Epinephelus marginatus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Perciformes Epinephelidae

Scientific Name: Epinephelus marginatus
Species Authority: (Lowe, 1834)
Regional Assessments:
Common Name(s):
English Dusky Grouper
Spanish Mero, Mero Moreno
French Méerou brun
Epinephelus guaza (Linneaus, 1758)
Taxonomic Source(s): Ma, K.Y., Craig, M.T., Choat, J.H. and van Herwerden, L. 2016. The historical biogeography of groupers: Clade diversification patterns and processes. Molecular phylogenetics and evolution 100: 21-30.

Assessment Information [top]

Red List Category & Criteria: Endangered A2d ver 3.1
Year Published: 2004
Date Assessed: 2004-04-30
Needs updating
Assessor(s): Cornish, A. & Harmelin-Vivien, M. (Grouper & Wrasse Specialist Group)
Reviewer(s): Sadovy, Y. & Harmelin-Vivien, M. (Grouper & Wrasse Red List Authority)
Of the two discontinuous distributions for Epinephalus marginatus in Africa/Europe and South America, that of the former is far larger and it is assumed that most of the global population lies in this area. Information concerning the actual global population of this species remains fragmentary and incomplete, but annual landings data exist for many countries in the range of this species in Africa/Europe. Comparable data are not available for South America although this species is known to be important in artisinal fisheries and to spearfishers along Santa Catarina in Brazil (Andrade et al. 2003). Landings data can be used as a crude proxy for changes in population size provided fishing effort, gear types, management regulations, etc., do not also change over time in a way that could cause landings to change accordingly. In this instance, changes in fishing effort/management, that could explain the large declines in landings seen from 1990–2001 (up to 95%, in Italy) are not known. There is some of evidence of localized recovery in France, but on a very small scale compared to the declines in landings over many of the countries where E. marginatus occurs.

E. marginatus is widely targeted across its global range as adults for food, and is extremely slow to reach sexual maturity (around 5 years in females and 12 years in males). It also forms spawning aggregations which are particularly vulnerable to overfishing, and as such, shows low resilience to fishing (see Habitat and Ecology). Furthermore, the observed sex ratio of sexually mature males to females in one spawning aggregation was approximately 1:7 (Zabala et al. 1997a). The sex ratio is heavily skewed towards females, and may become more so, if fishing is targeted towards the largest individuals (males). Heavily skewed sex ratios may lead to reductions in reproductive output.

Although fisheries data is lacking from many countries within its range, the alarming declines seen in Europe and around the Mediterranean, along with reports that spawning aggregations are being targeted in Brazil, as well as the fact that this is a very large grouper and that large size is a biological characteristic clearly shown to be associated with higher risk of extinction, demands a precautionary approach when assessing the global threat of extinction in this species. Based on a decline of 88% in total catches for seven countries between 1990–2001 in a significant part of its overall geographic range and that western African waters for which there are few data are typically heavily fished, E. marginatus is assessed as being Endangered due to a suspected population size reduction of well over 50% over the last three generations, where the causes of the reduction have not ceased (i.e., EN A2d).

For a summary of the available fisheries data and information on regional status, see the supplementary material.
For further information about this species, see 7859_Epinephelus_marginatus.pdf.
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Previously published Red List assessments:

Geographic Range [top]

Range Description:Epinephelus marginatus occurs in the eastern Atlantic and western Indian Ocean: Mediterranean Sea and round the southern tip of Africa, except for Namibia (S. Fennessy, pers. comm. 2004) to southern Mozambique. Western Atlantic: southern Brazil, and from Uruguay and Argentina (see FishBase). Also reported from southern Oman (Randall 1995). Reports from Madagascar are likely in error (M. Harmelin-Vivien, pers. comm. 2004) For this species, which aggregates to spawn, area of occupancy is taken as the area of all aggregations sites. This area, which will occupy < 10% extent of occurrence, is not known. Known or suspected reproductive sites in the north-western Mediterranean Sea: Corisca (Revellata, Lavezzi Islands), Var (Les Embiez, National Park of Port-Cros), Pyrenees-Orientales coasts (Bodilis et al. 2003), Medes Islands (Zabala et al. 1997a) and Lampedusa Island (Marino et al. 2001).
Countries occurrence:
Albania; Algeria; Angola (Angola); Benin; Brazil; Cameroon; Cape Verde; Congo; Congo, The Democratic Republic of the; Côte d'Ivoire; Croatia; Cyprus; Egypt; Equatorial Guinea; France (Corsica); Gabon; Gambia; Ghana; Gibraltar; Greece (East Aegean Is., Kriti); Guinea; Guinea-Bissau; Israel; Italy (Sardegna, Sicilia); Lebanon; Liberia; Libya; Malta; Mauritania; Monaco; Montenegro; Morocco; Mozambique; Namibia; Nigeria; Portugal (Azores, Madeira); Senegal; Sierra Leone; Slovenia; South Africa; Spain (Baleares, Canary Is.); Syrian Arab Republic; Togo; Tunisia; Turkey; United Kingdom; Western Sahara
FAO Marine Fishing Areas:
Atlantic – northeast; Atlantic – southeast; Atlantic – southwest; Atlantic – eastern central; Indian Ocean – western; Mediterranean and Black Sea
Additional data:
Lower depth limit (metres):300
Upper depth limit (metres):8
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:It is highly likely that the two primary areas where E. marginatus occurs, in eastern Africa/Europe and South America represent (at least) two separate subpopulations with minimal gene flow due to the very large distance between them.

