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:
Identification:
The longnose stingray has a (slightly
wider than long) rhomboid disc with
a well produced snout, roughly straight anterior margins, obtusely
angular free tips and convex posterior margins. The dorsal surface
of the body disc is olive-grey to brown, usually with no obvious
markings but sometimes with darker spots. A row of tubercles
(enlarged dermal denticles) runs along the midline from behind eyes
to the base of the tail. Ventral surface pale/white or yellowish. Tail
long with a long, fleshy dorsal keel and a low ventral finfold.
Usually one but sometimes multiple spines present on tail. Tail
terminates in a long thin filament.
Size:
Maximum length 2m.
More commonly 1.25m.
Habitat:
Found in shallow bays on the sand from 1m down to 36m.
Sometimes adjacent to reefs. May move into brackish environments
such as estuaries.
Distribution:
Confined to the tropical Western Atlantic
from the southern Gulf of Mexico southwards to Santos, Brazil.
Diet:
The longnose stingray feeds mainly on benthic
invertebrates including crustaceans, mollusks, echinoderms (sea
cucumbers) and worms. Will also eat small fishes.
Reproduction:
Ovoviviparous. Litter size 1-2. Gestation
lasts approximately 5-6 months.
Conservation Status:
Listed as 'Data Deficient by the IUCN.
This is the most common ray species in artisanal fisheries in some
states of Northeastern Brazil (Maranhão and Paraíba). Also taken as
bycatch in shrimp trawls (Ceará) and a targeted species of sports
surf fisheries (Paraíba). For some states, such as Ceará, Paraíba
and Bahia, there are increasing fishing pressures on the species,
but no population assessments based on these fisheries. Monitoring
of artisanal fisheries directed towards this species, protection of
breeding and nursery grounds, population studies and more
information from its range outside Brazil are all required before
the conservation status of the species can be accurately assessed.
Photographs:
Gulf of Guatemala, Livingston, Guatemala, Caribbean
Sea.
Reaction to divers:
Skittish. Not easily approached.
Diving Logistics:
Although this ray is quite common along the east coast of Central America,
it is not particularly easy to track down due to the lack of coastal
dive shops on the mainland. Likely seen by coastal dive shops in
Guatemala and Honduras.
A known nursery area for longnose stingrays occurs
off the beaches of Caiçara do Norte in northeastern Brazil, where
newborns and small juveniles have been reported from water no more
than 3 m (9.8 ft) deep from February to October.
References and Citations:
Yokota, L. and R.P. Lessa (March 2006). "A
nursery area for sharks and rays in northeastern Brazil".
Environmental Biology of Fishes 75 (3): 349360.
Thorson, T.B. (1983). "Observations on the
morphology, ecology and life history of the euryhaline stingray,
Dasyatis guttata (Bloch and Schneider) 1801". Acta Biologica
Venezuelica 11 (4): 95126.
Rosa, R.S. & Furtado, M. 2004. Dasyatis guttata.
The IUCN Red List of Threatened Species 2004: e.T44592A10911036.
http://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T44592A10911036.en.
