fi shing, as could occur with management,
unpopular. Combine these factors with the prevailing lack of information on the specifi c biological and economic impacts of fi shing on aggregations per se and it becomes
easier to appreciate why so few are adequately managed and protected. Even conservation-focused measures, such as marine protected areas, do not routinely consider
aggregation protection except when species are already threatened with extinction and
thus merit conservative management. It has also become clear that public perspectives
and education about aggregations require considerably more attention.
8.2 Types of Extractive Exploitation
Many fi sh species taken in coastal fi sheries of the tropics and subtropics, whether
for subsistence, recreational, cultural or commercial purposes, aggregate at predictable times and places to spawn. Not all aggregating species are fi shed at their spawning aggregations, however. Some, like certain rabbitfi shes (Siganidae), mullets
(Mugilidae) and bonefi shes (Albulidae) are specifi cally targeted during spawning
migrations. Intensive fi sheries for CBA on the massive larval settlement pulses of
certain mullet, grouper (Serranidae), milkfi sh (Channidae) or rabbitfi sh species are
partly possible due to aggregation-spawning.
This section provides a general overview of the subsistence, recreational and commercial uses of spawning aggregations with indications of management (covered
more in Chap. 11 ) and landings trends. While some smaller aggregating species, like
the blacktail snapper, Lutjanus fulvus (Chap. 12.10 ), are not specifi cally targeted (and
therefore do not currently represent management challenges) we particularly focus
on those species targeted heavily at or travelling to their aggregations, rather than on
aggregating species in general, because: (1) aggregations or pre-spawning migrations
of ripe fi sh are particularly vulnerable to overfi shing and often make up a signifi cant
proportion of the annual catch; (2) aggregations or pre-spawning migrations are
increasingly a specifi c target for fi shing and can be very valuable; and (3) managing
aggregation-fi shing and conserving aggregations pose a unique challenge, both for
conventional management as well as for marine protected area designation.