|Scientific Name:||Merluccius merluccius (Linnaeus, 1758)|
Gadus merluccius Linnaeus, 1758
Gadus ruber Lacepède, 1803
Hidronus marlucius Minding, 1832
Merluccius argentatus Günther, 1862
Merluccius esculentus Risso, 1827
Merluccius linnei Malm, 1877
Merluccius smiridus Rafinesque, 1810
Merluccius vulgaris Fleming, 1828
Merlucius ambiguus Lowe, 1841
Merlucius lanatus Gronow, 1854
Merlucius sinuatus Swainson, 1838
Onus riali Rafinesque, 1810
Trachinoides maroccanus Borodin, 1934
Trachinoides moroccanus Borodin, 1934
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Fernandes, P., Cook, R., Florin, A.-B., Lorance, P. & Nedreaas, K.|
|Reviewer(s):||Polidoro, B. & Carpenter, K.E.|
|Contributor(s):||Di Natale, A., Molinari, A., Öztúrk, B., Srour, A. & Pollard, D.A.|
|Facilitator/Compiler(s):||Polidoro, B. & Carpenter, K.E.|
Merluccius merluccius is distributed in the eastern Atlantic from Norway and Iceland, south to Mauritania, and including the Mediterranean Sea. In the North east Atlantic, this species appears to be expanding its range, and is managed as two distinct stocks (northern and southern). Trends in spawning stock biomass (SSB) are variable. Based on estimates of SSB for the northern stock, which is the larger of the two, over the last five years SSB has increased by a factor of five. The southern stock is still slightly overfished, but SSB over the past 10 years has been increasing. Therefore, M. mercluccius is assessed as Least Concern.
However, it is important to note that subpopulations in the Mediterranean were previously assessed as Vulnerable due to declines in abundance which were attributed to high fishing pressure in the region. In the Mediterranean, there is no current evidence of reducing fishing or recovery of this species, and declines are likely greater than 30% over the past 20-40 years based on reported FAO landings. Fishing mortality is currently well above Fmsy for most stocks in the Mediterranean region, and this species is considered to be overfished throughout the Mediterranean region. No current estimates of biomass or SSB trends are available. Juveniles are also extensively fished in this region. Better data and management for this species is needed in the Mediterranean region.
|Range Description:||Merluccius merluccius is distributed in the east Atlantic from Norway and Iceland, south to Mauritania and including the Mediterranean Sea (Svetovidov 1986). The distributional limit of this species in the Baltic Sea is the Kattegat (HELCOM 2013). It has been found in depths ranging from 30 to 1,075 m (Lloris et al. 2005) but is most often found between 70 and 400 m (Muus and Nielsen 1999). |
Genetic testing indicates that a subspecies of M. merluccius may be forming in the southern extremity of this species range (Roldan et al. 1998).
Native:Albania; Algeria; Belgium; Croatia; Cyprus; Denmark; Egypt (Egypt (African part), Sinai); France (Corsica, France (mainland)); Georgia; Germany; Gibraltar; Greece (East Aegean Is., Greece (mainland), Kriti); Guernsey; Iceland; Ireland; Israel; Italy (Italy (mainland), Sardegna, Sicilia); Jersey; Lebanon; Libya; Malta; Mauritania; Monaco; Montenegro; Morocco; Netherlands; Norway; Portugal (Azores, Portugal (mainland)); Slovenia; Spain (Baleares, Canary Is., Spain (mainland), Spanish North African Territories); Sweden; Syrian Arab Republic; Tunisia; Turkey; United Kingdom (Great Britain, Northern Ireland)
|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.|
There are two stocks for this species, the northern and the southern. Based on estimates of spawning stock biomass (SSB) for the northern stock, which is the larger of the two, over the last five years, SSB has increased by a factor of five. This species appears to be expanding its area (P. Fernandes pers. comm. 2013). The southern stock is still slightly overfished, but SSB over the past 10 years has been increasing (ICES 2013).
