420
12 Species Case Studies
of 5–6 years, and 100% mature by the age of 7 years. Females mature by the time
they reach 1,225 mm TL and 6 years of age (Bullock et al. 1992 ) .
The Atlantic goliath grouper is one of the few large groupers that form spawning aggregations on shallow (<50 m) offshore reefs (Coleman and Koenig 2003 ) ,
especially those with high relief rocky ledges, or wrecks and artifi cial reefs with
large holes and caves. Spawning aggregations can consist of up to 100 or more
individuals and are spatially and temporally consistent – that is, spawning occurs
at the same time from year to year, and fi sh exhibit strong inter-annual spawning
site fi delity (Fig. 12.6 ).
Goliath grouper start forming spawning aggregations in the summer that persist
through fall in the northern hemisphere, with perhaps some geographic variation in
timing. Reproductive condition suggests a somewhat contracted spawning period in
the northeastern Caribbean during July and August (Erdman 1976 ) and more protracted spawning in the Gulf of Mexico from June through December (Bullock et al.
1992 ) , whereas acoustic recordings of spawning aggregations suggest that spawning occurs from early August to late October (Mann et al. 2009 ) . The spawning
period at any one site may persist for a few months each year and likely represents
the total annual reproductive output (Sadovy and Eklund 1999 ) .
There is some suggestion of lunar infl uence on the timing of spawning (Colin
1994 ; Hostim-Silva et al. 2005 ; Gerhardinger et al. 2006 ; Mann et al. 2009 ) . While
Colin ( 1994 ) , Gerhardinger et al. ( 2006 ) , and Hostim-Silva et al. ( 2005 ) assumed
spawning periodicity was related to full moons, based on reproductive condition,
Mann et al. ( 2009 ) suggest that spawning takes place on moonless nights, based on
results from active and passive acoustic tracking [the species-specifi c low-frequency
(50–100 Hz) pulsed sounds produced at night exhibit a lunar periodicity that is
apparently associated with reproductive behaviour, Mann et al. 2008 ] . CKK and
Fig. 12.6 Adult goliath grouper in a small spawning aggregation in Florida (Photo: © Walt Stearns)
12 Species Case Studies
of 5–6 years, and 100% mature by the age of 7 years. Females mature by the time
they reach 1,225 mm TL and 6 years of age (Bullock et al. 1992 ) .
The Atlantic goliath grouper is one of the few large groupers that form spawning aggregations on shallow (<50 m) offshore reefs (Coleman and Koenig 2003 ) ,
especially those with high relief rocky ledges, or wrecks and artifi cial reefs with
large holes and caves. Spawning aggregations can consist of up to 100 or more
individuals and are spatially and temporally consistent – that is, spawning occurs
at the same time from year to year, and fi sh exhibit strong inter-annual spawning
site fi delity (Fig. 12.6 ).
Goliath grouper start forming spawning aggregations in the summer that persist
through fall in the northern hemisphere, with perhaps some geographic variation in
timing. Reproductive condition suggests a somewhat contracted spawning period in
the northeastern Caribbean during July and August (Erdman 1976 ) and more protracted spawning in the Gulf of Mexico from June through December (Bullock et al.
1992 ) , whereas acoustic recordings of spawning aggregations suggest that spawning occurs from early August to late October (Mann et al. 2009 ) . The spawning
period at any one site may persist for a few months each year and likely represents
the total annual reproductive output (Sadovy and Eklund 1999 ) .
There is some suggestion of lunar infl uence on the timing of spawning (Colin
1994 ; Hostim-Silva et al. 2005 ; Gerhardinger et al. 2006 ; Mann et al. 2009 ) . While
Colin ( 1994 ) , Gerhardinger et al. ( 2006 ) , and Hostim-Silva et al. ( 2005 ) assumed
spawning periodicity was related to full moons, based on reproductive condition,
Mann et al. ( 2009 ) suggest that spawning takes place on moonless nights, based on
results from active and passive acoustic tracking [the species-specifi c low-frequency
(50–100 Hz) pulsed sounds produced at night exhibit a lunar periodicity that is
apparently associated with reproductive behaviour, Mann et al. 2008 ] . CKK and
Fig. 12.6 Adult goliath grouper in a small spawning aggregation in Florida (Photo: © Walt Stearns)