In France, Spain and Italy, this species is abundant only in Marine Protected Areas (MPAs) where fishing is totally banned. A fish survey conducted for more than ten years demonstrates an increase in the population of the Dusky Grouper inside MPAs. The fish is much more abundant in the southern part of the Mediterranean than in the north. The population of E. marginatus has never been very numerous along the French Mediterranean coast. But a dynamic population of groupers has been recorded in the northern Mediterranean for 15 years (Harmelin and Robert 2001). Visual censuses conducted in Ustica Island revealed a high abundance of the grouper in coastal areas (La Mesa and Vacchi 1999).

A recovery in the Dusky Grouper population has been observed in France, first in MPAs and now even in unprotected areas. A tenfold increase was observed in the French National Park of Port-Cros for the last 10 years. The increase is believed to be related to several factors acting in synergy: increased number of MPAs, spearfishing ban and global warming of the Mediterranean Sea (M. Harmelin-Vivien, pers. comm. 2003).

The presence of small groupers is constantly observed in the south of Spain and along the North African coasts. The presence of many small Dusky Groupers were also observed in Corsica between 1990, 1992, 1996 and 2001 (Bodilis et al. 2003). However, a decline in populations has been observed in Tunisia and southern Spain due to overfishing (reported by scientists of these countries at the 1998 Symposium on Mediterranean groupers).
Current Population Trend:Decreasing
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:E. marginatus inhabits rocky reefs from 8–300 m (see species account on FishBase). It is a protogynous hermaphrodite, changing from female to male at large size.

Females in Tunisian waters reached sexual maturity at age 5, while sex reversal of females to males takes place between the 9th and 16th years with a maximum at the12th year (Chauvet 1988). In Brazil, 50% of females reach sexual maturity at 47 cm while the largest female was 79 cm and the smallest male was 80 cm. The species matures in spring and spawns in early summer with a peak in December (Andrarde et al. 2003).

E. marginatus forms small spawning aggregations of a few tens of individuals. (Zabala et al. 1997a, Zabala et al. 1997b). Aggregation sites are known from the Medes Islands Marine Reserve, Spain (Zabala et al. 1997a), off Lampedusa Island in the Mediterranean (Marino et al. 2001), and the National Park of Port-Cros, France (Chauvet and Francour 1991). Aggregation sites also appear to exist in Brazil as spearfishermen have reported large catches (up to 400 kg) in a few days from the same areas (Andrarde et al. 2003).

In the Medes Island Marine reserve in Spain, density of Dusky Grouper was low in winter and maximal in summer, which took place from late June to late August (up to 8–fold increase). The number continued to increase before spawning in mid August, then dropped rapidly afterwards. During this period, dominant males developed territorial behaviour and displayed aggressively towards neighbouring males and smaller females. The observed sex ratio was approximately 1:7 (sexually active males versus adult females) (Zabala et al. 1997a).

Threats [top]

Major Threat(s): Overexploitation from commercial fishing is the primary threat. The slow growth rate and the complex reproductive style of E. marginatus compound its inability to withstand high fishing pressure (Fennessy 1998).

In the past, spearfishing has been the main cause of mortality in France. Furthermore, the possible removal of legal protection of dusky groupers and a resumption of spearfishing will further impact the re-established juvenile population (Bodilis et al. 2003).

Conservation Actions [top]

Conservation Actions: A spearfishing ban has been imposed on the species for ten years in France. A number of Marine Protected Areas have been established to protect the habitat of the fish.

In South Africa, E. marginatus forms part of a ‘restricted’ group of species governed by a bag limit of five fish per day (S. Fennessy, pers. comm., 2003).

Citation: Cornish, A. & Harmelin-Vivien, M. (Grouper & Wrasse Specialist Group). 2004. Epinephelus marginatus. The IUCN Red List of Threatened Species 2004: e.T7859A12857009. . Downloaded on 11 December 2016.
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