There has recently been evidence of spawning in Kattegat, which may also indicate recolonization (HELCOM Fact Sheet).
The Atlantic population structure appears to be more complex than previously suggested by the placement of stock boundaries by the International Council for the Exploration of the Seas (ICES). Analyses based on various models of microsatellite evolution all suggest that differentiation exists between Bay of Biscay and Portuguese samples, θ = 0.013 (P < 0.001), RST = 0.036 (P < 0.001) which are currently managed as one stock. By contrast, fixation indices indicated no differentiation between southern Bay of Biscay samples and Celtic Sea samples, θ = 0.003 (P = 0.02), φST = 0.007 (P = 0.10) which are managed as separate stocks. These results suggest that if the observed trends are stable through time, current management policy of European Hake may need revision (Lundy et al. 1999).
This species shows certain genetic differences between the subpopulations in the Atlantic and the Mediterranean Sea. Results of genetic testing identify the boundary between Atlantic and Mediterranean stocks more precisely in the Almeria-Oran front (AOF), instead of the Gibraltar Strait, as generally postulated by previous studies. This leads to the conclusion that the Alboran Sea is a zone of steep transition between Atlantic and Mediterranean Sea subpopulations (Cimmaruta et al. 2005).
FAO landings statistics summary:
Landings are reported from the following FAO fishing areas: Mediterranean, Eastern Central Atlantic (ECA) and Northeast Atlantic (NEA). The overall trend in landings is one of continuous, steady decline from the beginning of the time series (1950) to present (2011). Landings have declined approximately 30% over the this time series, from 131,600 tonnes in 1950 to 94,166 tonnes in 2011. In the past 10 years, global landings have increased from 57,194 tonnes in 2001 to 94,166 in 2011.
The global trend in landings is driven by landings in the Northeast Atlantic Fishing Area, which accounted for greater than 80% of total landings until the 1970s, and has accounted for 45-65% of total landings in the last 10 years. In the last 10 years, landings from this area have fluctuated, with a gradual increase from 33,731 tonnes reported in 2003 to 55,407 tonnes reported in 2011. Spain and France reported the majority of landings originating from the Northeastern Atlantic.
The Mediterranean Fishing Area accounts for the second largest proportion of total reported landings, and has accounted for between 40% and 20% of total landings in the last 10 years. The trend in Mediterranean landings is one of gradual increase to a peak of 48,280 tonnes in 1995, followed by a gradual decrease of (38%) to 18,425 tonnes in 2011. The trend in landings over the last 10 years is one of gradual decline (approximately 20% decline) with some fluctuation. Morocco accounts for the large majority of landings declared in the Mediterranean, followed by Spain.
Population Information by region: NEA General Information
ICES assumes two different stock units, although there is no biological basis for this - a widely distributed northern stock, and a southern stock. There are two major nursery areas in the Bay of Biscay and off southern Ireland. This species is widely distributed in the NEA; spawning stock biomass in the northern part of its range (from Kattegat down to the Bay of Biscay) has been increasing since 1998, and is estimated to be at a record high (ICES 2011).
Population Information by region: Mediterranean
This species is among the main target species of the demersal fisheries of the Mediterranean (Gucu and Bingel 2011).
Stock Assessments: General Fisheries Commission for the Mediterranean
All assessed stocks are considered over-fished, growth of over-fishing is a persistent issue and recommendations for dramatic reductions in effort are unlikely to be met. In the 1970s, this species ranked fifth in relative abundance along the Catalonian coasts, accounting for roughly 1.1% of the cumulative composition of species. In the same region, from the 1980s to 2007, this species was not among the top 10 most abundant species (Cartes et al. 2013).
