Pacific Eagle Ray, Spotted Eagle Ray.
A large ray with a rhomboidal disc that is significantly wider than long. Large, protruding head with a moderately long, parabolic rostral lobe. Spiracles large. Mouth narrower than pre-oral (rostral lobe) length. Nasal curtain large, with a fringed posterior margin and deep central notch. Powerful pectoral fins have straight anterior margins, concave posterior margins, and falcate, pointed apexes. Pectoral fin origin level with eyes. Dorsal fin small, with a broadly rounded apex. Disc entirely smooth; lacking thorns. Tail filamentous and long when intact. One or more tail spines present.
Dorsum slate grey, blue-grey, or almost black, with numerous small white spots or rings. Tail unmarked. Ventrum white.
Max. disc width at least 230cm but usually less than 130cm.
Tropical/subtropical seas. Sandy bays, coral reefs, and rocky outcrops. Sometimes in brackish estuaries. Often seen swimming close to the substrate, but also occurs in midwater and sometimes near the surface. Intertidal to at least 30m depth (personal observation) and probably much deeper.
Previously thought to be a regional variant of a the spotted eagle ray but the latter has recently been split into at least three regional species. A. laticeps is now considered an eastern Pacific endemic, occurring along the west coast of the Americas from the Sea of Cortez to the Galapagos Islands.
The spotted eagle ray complex is listed as NEAR THREATENED by the IUCN. However, this assessment is based on the incorrect assumption that there is only one globally occurring species.
Spotted eagle rays in the eastern Pacific are regularly caught (and retained) in gill net fisheries throughout Mexico and Central America. Therefore, once the recent splits are reassessed, the combination of fishing pressure and the limited range of the Pacific eagle ray, may warrant a vulnerable or endangered designation.
Kyne, P.M., Ishihara, H, Dudley, S.F.J. & White, W.T. 2006. Aetobatus narinari. The IUCN Red List of Threatened Species 2006: e.T39415A10231645. https://dx.doi.org/10.2305/IUCN.UK.2006.RLTS.T39415A10231645.en. Downloaded on 25 January 2021.
Matrotrophic viviparity. Litter size unknown.
Diet consists mainly of bivalves, but also consumes polychaetes, shrimps, and small fishes.
May be found solitary or in large schools. Excavates deep holes in the sand to capture benthic invertebrates.
Reaction to divers
Usually shy around scuba divers. May be more approachable when digging for food.
Pacific eagle rays are quite easy to find along the Pacific coast of Costa Rica and Panama. I have encountered them at numerous sites including Isla Catalina and Montezuma in CR, and Isla Iguana and Coiba in Panama.
They are also spotted very regularly at Cocos Island, Malpelo Island, and around the Galapagos Islands. At Malpelo in particular, I have seen them forming small schools of 10-20 animals.
After more than a dozen trips to Socorro, I have yet to see one there so although they are listed as occurring in the Sea of Cortez, they are clearly uncommon this far north.