Tuesday 21 May
In the News: First crane egg in the western UK in four centuries

What’s the World’s Favourite Species?
Find out here.| Kingdom | Animalia |
| Phylum | Chordata |
| Class | Actinopterygii |
| Order | Perciformes |
| Family | Serranidae |
| Genus | Epinephelus (1) |
The Nassau grouper (Epinephelus striatus) is one of the larger reef fish and one that has suffered a dramatic decline during the 20th Century, primarily as a result of overfishing (3). These large groupers have a robust, oblong body; the background colour varies from light buff to pinkish red, depending on depth (4). There are five vertical brown bars, a brown saddle near the base of the tail and distinctive facial markings (5). Individuals are capable of altering their colour pattern to resemble that of the surrounding environment or as a means of communication (4).
Adults are generally solitary, with the exception of spawning events when hundreds to thousands of individuals were known to group together. In the southern extent of the grouper's range, these awesome aggregations occurred between December and February whilst those in northern waters fell between May and August (5). Historically, the same sites are used and the triggers that cause individuals to arrive appear to be related to the full moon and the temperature of the water (5). Complex courtship displays take place, culminating in the synchronised release of sperm and eggs at sunset; fertilisation thus occurs in the open water (4). Contrary to previous opinion, evidence now suggests that individual Nassau groupers occur as separate sexes and do not change from female to male, as many other groupers do (5). Juveniles usually settle in sea grass beds or clumps of coral (6) when they have reached roughly 32 millimetres in size; having previously spent around five weeks in the plankton as larvae (4).
Groupers are usually found towards the bottom of the water column where they feed on a variety of prey, using their cryptic appearance to ambush fish such as parrotfish and wrasse (4). They are regular visitors to cleaning stations where small cleaning wrasse or shrimps will remove parasites from inside the grouper's mouth. Nassau groupers are long-lived, surviving for over 20 years in the wild (3).
TopFound in the tropical western Atlantic Ocean and the Caribbean Sea (4). Nassau groupers are known from Bermuda, the Bahamas and southern Florida coasts south to Central America and northern South America (6).
See this species on Google Earth.
TopNassau groupers are found in shallow waters up to 90 metres deep, associated with reef or rocky substrate (4).
TopThe Nassau grouper is classified as Endangered (EN) on the IUCN Red List (1).
TopThe Nassau grouper was historically an important commercially harvested fish throughout the region; indeed, it is the most important finfish in the Bahamas (6). The behaviour of massing in predictably located spawning aggregations has meant that these fish are easy targets, caught by hook and line, traps and spearguns (6). In the 1990s however, fisheries documented a worrying decline in the size of catches, and aggregations are no longer observed in Puerto Rico, Bermuda or the United States Virgin Islands (3).
TopFollowing a massive lobbying effort by conservationists, the Nassau grouper has finally received some of the protection it requires if numbers are going to recover from past exploitation (3). Spawning sites are protected in the Cayman Islands and fishing is banned in Belize during the spawning season (1). Other countries in the area however, have been slow to introduce protection measures and extensive lobbying continues (1).
TopFor more on the Nassau grouper:
Authenticated (30/6/03) by Yvonne Sadovy, Society for the Conservation of Reef Fish Aggregations (SCRFA).
http://www.scrfa.org/
More »Related species
Image credit
© Jurgen Freund / naturepl.com
Nature Picture Library
5a Great George Street
Bristol
BS1 5RR
United Kingdom
Tel: +44 (0) 117 911 4675
Fax: +44 (0) 117 911 4699
info@naturepl.com
http://www.naturepl.com
Link to this photo
Embed this ARKive thumbnail link by copying and pasting the code below.
Terms of Use - The displayed thumbnail may be used as a link from your website to ARKive's online content for private, scientific, conservation or educational purposes only. It may NOT be used within Apps.
Read more about
MyARKive
MyARKive offers the scrapbook feature to signed-up members, allowing you to organize your favourite ARKive images and videos and share them with friends.
Terms and Conditions of Use of Materials
Copyright in this website and materials contained on this website (Material) belongs to Wildscreen or its licensors.
Visitors to this website (End Users) are entitled to:
End Users shall not copy or otherwise extract, alter or manipulate Material other than as permitted in these Terms and Conditions of Use of Materials.
Additional use of flagged material
Green flagged material 
Certain Material on this website (Licence 4 Material) displays a green flag next to the Material and is available for not-for-profit conservation or educational use. This material may be used by End Users, who are individuals or organisations that are in our opinion not-for-profit, for their not-for-profit conservation or not-for-profit educational purposes. Low resolution, watermarked images may be copied from this website by such End Users for such purposes. If you require high resolution or non-watermarked versions of the Material, please contact Wildscreen with details of your proposed use.
Creative commons material
Certain Material on this website has been licensed to Wildscreen under a Creative Commons Licence. These images are clearly marked with the Creative Commons buttons and may be used by End Users only in the way allowed by the specific Creative Commons Licence under which they have been submitted. Please see http://creativecommons.org for details.
Any other use
Please contact the copyright owners directly (copyright and contact details are shown for each media item) to negotiate terms and conditions for any use of Material other than those expressly permitted above. Please note that many of the contributors to ARKive are commercial operators and may request a fee for such use.
Save as permitted above, no person or organisation is permitted to incorporate any copyright material from this website into any other work or publication in any format (this includes but is not limited to: websites, Apps, CDs, DVDs, intranets, extranets, signage, digital communications or on printed materials for external or other distribution). Use of the Material for promotional, administrative or for-profit purposes is not permitted.