Yellowedge grouper  (Hyporthodus flavolimbatus)

The yellowedge grouper is classified as Vulnerable (VU) on the IUCN Red List (1).

Similar in appearance to the snowy grouper (Epinephelus niveatus), the yellowedge grouper (Hyporthodus flavolimbatus) can be distinguished by its bright yellow eyes and fin margins, accounting for the common name ‘yellowedge’ (4). The rest of its body is a greyish-brown, with white tips on the dorsal and pectoral fins (3). Juveniles have pearly coloured spots, broad yellow margins on the fins and a bright blue line near the corner of the eye, which can also be faintly seen in some adults (3). Adults up to 80 centimetres in length also display pearly spots, but interestingly these disappear as soon as the fish is removed from the water (4).

The yellowedge grouper is found in the Western Atlantic, off the coast of North and South America, from North Carolina down to southern Brazil (3).

The yellowedge grouper is a deep water fish (2), with an individual once reported at a depth of 390 meters (5). However, it is more commonly found between depths of 125 and 300 metres, while juveniles show a preference for shallower waters of 35 to 125 metres (4) (5).

Although most grouper species prefer reef and rocky habitats, the yellowedge grouper is found in a variety of habitats (4) (6), including areas with a sand or mud bottom. In areas with soft bottoms this species is often seen in or near trenches or burrow-like excavations (1). These burrows are usually in one of three forms: vertical, crater or trench (7). The vertical and crater burrows are thought to be precursors to the trench burrow, which can be seven or eight metres long, and up to three metres wide (6).

The yellowedge grouper is a carnivorous species (8), feeding mainly on crabs and other invertebrates, as well as some fish (3).

A solitary species (1), the yellowedge grouper is a protogynous hermaphrodite, beginning life as a female and becoming male as it increases in age and size (4). It is thought that around half of all females transform into males by the time they reach 81 centimetres in length (1).

Sexual reproduction appears to peak between May and September (2), and the larvae of the yellowedge grouper are indistinguishable from those of the snowy grouper (Epinephelus niveatus), meaning that little is known about the very beginning of its lifecycle (4). It has recently been discovered that the yellowedge grouper may possibly have a lifespan of up to 80 years (5).

The major threat to the yellowedge grouper is fishing (5), as it is targeted by both commercial longliners and recreational anglers, which is the cause of current population declines (2).

During the 1980s, 13 metric tons of snowy and yellowedge groupers could be brought back from 10 day fishing trips (2). It is currently the third most abundant grouper harvested from the Gulf of Mexico, with around $2.2 million worth landed each year (5).

Grouper species are offered some protection in the waters around the United States, with recreational fishermen subjected to a bag limit of five groupers per person per day. Limits have also been placed on commercial fishing, with trawls, traps and bottom long lines prohibited in some coastal areas of Florida, and limits placed on the number of vessels allowed to fish in the area (1).

For further information on the conservation of groupers see:

• IUCN/SSC Grouper and Wrasse Specialist Group:
  http://www.hku.hk/ecology/GroupersWrasses/iucnsg