|Scientific Name:||Mullus surmuletus Linnaeus, 1758|
Mullus barbatus ssp. surmuletus Linnaeus, 1758
Mullus fuscatus Rafinesque, 1810
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Carpenter, K.E., Smith-Vaniz, W.F., de Bruyne, G. & de Morais, L.|
|Reviewer(s):||Polidoro, B., Soto, S. & Weller, S.|
Mullus surmuletus is distributed from Norway and the English Chanel to Dakar, Senegal, including Madeira and the Canary Islands, and is found in the entire Mediterranean and in the Black Sea. It is found at depths ranging from zero to 300 m over sandy and muddy substrates. This species was considered a valuable bycatch species prior to the 1990s, after which it became a major target for small scale and semi-industrial fisheries. It is heavily exploited in the Mediterranean and northeast Atlantic. In the Mediterranean Sea there are few spawning stock biomass (SSB) estimates. Available information from the Balaeric Islands shows reductions in SSB to a series low in 2009. All additional examined stocks are considered overexploited, with recommendations to reduce fishing effort by 40 to 60%, depending on the region. In the northeast Atlantic the population of M. surmuletus appears to be increasing due to warming temperatures. This increase in abundance has led to the development of fisheries which target this species. It is a relatively short lived species which is capable of rapid reproductive turnover. Therefore, it is listed as Least Concern.
|Range Description:||Mullus surmuletus is distributed from Norway and the English Channel to Dakar, Senegal, including Madeira and the Canary islands, and is found in the entire Mediterranean and in the Black Sea. It is found at depths ranging from zero to 300 metres (Golani in press, Vasil'eva 2011).|
Native:Albania; Algeria; Belgium; Bulgaria; Cape Verde; Croatia; Cyprus; Denmark; Egypt; France; Gambia; Georgia; Germany; Gibraltar; Greece; Guernsey; Israel; Italy; Jersey; Lebanon; Libya; Malta; Mauritania; Monaco; Montenegro; Morocco; Netherlands; Norway; Portugal (Madeira); Romania; Russian Federation; Senegal; Serbia; Slovenia; Spain (Canary Is.); Syrian Arab Republic; Tunisia; Turkey; Ukraine; United Kingdom; Western Sahara
|FAO Marine Fishing Areas:|
Atlantic – northeast; Atlantic – eastern central; Mediterranean and Black Sea
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Otolith analysis suggests that the population of Striped Mullet in Northwest European waters can be divided in three geographical zones: The Bay of Biscay, a mixing zone composed of the Celtic Sea and the Western English Channel, and finally a northern zone composed of the Eastern English Channel and the North Sea (Benzinou et al. 2013). Within the Mediterranean Basin, there is a genetic division between the eastern and western subpopulations, separated by the Siculo-Tunisian Strait (Galarza et al. 2009).|
There is geographic morphological variation between northern and southern M. surmuletus which may confound efforts to correctly identify this species in the North Sea bottom trawl surveys. Additional confusion may arise from the use of the same common name, "Red Mullet", for both species (Uiblein 2007).
Global landings reported to the Food and Agriculture Organization (FAO) show landings of M. surmuletus have continuously increased from 1950 (1,000 tonnes) to a peak in 2007 (18,331 tonnes), gradually decreasing to 14,096 tonnes in 2011. The largest landings are reported from Libyan Arab Jamahiriya and France.
The most recent review of scientific advice for 2014 of the Scientific, Technical and Economic Committee for Fisheries (STECF) provides the following insight: In most regions for which information was available, spawning stock biomass (SSB) estimates are not available. The majority of stocks are considered overfished. In the Balaeric Islands this species is overfished. SSB has declined continuously since 2000 to the lowest value of the time series in 2009 and remaining low to 2011. Stocks in the Liguirian and north Tyrrhenian Sea are also overfished, with juveniles representing the majority of the catch. This species is among the most valuable demersal resources off the coast of Egypt, and is also overfished in this area. Throughout the Mediterranean basin recommendations are to reduce fishing mortality (F) by 40 to 60% (STECF 2013).
