Common Eagle Ray: Myliobatis aquila

Family: Myliobatidae
Common name(s)

Common Eagle Ray, Eagle ray, Bull Ray.

Identification

A medium-sized ray with a kite-shaped disc (approximately 2x wider than long) and large protruding head with a short, fleshy, broadly rounded rostral lobe. Males have small, horn-like knobs above eyes. Spiracles large, positioned laterally, not visible from above. Nasal curtain short and wide with a long fringe along posterior margin, without deep central notch.
Pectoral fins have straight anterior margins, mildly concave posterior margins, and narrowly rounded apices. Pectoral fins originate below eye. Disc entirely smooth, lacking denticles or thorns. Pelvic fins large, extending well beyond disc margin. One small dorsal fin with a broadly rounded apex and a short free rear tip, positioned anteriorly to caudal sting. Tail broad based and long, tapering to caudal sting then filamentous to tip. Tail length 2-2.5 x disc width when intact. One or two long caudal stings usually present.

Colour

Dorsum beige to dark purplish brown without markings. Ventrum white, sometimes with a dark margin posteriorly.

Size

Maximum disc width 150cm. Southern populations are significantly smaller, reaching a maximum DW of around 80cm. Disc width at birth up to 19cm.

Habitat

Tropical and temperate seas. Prefers shallow sandy or muddy bays, estuaries, and lagoons. Usually less than 50m but recorded at 537m in Southern Africa.

Distribution

Eastern Atlantic, Mediterranean, and southwest Indian Ocean. Widespread in southern Europe and around much of the African continent. From southern England to Kenya, including the Canary Islands and Madeira. The common eagle ray is more common in the southern part of its range, having been depleted by decades of overfishing in the Mediterranean.

Conservation Status

DATA DEFICIENT

Common eagle ray populations in Europe may differ from populations elsewhere and a systematic review of the species in these areas is required. Common Eagle Ray appears to be less common in the Mediterranean Sea and possibly the eastern Atlantic. Time series data from demersal fishery landings and demersal trawl surveys show that this species declined in the Gulf of Lions, northwestern Mediterranean Sea, in the late1970s. It was recorded in low numbers during northern Mediterranean-wide trawl surveys from 1994–1999, and is still sometimes observed on fish markets. Few data are currently available to assess trends in other areas of the Mediterranean Sea, but given that fishing pressure is high throughout this species’ bathymetric range there, declines are also likely to have occurred elsewhere. This species is assessed as Near Threatened in the Mediterranean Sea. Further investigation of catch trends in the southern Mediterranean is required and with further information this species may prove to meet the criteria for Vulnerable A2bd+A3bd. No data are currently available from the eastern central Atlantic, but this species is presumably taken in coastal artisanal fisheries along the coast of western Africa and investigation of the species’ status in this area is a priority. Off southern Africa, it only rarely taken as bycatch and is not subjected to great fishing mortality. Available time series data on catches of this species from 1981–2001 showed no trend, and the species is assessed as Least Concern in southern Africa. The lack of data on catches and population trends throughout the species’ range and uncertain taxonomic status of populations in Europe and southern Africa precludes a global assessment beyond Data Deficient at present. This assessment should be revisited when these issues are better resolved.

Citation

Holtzhausen, J.A., Ebert, D.A., Serena, F. & Mancusi, C. 2009. Myliobatis aquilaThe IUCN Red List of Threatened Species 2009: e.T161569A5454004. https://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T161569A5454004.en. Downloaded on 06 March 2021.

Reproduction

Matrotrophic viviparity. 3-7 pups per litter. Gestation 6-8 months.

Diet

Diet consists mainly of invertebrates including crabs, bivalves, and polychaete worms. Plus small demersal fishes. Destructive to aquaculture.

Behavior

Found solitary or in small groups, usually close to the substrate.

Reaction to divers

Usually shy around scuba divers unless bait is introduced.

Diving logistics

Common eagle rays are fairly easy to encounter in southern Africa but the best place for observing this species is at Los Gigantes on Tenerife in the Canary Islands. Los Gigantes Dive Centre organizes a stingray feed that attracts a variety of rays including this species.

In South Africa, I was able to photograph this species with a baited remote camera deployed in approximately 50m off East London.

Similar species

Duckbill Eagle Ray Distinguished by narrower rostral lobe and subtle banding on dorsum.