|Scientific Name:||Myliobatis aquila (Linnaeus, 1758)|
Raja aquila Linnaeus, 1758
|Taxonomic Source(s):||Eschmeyer, W.N., Fricke, R. and Van der Laan, R. (eds). 2016. Catalog of Fishes: genera, species, references. Updated 29 September 2016. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (Accessed: 29 September 2016).|
|Taxonomic Notes:||It is unclear whether this, or a similar, species occurs along the east and west African coasts and Mediterranean Sea. A systematic review of this species is needed in these areas.|
|Red List Category & Criteria:||Vulnerable A2b (Regional assessment) ver 3.1|
|Assessor(s):||Serena, F., Holtzhausen, J., Ebert, D.A. & Mancusi, C.|
|Reviewer(s):||Jung, A. & Allen, D.J.|
|Contributor(s):||Buscher, E. & Fordham, S.|
|Facilitator/Compiler(s):||Dulvy, N.K. & Walls, R.H.L.|
Mediterranean regional assessment: Vulnerable (VU)
The Common Eagle Ray (Myliobatis aquila) is a semi-pelagic ray that occurs throughout coastal waters (<50 m) of the Mediterranean Sea, but is also known to dive deeper offshore to >500 m depth. In the northwest Mediterranean Sea, data from landings and trawl surveys showed that catches declined between 1970 and 1995, and the species became absent from catches and landings altogether in the late 1970s. In northern Mediterranean Sea trawl surveys from 1994–99 it was recorded in very low numbers. Few data are currently available to assess trends in other areas of the Mediterranean Sea, but given that fishing pressure is high throughout its bathymetric range there, declines are also likely to have occurred elsewhere. The Common Eagle Ray is suspected to have declined by at least 30% over three generations (33 years) in the Mediterranean Sea, and is therefore assessed regionally as Vulnerable under Criterion A2b.
|Range Description:||The Common Eagle Ray ranges throughout continental shelf and offshore waters of the Mediterranean Sea (Serena 2005). Outside the Mediterranean Sea, its range extends throughout the eastern Atlantic Ocean to the Indian Ocean.|
Native:Albania; Algeria; Bosnia and Herzegovina; Croatia; Cyprus; Egypt (Egypt (African part), Sinai); France (Corsica, France (mainland)); Gibraltar; Greece (East Aegean Is., Greece (mainland), Kriti); Israel; Italy (Italy (mainland), Sardegna, Sicilia); Lebanon; Libya; Malta; Montenegro; Morocco; Palestinian Territory, Occupied; Slovenia; Spain (Baleares, Spain (mainland), Spanish North African Territories); Syrian Arab Republic; Tunisia; Turkey (Turkey-in-Asia, Turkey-in-Europe)
|FAO Marine Fishing Areas:|
Mediterranean and Black Sea
|Population:||Landings data from the Gulf of Lions, France, and the northwest Mediterranean Sea from 1970–95, and data from a bottom trawl survey from 1957–95, showed a clear decrease in catches. This decrease, which was likely related to increased fishing effort, led to a total absence of the Common Eagle Ray from catches and landings after the late 1970s (Aldebert 1997). The International Trawl Survey in the Mediterranean (MEDITS) collected catch data from 1994–99 at depths of 10–800 m. This species was captured in 37 of 6,336 scientific survey hauls conducted throughout the northern Mediterranean during this period (Baino et al. 2001). Consequently, the population is estimated to be declining in these waters. Considering the evidence for local extinctions throughout its Mediterranean range, it is suspected that this species has declined by at least 30% over three generations (33 years).|
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
This semi-pelagic ray is found both inshore and offshore. It appears to primarily occur in inshore, coastal areas such as shallow lagoons and estuaries at depths of <50 m, although it has been reported from depths of up to 537 m (Whitehead et al. 1984). In the Mediterranean Sea this ray occurs on sandy and muddy substrates to 200 m depth (Notarbartolo di Sciara and Bianchi 1998, Serena 2005). It can often be found in groups swimming close to the bottom, and abundances appear to vary by season. In the Adriatic Sea, significantly higher abundances occurred in the summer at a depth range of 10–50 m compared to 50–100 m, while in the autumn no significant difference in abundance by depth was found to occur (Manfredi et al. 2010). Seasonal changes in range were also observed, with a narrower range in the summer (limited to the northern Adriatic and Croatian waters) and a wider range in the autumn (extended to the central Adriatic Sea; Manfredi et al. 2010).
The Common Eagle Ray is live bearing with yolk sac (Whitehead et al. 1984). In the Mediterranean Sea, females give birth to between three and seven pups per litter, after a gestation period of six to eight months (Whitehead et al. 1984, Fischer et al. 1987, Serena 2005). Females mature at 60 cm disc width (DW) and males at 40 cm DW (Fischer et al. 1987, Serena 2005). Reproduction takes place between September and February (Notarbartolo di Sciara and Bianchi 1998). The species reaches a maximum size of 150 cm DW and 260 cm total length (Fischer et al. 1987, Notarbartolo di Sciara and Bianchi 1998). Generation length is inferred from a similar batoid as approximately 11 years.
|Generation Length (years):||11|
|Movement patterns:||Full Migrant|
|Use and Trade:||There is no information available on the use or trade of this species from the Mediterranean region.|
The Common Eagle Ray is taken as bycatch in various commercial and artisanal fishing gears throughout its Mediterranean range, such as bottom trawls, purse seines, gillnets, and line gear. The schooling behaviour of this species means that large numbers could be fished out in one haul (Ebert and Stehmann 2013)
Fisheries have increased in both effort and capacity in the Mediterranean Sea in recent decades (Aldebert 1997). The continental shelf and upper slope of the Mediterranean Sea are exploited heavily to a depth of 800 m, much of which is within this species’ bathymetric range (Massutí and Moranta 2003). An experimental trawl fishery in the Aegean Sea revealed that this eagle ray was one of the more prevalent non-commercial species, representing up to 5.9% of the total catch weight during the summer months and 4.3% in the autumn (Gurbet et al. 2013).
There are no species-specific conservation or management measures in place in the Mediterranean Sea.
|Citation:||Serena, F., Holtzhausen, J., Ebert, D.A. & Mancusi, C. 2016. Myliobatis aquila. The IUCN Red List of Threatened Species 2016: e.T161569A16527996.Downloaded on 22 June 2018.|
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