Monday 2 July 2012

Nassau grouper

Nassau grouper

 
Nassau grouper
Conservation status
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Actinopterygii
Order:Perciformes
Family:Serranidae
Genus:Epinephelus
Species:E. striatus
Binomial name
Epinephelus striatus
(Bloch, 1792)
The Nassau grouper (Epinephelus striatus) is one of the large number of Perciform fish in the family Serranidae that are commonly referred to as groupers. It is the most important of the groupers for commercial fishery in the West Indies but has been endangered by overfishing.
The Nassau grouper is a U.S. National Marine Fisheries Service Species of Concern. Species of Concern are those species about which the U.S. Government’s National Oceanic and Atmospheric Administration, National Marine Fisheries Service, has some concerns regarding status and threats, but for which insufficient information is available to indicate a need to list the species under the U.S. Endangered Species Act (ESA).

 

 Species Description

Nassau grouper, Epinephelus striatus, ambushes its prey on Caribbean coral reefs.
The Nassau grouper is a medium to large fish, growing to over a meter in length and up to 25 kilograms in weight. It has a thick body and large mouth, which it uses to "inhale" prey. Its colour varies depending on an indivudual fishes circumstances and environment. In shallow water (up to 60 feet), the grouper is a tawny color, but specimens that live in deeper waters are pinkish or red, or sometimes orange-red color. Superimposed on this base colour are a number of lighter stripes, darker spots, bars and patterns including black spots below and behind the eye, and a forked stripe on the top of head

 Ecology

The Nassau grouper lives in the sea, preferring to be near reefs; it is one of the largest fish to be found around Coral Reefs. It can be found anywhere from the shoreline to nearly water that are up to 100 m deep. The Nassau Grouper lives in the western Atlantic Ocean, from Bermuda, Florida and the Bahamas in the north to southern Brazil, but it is only found in a few places in the Gulf of Mexico, most notably along the coast of Belize.[1] It is a solitary fish, feeding in the daytime, mainly on other fish and small crustaceans like crabs and small lobsters. It spawns in December and January, always around the time of the full moon, and always in the same locations. By the light of the full moon, huge numbers of the grouper cluster together to mate in mass spawning. One reason the Nassau Grouper fisheries are so depleted is that its huge spawning groups make easy targets for fishermen, who scoop up large numbers of reproducing fish, who then can obviously not reproduce. Many other grouper and snapper species are in trouble of becoming endangered or extinct for the same reason.[2]

 Conservation

The Nassau grouper is fished both commercially and for sport; it is less shy than other groupers, and is readily approached by scuba divers. However, its numbers have been sharply reduced by overfishing in recent years, and it is a slow breeder. Furthermore its historic spawning areas are easily targeted for fishing, which tends to remove the reproductively active members of the group. The species is therefore highly vulnerable to overexploitation, and is recognised as endangered on the IUCN Red List. The governments of the United States, the Cayman Islands and the Bahamas have banned fishing for the Nassau Grouper in recent years. In the Cayman Islands fishing in the spawning holes of the grouper has been banned until the end of 2011, and in the case of the Bahamas fishing for the groupers in the months of December 2003 to February 2004 was also stopped. The Nassau Grouper is in a very high rate decline and is at serious risk of becoming extinct.
A large spawning site for the species is located at Glover's Reef, off the Belizean coast. It has been identified as one of only two viable sites remaining for the species, of nine originally known locations. In 2002, a permanent marine protected area was established on Glover's Reef. However, the Nassau Grouper's spawning region is not included in this MPA (marine protected area). Instead, their spawning area (located north of the MPA) is subjected to a three month closure during winter spawning aggregations.[2]
There have been many conservation methods that have been put in place to help the grouper. There are closed seasons when you are not allowed to fish for the grouper. These seasons take place during the spawning season. There are regulations allowing only fish over 3 lbs to be harvested to give the younger fish a chance to spawn. There are protected areas where you are not allowed to fish and there is a complete ban on fishing the grouper in U.S. federal waters. Also there are protections of the spawning sites at all times in certain places.

 Status Reviews

Sadovy and Eklund (1999) is the most complete status review of the species.
Nassau grouper
Nassau grouper in Saba.
The Nassau grouper has been depicted on postage stamps of Cuba (1965, 1975), the Bahamas (1971 5 cent), and Antigua and Barbuda (1987 40c).
The threats to the Grouper are: Over fishing- Fishing during the breeding period.- Habitat loss- Pollution- Invasive species- Catching undersized grouper. There are conservations to try to help protect the grouper against these threats.
The Nassau Grouper was placed on the World Conservation Union’s redlist of threatened species in 1996 and it was determined to be endangered because its population has declined by 60% in the past 30 years. It is estimated that over a third of spawning aggregations have disappeared and the grouper is considered to be commercially extinct in some areas.
The current population of the Nassau Grouper is estimated to be more that 10,000 mature individuals but the population is estimated to still be decreasing. Along with the grouper their suitable habitat is declining. They need quality coral reef habitat to survive. So due to the over fishing and loss of habitat the outlook for the Nassau Grouper is not optimistic.

No comments:

Post a Comment