439
12 Species Case Studies
hatchery-reared Nassau grouper, the number of tagged fi sh declined over a 9-month
period after release in the US Virgin Islands. Based on the study and its review of
available information, Nassau grouper stock enhancement was concluded only to be
an option when simpler management methods for attaining wild stock recovery
have failed (Roberts et al. 1995 ) .
12.6.6 Gaps in Knowledge
Despite the fact that the Nassau grouper is one of the best-studied large-bodied reef
fi sh in the Caribbean, we still have substantial knowledge gaps that need to be fi lled
to improve management and ensure the long term persistence of this species. In
particular, a better understanding of population structure, the catchment areas for
aggregations (i.e. how far adults travel to reach specifi c aggregation sites), site fi delity and minimum viable spawning aggregation size is needed on the adult spawning
side. Traditional measures of population productivity need to be determined in order
to determine what reasonable exploitation levels might be. Such determinants of
productivity would of course need to be coupled with effective management measures to sustain viable populations and rebuild depleted ones. Larval dispersal distances, source-sink dynamics, and the frequency of strong year classes are important
aspects of this work.
12.7 Gag Grouper – Mycteroperca microlepis
Christopher C. Koenig and Felicia C. Coleman
Department of Biological Science, Florida State University Coastal and Marine
Laboratory , 3618 Coastal Highway, St. Teresa , FL , 32358 , USA
e-mail: koenig@bio.fsu.edu; coleman@bio.fsu.edu
12.7.1 General
The gag, Mycteroperca microlepis (Goode and Bean 1879) (Family Serranidae), is
a large, relatively slender-bodied grouper with dark vermiculate markings on the
body. Geographic range extends throughout the warm-temperate and sub-tropical
waters of the western Atlantic. They occur primarily from North Carolina to the
Yucatan Peninsula, Mexico, and are very abundant on the West Florida Shelf. This
species is rare in Bermuda, recorded only once in Cuba, and reported from eastern
Brazil (Heemstra and Randall 1993 ; Heemstra et al. 2002 ) . Males are sometimes
called “blackbellies” or “charcoal bellies” because of the presence of dark blotchy
colorations on the belly and ventral sides below the pectoral fi ns (Heemstra et al.
2002 ) (Fig. 12.14 ).
12 Species Case Studies
hatchery-reared Nassau grouper, the number of tagged fi sh declined over a 9-month
period after release in the US Virgin Islands. Based on the study and its review of
available information, Nassau grouper stock enhancement was concluded only to be
an option when simpler management methods for attaining wild stock recovery
have failed (Roberts et al. 1995 ) .
12.6.6 Gaps in Knowledge
Despite the fact that the Nassau grouper is one of the best-studied large-bodied reef
fi sh in the Caribbean, we still have substantial knowledge gaps that need to be fi lled
to improve management and ensure the long term persistence of this species. In
particular, a better understanding of population structure, the catchment areas for
aggregations (i.e. how far adults travel to reach specifi c aggregation sites), site fi delity and minimum viable spawning aggregation size is needed on the adult spawning
side. Traditional measures of population productivity need to be determined in order
to determine what reasonable exploitation levels might be. Such determinants of
productivity would of course need to be coupled with effective management measures to sustain viable populations and rebuild depleted ones. Larval dispersal distances, source-sink dynamics, and the frequency of strong year classes are important
aspects of this work.
12.7 Gag Grouper – Mycteroperca microlepis
Christopher C. Koenig and Felicia C. Coleman
Department of Biological Science, Florida State University Coastal and Marine
Laboratory , 3618 Coastal Highway, St. Teresa , FL , 32358 , USA
e-mail: koenig@bio.fsu.edu; coleman@bio.fsu.edu
12.7.1 General
The gag, Mycteroperca microlepis (Goode and Bean 1879) (Family Serranidae), is
a large, relatively slender-bodied grouper with dark vermiculate markings on the
body. Geographic range extends throughout the warm-temperate and sub-tropical
waters of the western Atlantic. They occur primarily from North Carolina to the
Yucatan Peninsula, Mexico, and are very abundant on the West Florida Shelf. This
species is rare in Bermuda, recorded only once in Cuba, and reported from eastern
Brazil (Heemstra and Randall 1993 ; Heemstra et al. 2002 ) . Males are sometimes
called “blackbellies” or “charcoal bellies” because of the presence of dark blotchy
colorations on the belly and ventral sides below the pectoral fi ns (Heemstra et al.
2002 ) (Fig. 12.14 ).