Sickelfish grouper (Dermatolepis inermis)
|Also known as:||donkey fish, marbled grouper, mutton hamlet, rockhind|
|Synonyms:||Dermatolepis marmoratus, Dermatolepis zanclus, Epinephelus inermis, Serranus inermis|
|Spanish:||Boricua, Cherna Jaspeada, Mero Marmal, Mero Tigre, Viuda|
|Size||Length: up to 90 cm (2)|
The sickelfish grouper is classified as Near Threatened (NT) on the IUCN Red List (1).
A large predatory fish of coral reefs in the western Atlantic, the sickelfish grouper (Dermatolepis inermis) is mottled greyish-brown, with white speckling and small black spots loosely arranged into rings (2). The body is deep and compressed, with large, rounded fins. The head is steep, with the heavily-lipped mouth facing upwards. The front of the dorsal fin has eleven spines, while the front of the anal fin has three. The juvenile sickelfish grouper is black or dark brown and covered with irregular white spots and blotches (3).
The sickelfish grouper is a western Atlantic species with two distinct populations. One population ranges from the mid-eastern coast of the US, eastwards to Bermuda and southwards through the Gulf of Mexico and the Caribbean to Venezuela. The other population occurs from northern to south-eastern Brazil (1).
A reef-dwelling species, the sickelfish grouper is usually found around deep crevices and ledges, down to depths of around 210 metres (1).
Little is known about this rare and secretive species but, like other groupers, it is a carnivore that ambushes its fish and crustacean prey (2) (4).
Similar to other grouper species, the sickelfish grouper is probably solitary, but forms spawning aggregations of hundreds of individuals when breeding (1). During this time, sperm and eggs are synchronously released, with fertilisation occurring in the water (3). The eggs hatch into larvae that drift passively in the ocean currents as part of the zooplankton community, before becoming juveniles and hiding within sea-grass (5). Remarkably, most groupers begin life as females, becoming male after reaching a certain age or length (4).
As a result of overfishing, the adult sickelfish grouper is now a rare species and its populations are declining (1). Due to its rarity, it is not a viable food source and is of little commercial importance to the fishing industry (3). However, it is still at risk from further overfishing, especially in spawning areas where aggregations could become easy prey for fisheries. Juvenile sickelfish groupers are also captured for the aquarium trade (1).
The sickelfish grouper occurs in Marine Protected Areas in some parts of its range. Further surveys are required to determine the location of potential spawning sites so that they can be afforded protection (1).
For more information on conservation in Bermuda:
The Bermuda National Trust:
For more information on fish conservation in the Atlantic Ocean:
Atlantic Coastal Fish Habitat Partnership:
This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
- Anal fin: in fish, an unpaired fin on the under surface of a fish, behind the anus.
- Carnivore: an organism that feeds on flesh. The term can also be used to refer to a mammal in the order Carnivora.
- Crustaceans: diverse group of animals with jointed limbs and a hard chitinous exoskeleton characterised by the possession of two pairs of antennae, one pair of mandibles (mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps and barnacles.
- Dorsal fin: the unpaired fin found on the back of the body of fish, or the raised structure on the back of most cetaceans.
- Fertilisation: the fusion of gametes (male and female reproductive cells) to produce an embryo, which grows into a new individual.
- Larvae: stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
- Spawning: the production or depositing of large quantities of eggs in water.
- Zooplankton: tiny aquatic animals that drift with currents or swim weakly in water.
IUCN Red List (September, 2010)
- McEachran, J.D. and Fechhelm, J.D. (2005) Fishes of the Gulf of Mexico. University of Texas Press, Texas, USA.
Heemstra, P.C. and Randall, J.E. (1993) Groupers of the world (family Serranidae, subfamily Epinephelinae). FAO Species Catalogue, 125(16): 66-67. Available at:
- Goldstein, R.J. (2008) Marine Reef Aquarium Handbook. Barron’s Educational Series, Inc, New York, USA.
Florida Museum of Natural History (October, 2010)