Not just Shark
Pictures: Elasmodiver contains photos of sharks, skates, rays, and
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
There are now
more than 5000 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:
disc, sometimes appearing teardrop shaped. Anterior disc margin concave.
Posterior margin and outer margins rounded. Pointed snout on a broad based
triangle. Tubercles on centre line of dorsum and first part of tail. Two short
parallel rows of tubercles behind eyes, roughly half way between eyes and
posterior disc margin. Tail thin, and long. Low dorsal and ventral finfolds
present on tail, especially thin in juveniles. Dorsum Brown or tan paling
towards margins where it may have a pinkish hue.
disc width 49cm.
and mud bottoms from intertidal to 20m. Inhabits coastal areas, estuaries, and
rivers. Capable of existing year round in freshwater environments.
Atlantic stingray is unique in North America in its ability to thrive in a fresh
water environment.In general, elasmobranches are considered to be
stenohaline (salinity restricted) marine species. The bull shark has been
reported many miles up rivers, but these forays eventually
end with its return to a saline environment. Although some populations of the
Atlantic stingrays are believed to remain year round in freshwater systems, they
have not lost their ability to return to the sea, as have their freshwater
cousins of South America. Rays of the family Potamotrygonidae which inhabit the
Amazon Basin have lost the ability to retain urea in their body fluids. This
minimizes the osmotic gradient related to a freshwater existence. The trade off
for the Atlantic stingray is that even in fresh water their kidneys reabsorb
urea. In fresh water, they still retain about 50% of their urea leading to a
total osmotic pressure that is 15 times greater than their environment. So these
animals face a very large osmotic uptake of water. To compensate for the influx
of water, these stingrays have a considerable urine flow rate which is almost 10
times higher than those found in marine individuals.
Abundance and distribution: From
Chesapeake Bay to the Gulf of Mexico. Most common in coastal habitats. St Johns
River system in Florida and adjacent springs has the only fresh water population
of any elasmobranch in North America. This ray has been found up the Mississippi
River as far as 320km.
holes in sand in search of Tube anemones, polychaete worms, crustaceans, clams,
and serpent stars.Faces into current to feed allowing sediment to be
Male often follows female with his snout close to her cloaca and nibbles and
bites her disc. Breading period from October to March. Gestation period April to
August. Gives birth from mid to late summer in Florida.
Andrews State Recreation Area, Panama City, Florida.
Similar species: Southern
stingray, Bluntnose stingray.
Reaction to divers: Easily
approached with non threatening movements.
The Atlantic Stingray can often be found at the Jetty at St. Andrews State Recreation Area at
Panama City. It is possible to snorkel with them or dive but I found them mainly
in the 8 to 15ft range, so tanks are not really necessary. Air fills can be
obtained from Panama City Dive Centre near the entrance to the park. Two options
are to dive the beach on the right side of the rock jetty or swim through the
sheltered swimming area and drop into the channel. Make sure you have an
incoming tide for clarity and to avoid being swept out into the bay. This is a
great area to find rays. On the same dives and snorkels I found Southern
stingrays and Bluntnose Stingrays. I also saw a school of around 25 Devil rays
but sadly I didnít have my camera when they showed up.
Other diving locations submitted by readers:
Peter Piermarini PhD. University of Florida -
The Atlantic stingray (web page).
Scott W Michael - Reef Sharks and Rays of the
Biglow, H.B. and William C. Schroeder. Ė Fishes of the Western North Atlantic Part
two. (Sears Foundation for Marine Research, Yale University. 1953).