Catch per unit effort (CPUE) has steadily decreased from 1968 to 2008 in the Balearic Islands, western Mediterranean. Landings and CPUE remained relatively constant from the 1990s to 2008 (Quetglas et al. 2013). Recent stock assessments indicate that stocks of M. surmuletus are considered overfished, and in some cases over-exploited, in the following Mediterranean sub-regions: GSA06, GSA07, GSA09, GSA05, GSA25 (GFCM 2011). Although M. surmuletus undergoes high fishing pressure in the Mediterranean, there have been no decreasing trends in abundance identified in data from a standardized international Mediterranean bottom-trawl survey from 1994 to 1999 (Tserpes et al. 2002). International Bottom Trawl Survey (ITBS) data show fluctuating trends from 1992 to 2012.
In a meeting addressing taxonomic problems for International Council for the Exploration of the Sea (ICES) bottom trawl surveys in the North Sea, several identifications of M. barbatus may have been based on identifications of M. surmuletus, suggesting that there is need to improve onboard identification using keys and training of participating scientists. This species is thought to be an indicator of climate-related temperature increase in the northern Atlantic. There are recent records from 50°N along the Norwegian coast, recorded just south Bergen, in Hardanger Fjord and off coastal Islands in the area. In the eastern part of the North Sea, some small-scale fisheries have been started due to the increased abundance. It is also found in the Kattegat area. It is still rare further north. The same trends have been reported from Scotland and the Shetland Islands. Temperature increases in the 1930s resulted in similar range expansions (Uiblein 2007).
|Current Population Trend:||Unknown|
|Habitat and Ecology:||This species is sympatric with M. barbatus, however there is partial differentiation in habitat use between these two species (Lombarte et al. 2000). Off the island of Majorca, the highest concentration of this species is found between 30 and 70 m, replaced in deeper water by M. barbatus (Reñones et al. 1995), a difference in bathymetrical distribution which has also been recorded along the Catalonian coast (Sánchez et al. 1983) and in Israel (Golani and Galil 1991). It can reach a maximum size of 40 cm, however it is more commonly seen at 10 to 22 cm SL. Off the Island of Majorca, in the northwestern Mediterranean, 50% of males and females mature at 15 and 16.8 cm, corresponding to an age of one. All individuals are immature under 13 cm, and are mature after reaching 26 cm. Otolith age reading indicated that the subpopulation exploited in the trawl fishery off this island consisted of six age classes, including a very high proportion of individuals between zero and four years old. Females grow relatively slowly, and attain greater asymptotic sizes, than males. The months of maximum reproductive activity are from March to May (Reñones et al. 1995). Migrations to shallow waters (from 10 to 40 meters in depth) by mature adults occur in the spring and summer, followed by a concentration of juveniles close to the coast in summer and autumn. Juveniles recruit in shallow waters and move to deeper waters as they grow (Gharbi and Ktari 1981).|
Off the Canary Islands, total length ranged from 12 to 33 cm, mainly between 15 and 21 cm. Males ranged from 14 to 26 cm and females from 14 to 33 cm. Females dominated the larger size-classes (>18 cm). The overall ratio of males to females was 1:2.3. The reproductive period extended from February to May, spawning peaking in March and April. The total length at 50% maturity was 16.6 cm for the whole population. The length-mass relationship for all individuals can be described by the parameters a = 0.0074 and b = 3.1826. Fish aged zero to eight years were present in the samples. The parameters of the Von Bertalanffy growth equation obtained for all individuals were: L∞ = 35.71 cm and k = 0.22·year−1. Significant differences were found in the growth parameters between males and females. The rates of total mortality Z, natural mortality M and fishing mortality F were 1.25, 0.55 and 0.70·year−1 respectively. The estimated total length at first capture was 15.74 cm (Pajuelo et al. 1997).