In the Levant Sea, the first signs of over-exploitation of this species were detected during the 1950s (Aasen and Akyüz 1956, Akyüz 1957), before it became an explicitly targeted species in the region. During the mid-1980s, M. merluccius gained commercial importance. Due to augmentation of fishing effort and explicit targeting of M. merluccius, landings continued to increase in the Levant Sea until 1998 which marked a dramatic and un-reversed decline in landings. Total Biomass indices, estimated based on basin-wide survey, peaked at 45 tonnes per km-2 in 1984. In 2007-2010, BI-total for the Levant sea was estimated at 0.28. A combination of factors including over-exploitation, variability in penetration of Atlantic waters into the Mediterranean, and the impact of exotic species (Erythrean Lizardfish Saurita undosquamis) has been evoked to explain the disappearance of M. merluccius from the Levant Sea (Gucu and Bingel 2010).
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Habitat and Ecology|
This is a demersal species, that is found usually between 70 and 370 m depth. In the Mediterranean Sea, it has been found from 30 to 1,000 m. In the Ligurian Sea the species was caught starting from 18 m depth (Relini et al. 1986). It lives close to the bottom during the day, but moves off-bottom at night. Adults feed mainly on fishes (small hakes, anchovies, pilchard, herrings, cod fishes, sardines and gadoid species) and squids. The young feed on crustaceans (especially euphausiids and amphipods). Currents, such as the Poleward Current in the Gulf of Biscay (Sanchez and Gil 2000) and the East Corsica current in the Lingurian Sea (Abella et al. 2008), determine the major nursery grounds of M. merluccius by producing meso-scale eddies which retain larvae and favourthe feeding behaviour of recruits (Gucu and Bingel 2011). High-productivity areas are important nursery grounds for hake throughout its range (Gucu and Bingel 2011).
Life History and Reproduction
Maximum length recorded is 140 cm (TL) for males and 100 cm for females (Cohen et al. 1990). The maximum age is 20 years (Muus and Nielsen 1999). Size at maturity is between 26-27 cm for the males and 26-40 cm for the females (Golani et al. 2006). In the Tyrrhenian sea, size at maturity is 35 cm for the females (Sbrana et al. 2007). Bouaziz (2002) found the size at maturity to be 30.6 cm for females and 21.3 cm for males. The average age of reproducing adults has been reported to be as low as 3.0-3.5 years based on average age of adults in catches and depending on the area (Bouaziz 1992), however, a generation length of 11.3 years was estimated for this species based on maximum age and average age of first maturity by the HELCOM Red listing Project. Therefore, generation length is estimated to be between 3.5 and 11 years, depending upon the area and method used for calculation. In the Mediterranean, the maximum recorded size is 91 cm TL and the length at maturity for females ranges from 26.5 cm to 42.5 cm TL, and for males ranges from 21.0 cm to 29.5 cm TL (Tsikliras and Stergiou 2014).
Adult fish of these species are mainly demersal, usually inhabiting depths between 70 and 370 m. Age of first maturity is reached during the seventh year for most females (57 cm) and during the fifth year for males (40 cm) for the Atlantic subpopulation. The main spawning grounds are in the southern portion of the range in the Bay of Biscay, mainly in the canyons and rocky bottoms of the shelf break area (Casey and Pererio 1995). Spawning generally occurs between April and December, with a peak between February and March (Sanchez and Gil 1999). Maximum egg abundance occurs around 200 m (Valdes et al. 1996). Depending on the direction of the sea current, the larva are either deposited in the nursery areas of the Bay of Biscay or swept further out to sea (Sanchez and Gil 1999). The deposition of larvae in nursery areas has a high correlation with successful recruitment of the species (Sanchez and Gil 1999).
In two months time, the eggs metamorphose into juveniles. During their juvenile phase, these fish demonstrate vertical migration, preferring the muddy bottoms during the day and feeding at shallower depths at night. Adults also leave the bottom at night but do not migrate nearly as close to the surface as juveniles (Sanchez and Gil 1999).
