Epinephelus marginatus 

Scope: Europe
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Perciformes Epinephelidae

Scientific Name: Epinephelus marginatus (Lowe, 1834)
Regional Assessments:
Common Name(s):
English Dusky Grouper, Yellowbelly Grouper, Yellowbelly Rockcod
French Méerou brun
Spanish Mero, Mero Moreno
Epinephelus guaza (Linneaus, 1758)
Taxonomic Source(s): Craig, M.T. and Hastings, P.A. 2007. A molecular phylogeny of the groupers of the subfamily Epinephelinae (Serranidae) with a revised classification of the Epinephelini. Ichthyological Research 54(1): 1-17.

Assessment Information [top]

Red List Category & Criteria: Endangered A2d (Regional assessment) ver 3.1
Year Published: 2015
Date Assessed: 2015-02-02
Assessor(s): Harmelin-Vivien, M. & Craig, M.T.
Reviewer(s): Pollard, D.A., Harmelin, J.-G., Kemp, J.R. & Allen, D.J.
Contributor(s): Cornish, A.
European regional assessment: Endangered (EN)

In the European region, the species occurs throughout the Mediterranean Sea and in the eastern Atlantic Ocean from the eastern English Channel (exceptionally) to Portugal, Spain and the Macaronesian Islands. The species has undergone historical declines in population as a result of fishing pressures; the species is widely targeted across its European range as adults for food. The fish is long-lived (up to 52 years for females and 61 years for males; Reñones et al. 2007) and extremely slow to reach sexual maturity (around five years in females and 12 years in males). It also forms spawning aggregations that are particularly vulnerable to overfishing, and as such, the fish shows low resilience to fishing pressures. Furthermore, the observed sex ratio of sexually mature males to females in one spawning aggregation was approximately 1:7. The sex ratio is heavily skewed towards females, and may become more so if fishing is targeted towards the largest individuals (i.e., mainly males). The heavily skewed sex ratios may lead to reductions in the species' reproductive output.

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. Although fisheries data are not ideal for quantitatively estimating population sizes, E. marginatus has many characteristics that make it vulnerable to fishing pressure, more so than many other marine fish species. The synergistic effects of these intrinsic biological threats coupled with the apparently high level of exploitation in the past demands a precautionary approach when assessing the global threat of extinction in this species. There has been a decline of nearly 89% in reported landings from the European region for 1993–2011; although these declines could possibly be partially explained by changes in fishing effort/management, the drastic reduction in landings prior to the establishment of regulations strongly suggests that a significant population reduction has occurred. It is inferred that population declines of well over 50% have occurred over the last three generation lengths; therefore, E. marginatus is assessed as Endangered under A2d.

Geographic Range [top]

Range Description:In the European region, the species occurs throughout the Mediterranean Sea and in the eastern Atlantic Ocean from the eastern English Channel (Mahé et al. 2012) to Portugal, Spain and the Macaronesian Islands.

Outside the European region, the species is known from the eastern and western Atlantic Ocean and the western Indian Ocean: from the Mediterranean Sea southwards, and around the southern tip of Africa, except for Namibia (S. Fennessy pers. comm. 2004) to southern Mozambique. In the western Atlantic Ocean it is known from southern Brazil, and from Uruguay and Argentina. It is also reported from southern Oman (Randall 1995). The species was reported from the south of Madagascar (Randall and Heemstra 1991), with an underwater photograph taken by Pierre Laboute in 2010 (not seen by the assessors; M. Harmelin-Vivien pers. comm. 2014).

For this species, which aggregates to spawn, the area of occupancy (AOO) is taken as the area of all aggregation sites. This area, which will occupy less than 10% of the extent of occurrence (EOO), is not however known. The known or suspected reproductive sites in the northwestern Mediterranean Sea include: Corsica (Revellata, Lavezzi Islands), Var (Les Embiez, National Park of Port-Cros), Pyrénées-Orientales coasts (Bodilis et al. 2003), Medes Islands (Zabala et al. 1997a) and Lampedusa Island (Marino et al. 2001). In the eastern Atlantic Ocean, spawning sites are known or suspected in the Macaronesian Islands and on the Portuguese coast.
Countries occurrence:
Albania; Algeria; Bosnia and Herzegovina; Croatia; Cyprus; Egypt (Egypt (African part), Sinai); France (Corsica, France (mainland)); Gibraltar; Greece (East Aegean Is., Greece (mainland), Kriti); Guernsey; Israel; Italy (Italy (mainland), Sardegna, Sicilia); Jersey; Lebanon; Libya; Malta; Monaco; Montenegro; Morocco; Palestinian Territory, Occupied; Portugal (Azores, Madeira, Portugal (mainland), Selvagens); Slovenia; Spain (Baleares, Canary Is., Spain (mainland), Spanish North African Territories); Syrian Arab Republic; Tunisia; Turkey (Turkey-in-Asia, Turkey-in-Europe); United Kingdom (Great Britain)
FAO Marine Fishing Areas:
Atlantic – northeast; Atlantic – eastern central; Mediterranean and Black Sea
Additional data:
Lower depth limit (metres):300
Upper depth limit (metres):1
Range Map:7859-1

Population [top]

Population:FAO (Food and Agriculture Organisation of the United Nations) capture production statistics show a marked decline in landings for Europe from the early 1990s when fishery production peaked at 7,699 metric tonnes in 1994, to 869 mt (estimated) in 2011 (FAO 2014; assessment region countries only), representing an approximately 89% decline. However, landings data are a poor proxy for population declines, particularly as changes in fishing effort or reporting can change through time, such that a 89% decline in landings does not necessarily mean that there has been a decline of more than 80% in the population, but an overall population decline of at least 50% is suspected within the region.

