421
12 Species Case Studies
James Locascio (unpublished data) verifi ed this by collecting fertilized goliath
grouper eggs (DNA verifi cation by Matthew Craig, University of Puerto Rico) on
two spawning aggregations and also collected eggs on all phases of the moon off
central east Florida.
12.4.4 Conservation and Management
All of the information on the status of goliath grouper populations comes from a
combination of local and scientifi c knowledge. It is primarily the former that
revealed how scarce goliath grouper populations had become throughout their
range, with many fi shers noting that large aggregations and large individuals had all
but disappeared from many sites, leaving only remnants of historical sites and only
local knowledge of what had been present before (details below). This has gone on
for so long that the historical baseline has shifted signifi cantly as local knowledge
erodes and older fi shers are replaced by younger ones without similar experiences.
This leaves photographic and newspaper records to provide the important historic
perspective. McClenachan ( 2009 ) used these to great effect to show the dramatic
declines occurring in the south Florida goliath grouper population since the early
part of the twentieth century.
The decline of the Atlantic goliath grouper populations can be attributed to a
combination of overfi shing and loss of nursery habitat. Overfi shing by commercial
and recreational fi shers occurred rapidly because the characteristics of these fi sh
– their longevity, aggregating behaviour, and sedentary nature – combined with
technological advances in positioning gear over the last 30 years – made them
particularly vulnerable to fi shing pressure (Ferreira and Maida 1995 ; Sadovy and
Eklund 1999 ; Coleman et al. 2000 ) . Many aggregations have evidently disappeared
throughout the western Atlantic (Sadovy and Eklund 1999 ; Graham et al. 2008 ). In
South Brazil, historical aggregations once having at least 60 individuals have
dwindled to only a dozen fi sh, according to local knowledge (Gerhardinger et al.
2006 ) . The coupled effects of overfi shing and the loss of mangrove habitat extent
and quality have probably accelerated population declines. Much of the habitat
loss is due primarily to direct destruction from aquacultural, agricultural, and urban
development, and from mosquito control impoundments, while water quality
declined as a result of upland agricultural and urban runoff, and fresh water diversions (discussed in Koenig et al. 2007 ) .
These population declines have resulted in fi shery closures in both Brazil and the
United States, and led the IUCN to list goliath grouper on the Red List as critically
endangered, a category reserved for the most threatened and impacted species
(IUCN 2010 ) . Despite these closures, a signifi cant bottleneck to complete recovery
and sustainability continues without similar protection for mangrove habitat (Koenig
et al. 2007 ) .
There is a bright spot in this sea of bad news for goliath grouper. Indeed, fi shing
mortality in the United States has declined (by 50–90%) as a result of the fi shery
closure (Kingsley 2004 ; Porch et al. 2006 ) and the population in the southeastern
12 Species Case Studies
James Locascio (unpublished data) verifi ed this by collecting fertilized goliath
grouper eggs (DNA verifi cation by Matthew Craig, University of Puerto Rico) on
two spawning aggregations and also collected eggs on all phases of the moon off
central east Florida.
12.4.4 Conservation and Management
All of the information on the status of goliath grouper populations comes from a
combination of local and scientifi c knowledge. It is primarily the former that
revealed how scarce goliath grouper populations had become throughout their
range, with many fi shers noting that large aggregations and large individuals had all
but disappeared from many sites, leaving only remnants of historical sites and only
local knowledge of what had been present before (details below). This has gone on
for so long that the historical baseline has shifted signifi cantly as local knowledge
erodes and older fi shers are replaced by younger ones without similar experiences.
This leaves photographic and newspaper records to provide the important historic
perspective. McClenachan ( 2009 ) used these to great effect to show the dramatic
declines occurring in the south Florida goliath grouper population since the early
part of the twentieth century.
The decline of the Atlantic goliath grouper populations can be attributed to a
combination of overfi shing and loss of nursery habitat. Overfi shing by commercial
and recreational fi shers occurred rapidly because the characteristics of these fi sh
– their longevity, aggregating behaviour, and sedentary nature – combined with
technological advances in positioning gear over the last 30 years – made them
particularly vulnerable to fi shing pressure (Ferreira and Maida 1995 ; Sadovy and
Eklund 1999 ; Coleman et al. 2000 ) . Many aggregations have evidently disappeared
throughout the western Atlantic (Sadovy and Eklund 1999 ; Graham et al. 2008 ). In
South Brazil, historical aggregations once having at least 60 individuals have
dwindled to only a dozen fi sh, according to local knowledge (Gerhardinger et al.
2006 ) . The coupled effects of overfi shing and the loss of mangrove habitat extent
and quality have probably accelerated population declines. Much of the habitat
loss is due primarily to direct destruction from aquacultural, agricultural, and urban
development, and from mosquito control impoundments, while water quality
declined as a result of upland agricultural and urban runoff, and fresh water diversions (discussed in Koenig et al. 2007 ) .
These population declines have resulted in fi shery closures in both Brazil and the
United States, and led the IUCN to list goliath grouper on the Red List as critically
endangered, a category reserved for the most threatened and impacted species
(IUCN 2010 ) . Despite these closures, a signifi cant bottleneck to complete recovery
and sustainability continues without similar protection for mangrove habitat (Koenig
et al. 2007 ) .
There is a bright spot in this sea of bad news for goliath grouper. Indeed, fi shing
mortality in the United States has declined (by 50–90%) as a result of the fi shery
closure (Kingsley 2004 ; Porch et al. 2006 ) and the population in the southeastern