The number of migrants between the Bay of Biscay and the Celtic Sea calculated with the IAM was 62 individuals and with the SMM was 34 individuals. In addition, at least one locus revealed significantly different genotype distributions (Lundy et al. 1999). These results suggest that migration between these fishing grounds is restricted and therefore relevant to fisheries management. However, until the temporal stability of this limited rate of migration between stocks from the southern Bay of Biscay and the Celtic Sea can be genetically demonstrated, caution should be taken in the management of these areas (Lundy et al. 1999).
|Generation Length (years):||3.5-11|
|Use and Trade:||This is a species with high commercial importance in the Mediterranean. It is used fresh, dried or salted and frozen (Frimodt 1995).|
This is a species with high commercial importance in the Mediterranean. There is evidence to support that this species is over-exploited and that over-fishing is a major threat to the subpopulations.
The main fishing methods used catch this fish are trawls, fixed nets and seines. Bottom longline and set-net fisheries are targeting adults of this species in some areas (not in Turkish waters at present). Details of this fishing effort are only rarely available.
The European Hake is the most important demersal species in western European continental shelf fisheries (Casey and Pereiro 1995). For this reason it has been extensively studied, but some uncertainty still remains concerning both the population structure and the state of the stocks. Indeed, recent molecular studies have shown that the spatial pattern of hake subpopulations is more complex than previously thought, with possible roles for ecological and oceanographic factors in temporal variation of population genetic composition in the Bay of Biscay (Lundy et al. 1999). Moreover, hake stocks are generally considered over-exploited (Alheit and Pitcher 1995). In 1955, over 160,000 tonnes were harvested; more recently, in 2000, approximately 60,000 tonnes were harvested, but in 2009 and 2010, nearly 100,000 tonnes were hauled in each year and sold on the market (FAO Fishery Statistics). According to the annual harvesting of this species, the species may seem to be relatively abundant. However, signs of overfishing could be dramatically reducing its numbers (FAO Fisheries and Aquaculture Department).
The number of migrants between the Bay of Biscay and the Celtic Sea calculated with the IAM was 62 individuals and with the SMM was 34 individuals. In addition, at least one locus revealed significantly different genotype distributions (Lundy et al. 1999). These results suggest that migration between these fishing grounds is restricted and therefore relevant to fisheries management. However, until the temporal stability of this limited rate of migration between stocks from the southern Bay of Biscay and the Celtic Sea can be genetically demonstrated, caution should be taken in the management of these areas (Lundy et al. 1999). Furthermore, high dispersive capabilities of a marine organism do not necessarily translate into high levels of realized gene flow. Population structure often does exist in such species (Palumbi 1994) and in these cases the evolutionary and ecological processes responsible nearly always have direct relevance to any management plans for exploited species involved (Avise 1998). By identifying genetically meaningful units, the management of economically important marine species can be improved by targeting individual units, or stocks with definable levels of recruitment and mortality (Lundy et al. 1999).
Merluccius merluccius is a priority species for the General Fisheries Commission for the Mediterranean (GFCM). It is regulated through fishing effort controls, selectivity, fishing closures, minimum landing size, etc. in the GSAs. There are also some national regulations regarding minimum landing size (e.g., in Turkey, minimum landing size is 25 cm, in Morocco minimum size is 20 cm) and an EC regulation for minimum landing size of 20 cm. It occurs in some marine protected areas. This species has undergone regional Red List Assessment in the Mediterranean (VU; Abdul Malak et al. 2011), the Baltic Sea (NT), and the Eastern Central Atlantic (LC).
Recommendations for this species are: implementation of GFCM recommendations (fishing effort controls, selectivity, fishing closures, minimum landing size, etc.) and improved enforcement of fishing controls in the Mediterranean Sea.
|Citation:||Fernandes, P., Cook, R., Florin, A.-B., Lorance, P. & Nedreaas, K. 2016. Merluccius merluccius. The IUCN Red List of Threatened Species 2016: e.T198562A84946555.Downloaded on 15 October 2018.|
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