455
12 Species Case Studies
Spawning aggregations in this species have been analysed with respect to timing,
size, location and distance travelled to sites (Samoilys 1997 ; Zeller 1998 ) . A summary of these features illustrates the differences between large aggregate-spawning
groupers in the tropical Atlantic as opposed to the western Pacifi c. The sizes of
aggregations of the leopard coralgrouper were relatively small with a maximum of
128 fi sh (Samoilys 1997 ) but with much lower numbers in many aggregations.
Zeller ( 1998 ) recorded a mean distance of 912 m for movement between P. leopardus home ranges and aggregation sites recorded at Lizard Island. This study concluded that most instances of aggregate spawning occurred on the reef on which the
individual was resident. Both authors expressed concern as to the longer term continuity of these aggregations in the face of fi shing pressure which prompts questions
with respect to their small size. Are small aggregations in this species a consequence of fi shing pressure? Recent observations by Alex Vail (Lizard Island
Research Station) on spawning by P. leopardus at a site recorded by Zeller ( 1998 )
(Site BR1) helped clarify these issues.
During the 15 years elapsed since Zeller’s observation (Zeller 1998 ) , a similar
sized aggregation was recorded at the same site spawning at dusk during the new
moon phase. Further south, an aggregation on Scott Reef off Cairns has persisted for
20 years (1989–2009) with an average of 109 (range: 47–345) fi sh at the site which
has not declined (Samoilys, Roelofs, Russell and Squire unpublished data). Detailed
population abundance surveys and tagging of P. leopardus in a 6.5km
2 area around
a neighbouring aggregation site at Elford Reef show that the site draws fi sh from a
catchment area of 1.5km
2 with an estimated population of 3,169 adult fi sh, moving
up to 1,200m to the site. Tagging, visual observations and histology suggest a maximum of only 600 of these 3,000 adult fi sh use the aggregation site to spawn (Samoilys
2000). It is concluded that numerous small spawning aggregations of a resident
nature are a consistent feature of the reproductive biology of this abundant western
Pacifi c serranid, but aggregation-spawning is only one mechanism, with a large
number of individuals (>80%) spawning in pairs or small groups..
Small aggregations of the species have also been reported through fi sher interviews in the Solomon Islands, Papua New Guinea, Fiji, Malaysia, Philippines,
Indonesia and Fiji; very large aggregations of this species have nowhere been
reported ( www.SCRFA.org-country reports; Yvonne Sadovy unpublished data).
12.9.4 Conservation and Management Action and Concerns
Conservation and management action is largely limited to Australia where the
commercial Queensland fi shery is limited entry, licensed, with gear restrictions,
quotas and a minimum size limit of 38 cm total length (TL), managed through the
Department of Primary Industries and Fisheries (DPI&F) regulations ( Fisheries
(Coral Reef Fin Fish Fishery) Management Plan 2003) . The size limit prevents
fi shing of the fi rst three age classes, representing both the fastest growth period as
well as when females start reproducing (Ferreira 1995 ) , generally considered a
12 Species Case Studies
Spawning aggregations in this species have been analysed with respect to timing,
size, location and distance travelled to sites (Samoilys 1997 ; Zeller 1998 ) . A summary of these features illustrates the differences between large aggregate-spawning
groupers in the tropical Atlantic as opposed to the western Pacifi c. The sizes of
aggregations of the leopard coralgrouper were relatively small with a maximum of
128 fi sh (Samoilys 1997 ) but with much lower numbers in many aggregations.
Zeller ( 1998 ) recorded a mean distance of 912 m for movement between P. leopardus home ranges and aggregation sites recorded at Lizard Island. This study concluded that most instances of aggregate spawning occurred on the reef on which the
individual was resident. Both authors expressed concern as to the longer term continuity of these aggregations in the face of fi shing pressure which prompts questions
with respect to their small size. Are small aggregations in this species a consequence of fi shing pressure? Recent observations by Alex Vail (Lizard Island
Research Station) on spawning by P. leopardus at a site recorded by Zeller ( 1998 )
(Site BR1) helped clarify these issues.
During the 15 years elapsed since Zeller’s observation (Zeller 1998 ) , a similar
sized aggregation was recorded at the same site spawning at dusk during the new
moon phase. Further south, an aggregation on Scott Reef off Cairns has persisted for
20 years (1989–2009) with an average of 109 (range: 47–345) fi sh at the site which
has not declined (Samoilys, Roelofs, Russell and Squire unpublished data). Detailed
population abundance surveys and tagging of P. leopardus in a 6.5km
2 area around
a neighbouring aggregation site at Elford Reef show that the site draws fi sh from a
catchment area of 1.5km
2 with an estimated population of 3,169 adult fi sh, moving
up to 1,200m to the site. Tagging, visual observations and histology suggest a maximum of only 600 of these 3,000 adult fi sh use the aggregation site to spawn (Samoilys
2000). It is concluded that numerous small spawning aggregations of a resident
nature are a consistent feature of the reproductive biology of this abundant western
Pacifi c serranid, but aggregation-spawning is only one mechanism, with a large
number of individuals (>80%) spawning in pairs or small groups..
Small aggregations of the species have also been reported through fi sher interviews in the Solomon Islands, Papua New Guinea, Fiji, Malaysia, Philippines,
Indonesia and Fiji; very large aggregations of this species have nowhere been
reported ( www.SCRFA.org-country reports; Yvonne Sadovy unpublished data).
12.9.4 Conservation and Management Action and Concerns
Conservation and management action is largely limited to Australia where the
commercial Queensland fi shery is limited entry, licensed, with gear restrictions,
quotas and a minimum size limit of 38 cm total length (TL), managed through the
Department of Primary Industries and Fisheries (DPI&F) regulations ( Fisheries
(Coral Reef Fin Fish Fishery) Management Plan 2003) . The size limit prevents
fi shing of the fi rst three age classes, representing both the fastest growth period as
well as when females start reproducing (Ferreira 1995 ) , generally considered a