Gulf grouper


The Gulf grouper is a species of marine ray-finned fish, a grouper from the subfamily Epinephelinae which is part of the family Serranidae, which also includes the anthias and sea basses. It is endemic to Mexico.

Description

The Gulf grouper has an elongate, robust and compressed body which is no deeper at the origin of the dorsal fin than it as the origin of the anal fin. It standard length is 3.1 to 3.4 times its depth. The preopercle is rounded, lackaing a lobe, and has a finely serrated margin. The dorsal fin contains 11 spines and 16-17 soft rays while the anal fin contains 3 spines and 10-11 soft rays. The caudal fin is straight to concave. The colour of the adults is Adults normally a uniform dark brown or grey, although they have the ability to quickly change colour and to adopt a pattern resembling that of juveniles. In the larger adults, the margin of the pectoral fin is white and the dorsal, anal and caudal fins have a narrow white edge. The juveniles are greyish brown marked with large, dark grey roughly rectangular blotches on the upper part of the body and fins. The maximum published total length for this species is and the maximum published weight is.

Distribution

The Gulf grouper is found in the eastern pacific Ocean where it is endemic to Mexican waters from San Carlos, Baja California Sur south to Mazatlán. It is found throughout the Gulf of California and around the Revillagigedos Islands. It has been recorded as a vagrant off San Diego in the 1940s and 1950s.

Habitat and biology

The Gulf grouper is found over rocky reefs, kelp beds and sea mounts. The adults are normally found at depths between but has been recorded as deep as during the summer months, and even as deep as on reefs. The juveniles are found in shallow rocky reefs and artificial reefs, and also in estuaries, mangroves and bays around the islands and along the northern and central coastlines of the Gulf of California. They have been reported to prey on juvenile hammerhead sharks. The more usual prey is other fish, lobsters and slipper lobsters. It is though that these fish attain sexual maturity at six to seven years when they are around in total length. The adults form

Taxonomy

The Gulf grouper was first formally described as Epinephelus jordani in 1889 by the American academic Oliver Peebles Jenkins and the ichthyologist Barton Warren Evermann with the type locality given as Guaymas in the state of Sonora in western Mexico. The specific name honours the American ichthyologist David Starr Jordan.

Utilisation and threats

The Gulf grouper is considered to be one of the most valuable groupers caught in the Gulf of California by commercial and recreational fisheries. It is thought that overfishing has caused the population has declined by at least 50% over the past 80 years, or so, and so the IUCN have listed it as Endangered.