The largest producers of Dusky Grouper were Italy, Spain and Portugal (in decreasing order of contributions to the European production). Numerous studies have documented increases in population trends over the past decade given an increase in the establishment of marine protected areas (e.g., Reñones et al. 1999, Hackradt et al. 2014), however these increases are small relative to the presumed abundance of the species prior to its exploitation in the European region. 
Reñones et al. (2010) claimed that the dusky grouper was considered to be overexploited over its entire [presumably European] distribution range. Therefore, the species is thought to be declining in Europe.

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 20 years (Harmelin and Robert 2001, Harmelin 2013). Visual censuses conducted around Ustica Island off the northern coast of Sicily revealed a high abundance of the grouper in protected 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 more than five-fold increase was observed in the French National Park of Port-Cros over the last 18 years (1996-2014). The increase is believed to be related to several factors acting in synergy: increased number of MPAs, spearfishing bans, and warming of the Mediterranean Sea (Harmelin 2013).

The presence of small groupers is constantly observed in the south of Spain, around the Balearic Islands, and along the North African coast. The presence of many small Dusky Groupers was also observed in Corsica in 1990, 1992, 1996 and 2001 (Bodilis et al. 2003), and at Porquerolles Island in 2008 (France, mainland) (Cottalorda et al. 2009). However, a decline in populations has been observed in Tunisia and southern Spain due to overfishing as reported by scientists of these countries at the Second International Symposium on the Mediterranean Groupers (Francour and Gratiot 1998).
Current Population Trend:Decreasing
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:The species inhabits rocky reefs and bottoms from one to c. 300 m (Reiner 1996, in the Cape Verde Islands), and to c. 250 m (Bruslé 1985, in European waters), but maximum densities are found more usually to 50 m (Heemstra and Randall 1993, Harmelin and Harmelin-Vivien 1999, Louisy 2005, Andrello et al. 2013). It is a monandric protogynous hermaphrodite, changing from female to male with increase in size. The females in Tunisian waters reached sexual maturity at age five, while sex reversal of females to males takes place between the ninth and sixteenth years with a maximum at the twelfth year (Chauvet 1988). In the Balearic Islands, females reached sexual maturity at 49 cm (TL) and six years, while the occurrence of some of them in the largest and oldest classes indicated that sex reversal can be notably delayed, inducing a greater oocyte production due to the increase of fecundity with size and age (Reñones et al. 2010). In Brazil, 50% of females reach sexual maturity at 49 cm while the largest female was 79 cm and the smallest male was 80 cm. The species matures in spring and spawns in summer with a peak in July and August in the northwestern Mediterranean Sea (Hereu et al. 2006, Reñones et al. 2010) and December in Brazil (Andrade et al. 2003). The species can live for 52 years for females and 61 years for males, but exploited populations in Spain are dominated by four to eight year-old individuals (Reñones et al. 2007).

The species forms small spawning aggregations of a few tens of individuals (Zabala et al. 1997a,b). In European waters, aggregation sites are known in the Mediterranean Sea from the Medes Islands Marine Reserve, Spain (Zabala et al. 1997a, Hereu et al. 2006), off Lampedusa Island, Italy (Marino et al. 2001), and the National Park of Port-Cros, France (Chauvet and Francour 1990); and in the Atlantic Ocean from the Azores (Barreiros 1995). Spawning sites certainly exist around other Atlantic islands (Madeira, Canaries) and probably also in southern Portugal, but there are no formal records.

In the Medes Island Marine reserve in Spain, the density of Dusky Grouper was low in winter and maximal in summer, which took place from late June to late August (up to an eight-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).
Generation Length (years):7
Movement patterns:Unknown
Congregatory:Congregatory (and dispersive)

Use and Trade [top]

Use and Trade: This is one of the most targeted groupers in fishery activities (including spearfishing).

Threats [top]

Major Threat(s): The over-exploitation from commercial fishing and leisure (spearfishing) is the primary threat. The slow growth rate and the complex reproductive style of the species compounds its inability to withstand high fishing pressure (Fennessy 1998, 2000).

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 in France, Monaco, and the Azores. A number of marine protected areas (MPAs) have been established to protect the habitat of the fish throughout various parts of the Mediterranean Sea, and the species is recorded from 25 Natura 2000 sites in Italy, France and Spain (EUNIS 2014).

Renones et al. (2010) recommended a “slot” size limit for capture of individuals between 50 and 80 cm TL, and suggested that sanctuary zoned MPAs may be the most effective management measure to facilitate its population recovery.

The species was assessed globally in 2004 as Endangered (Cornish and Harmelin-Vivien 2004).

Citation: Harmelin-Vivien, M. & Craig, M.T. 2015. Epinephelus marginatus. The IUCN Red List of Threatened Species 2015: e.T7859A44904558. . Downloaded on 23 February 2018.
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