|Use and Trade:||Mullus surmuletus was considered a valuable bycatch species prior to the 1990s, after which it became a major target for small scale and semi-industrial fisheries. It is heavily exploited in the Mediterranean and northeast Atlantic (Vogiatzi et al. 2012). The Bay of Biscay and Eastern English Channel are the two main areas where this species is caught in the northeast Atlantic (Benzinou et al. 2013). The increase of catches in the northeast Atlantic is primarily due to French trawlers, and supplemented by the Netherlands and United Kingdom Fleets (Mahé et al. 2005). In the Mediterranean, this highly-desirable species is the main target of many demersal fisheries and is considered heavily fished (Tserpes et al. 2002). Mullus surmuletus is caught primarily by trammel nets and by trawl (Golani in press). Mullus surmuletus is on of the main target species of the trawling fishery along the continental shelf off the Island of Majorca, in the northwestern Mediterranean (Reñones et al. 1995).|
Over-exploitation in the Mediterranean
Mullus surmuletus is a commercial species throughout its range. It is a major target for small scale and semi-industrial fisheries, and is heavily exploited in the Mediterranean and northeast Atlantic (Vogiatzi et al. 2012). Despite being taken as bycatch in the reason prior to the 1990s, and being directly targeted in the region since the 1990s, Mullus surmuletus is a non-quota species in the northeast Atlantic (Benzinou et al. 2013). In the Mediterranean, two of the three anaged stocks are considered to be over-exploited, and recommendations have been made to not increase fishing mortality, to reduce fishing mortality, and to reduce the percentage small individuals in the catch. In the Mediterranean, catches mostly consist of animals less than 15 cm TL which have not yet completed their second year of life (Tserpes et al. 2002). High fishing pressure has been implicated as a cause for the dominance of young individuals in catches (Caddy 1993, Farrugio et al. 1993). The dominance of young individuals implies an extreme vulnerability to recruitment fluctuations in Mullus stocks, which are heavily fished (Farrugio et al. 1993). Protection of spawning and nursery areas seems to be crucial for the conservation of M. surmuletus (Tserpes et al. 2002).
Mediterranean fisheries are concentrated along coastal areas, where biodiversity is greatest. The majority (80%) of the Mediterranean fleet is comprised of vessels <12 m, and as such Mediterranean fisheries can be thought of as small-scale artisanal fisheries. Additionally, fisheries tend to be multi-species. As such it is difficult and expensive to obtain data for stock assessment purposes. There are several issues of concern which include the widespread targeting of small species or larger juvenile finfish prior to maturity, the observed reduction in the mean trophic level of Mediterranean catches, and high discard rates (40 to 56% of the catch taken in waters < 150 m) and the reduction in mean abundance of piscivorous species (Vassilopoulou 2010).
According to a 2013 synthesis of the Status of Mediterranean and Black Sea resources in European Waters, while the state of knowledge on the Mediterranean and Black Sea stocks is improving rapidly, between 94% and 95% of stocks analysed are overexploited. Recent observed reductions in nominal fishing effort have not resulted in declines in fishing mortality. Overall reductions between 45% and 51% are needed in order to reach maximum sustainable yields (Cardinale and Osio 2013).
Demersal fisheries in west Africa
Coastal demersal resources are very sought after in all four of the northern CECAF zone countries (Mauritania, Morocco, Senegal and the Gambia). Many of the commercially important demersal resources of Northwest Africa are heavily exploited (FAO 2011).They are exploited by both national artisanal fleets and foreign industrial fleets. Demersal fisheries are typically multi-purpose, and many demersal fisheries resources are by-catch of more specialized fisheries, such as the cephalopod, hake or shrimp fisheries. High fishing pressure is exerted all on demersal fish species in this region
Upeneus moluccensis (eastern Aegean to Libya) and Upeneus pori (eastern Levant) are Lessepsian invaders in the Mediterranean; these species have displaced the native M. surmuletus to deeper waters (Golani 1994), but direct impacts have not been documented. In the eastern Levant, U. moluccensis is commercially important, while U. pori is caught in large numbers but due to its small size, is not commercially important (Golani in press).
|Conservation Actions:||Mullus surmuletus is a well-researched and managed species in the Mediterranean. Stock assessments are performed regularly by sub-region in the Mediterranean basin. It is well researched in the northeast Atlantic as well, although relative to the Mediterranean it has received less research attention. It is found in marine protected areas throughout its range. There is a need for more research and monitoring of population trends in this species.|
|Citation:||Carpenter, K.E., Smith-Vaniz, W.F., de Bruyne, G. & de Morais, L. 2015. Mullus surmuletus. The IUCN Red List of Threatened Species 2015: e.T198674A42691804.Downloaded on 20 September 2017.|
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