Not just a
huge collection of
Shark
Pictures:
Elasmodiver.com contains images of sharks, skates, rays, and a few
chimaera's from around the world. Elasmodiver began as a simple web
based
shark
field guide
to help divers find the best places to encounter the different
species of sharks and rays that live in shallow water but it has
slowly evolved into a much larger project containing information on
all aspects of shark diving and shark photography.
There are
now more than 10,000 shark pictures and sections on shark
evolution, biology, and conservation. There is a large library of
reviewed shark books, a constantly updated shark taxonomy page, a
monster list of shark links, and deeper in the site there are
numerous articles and stories about shark encounters. Elasmodiver is
now so difficult to check for updates, that new information and
pictures are listed on an Elasmodiver Updates Page that can be
accessed here:
Family:
Aetobatidae. Containing the single genus 'aetobatis'. Recently elevated to full
family status. Previously considered part of the family myliobatidae.
Identification:
A large eagle ray with a greenish-grey or yellowish-brown dorsum
covered in white or bluish-white spots. Occasionally,
spots may take the form of small white rings with dark centers (ocelli). Disc rhomboidal, wing-like,
falcate.
Anterior disc margins straight becoming convex towards free rear tips. Posterior margins
of pectoral fins concave. Pectoral intersec with prominent square head at eye
level. Rostral lobe (snout) wide and moderately long (much wider than in
A.ocellatus). Caudal fins extend rearward beyond pectoral margin. Very long,
whip like tail. Tail length 1.8-2.3 times disc width when intact. 1 to 2 tail spines. Mouth located ventrally. Teeth
plate-like. Nasal curtain (upper lip) large, fringed and deeply notched
centrally.
Size:
Disc width to 230cm.
Habitat:
Coastal. Reefs, sand flats and shallow bays.
To at least 60m.
Distribution:
Tropical Western Atlantic including the
Gulf of Mexico and throughout the Caribbean Sea. Possibly also coastal, tropical
Eastern Atlantic.
Diet:
Feeds by
plowing its flattened snout through the
sand, scooping up buried invertebrates. Preys on Polychaete worms, bivalves,
gastropods, cephalopods, shrimps and small fishes.
Reproduction:
Ovoviviparous. Produces litters with up
to 4 pups.
Conservation Status:
the spotted eagle ray is listed as NEAR THREATENED by the IUCN.
However, this is based on the incorrect assessment that Aetobatus narinari is a
globally occurring species. The revised distibrution is far more limited (see
Distribution above). The Western Atlantic population probably faces a
considerably lower threat level. Whitespotted eagle ray populations in Florida
are completely protected, while populations within the Caribbean are not fished
commercially.
Eastern Atlantic
populations (if they are the same species) are probably under greater threat as
subsistence fishing is more prevalent and protection is non-existent.
Photographs:
Top image - Grand Cayman. Bottom image - Isla Mujeres.
Similar species:
Recent genetic, morphological and parasitic study
has split the spotted eagle ray into three distinct species that can be identified easily
by range. The spotted eagle ray Aetobatis ocellatus is present in the
Indo-West/Central Pacific region. The whitespotted eagle ray is confined to the
tropical Atlantic including the Gulf of Mexico and Caribbean Sea, and the
Pacific eagle ray inhabits the tropical Eastern Pacific coast and Galapagos
Islands.
Further studies may
eventually split the central and western populations of A.ocellatus into two
distinct species.
Reaction to divers:
Somewhat
shy and hard to approach. Easiest to approach when they are preoccupied with feeding.
Diving logistics:
Commonly encountered by scuba divers and
snorkellers in Florida, the Bahamas, Turks and Caicos and the Caribbean but
unpredictable. The C58 Wreck in Cancun reliably attracts large schools of
whitespotted eaglerays and can be dived year round. Visit
SoloBuceo.com for more
information.
Citations:
Kyne, P.M.,
Dudgeon, C.L., Ishihara, H., Dudley, S.F.J. & White, W.T. 2016. Aetobatus
ocellatus. The IUCN Red List of Threatened Species 2016:
e.T42566169A42566212. http://dx.doi.org/10.2305/IUCN.UK.2016-1.RLTS.T42566169A42566212.en.
Rays of the
World - Last, White, de Carvalho, Seret, Stehmann, and Naylor. CSIRO.