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:
Brown Stingray, Roughtail
stingray, Roughtail ray,
Rough-tailed stingray.
Latin Name: Bathytoshia
lata.
Synonyms: Dasyatis centroura
Family: Dasyatidae
Identification:
An enormous stingray.
Rhomboid disc with rounded pectoral tips and straight leading edges. Tip of
snout protruding. Thorns
scattered on midline of back and prominent thorns along midline and sides of
tail. Tail approx twice disc width with long, low ventral finfold. Dorsum grey/brown
to olive brown, sometimes blackish. Ventrum pale.
Size: Maximum
disc width 260cm. Usually 100 to 130cm. At birth 35cm.
Habitat: Sand
and mud bottoms from intertidal to 800m. Inhabits coastal areas, estuaries, and
rivers.
Distribution:
Western Atlantic - Georges Bank to Florida, Gulf of
Mexico, and Uruguay to Southern Brazil. Subtropical; 45°N - 35°S, 90°W -
36°E.
Diet:
Preys on crabs, prawns and small bony fishes.
Reproduction:
Ovoviviparous.
Conservation Status:
The IUCN lists the Brown
Stingray Bathytoshia lata as LEAST CONCERN. However, the assessment is out of date and
still refers to populations on both sides of the Atlantic. Consequently, the
following information should not be relied upon to determine policy.
In the Mediterranean
this stingray is taken as bycatch of the artisanal fisheries, bottom set
longline, gillnet and handline (Fischer et al. 1987). Benthic trawl effort has
increased both effort and efficiency in the shelf and slope areas of the
Mediterranean Sea over the last 50 years. The continental shelf and upper slope
of the Mediterranean Sea are highly exploited, with intensive commercial
trawling occurring at depths ranging from 50 to 700-800 m (Colloca et al. 2003,
Massuti and Moranta 2003). As a result there has been increasing concern about
changes in the abundance and diversity of elasmobranchs in this region, and
decreases in the abundance and biomass of some species throughout the last
decade have been reported in highly exploited areas such as the Gulf of Lions (Aldebert
1997, Massuti and Moranta 2003). Although no species specific data are
available, the very large size of D. centroura makes it intrinsically vulnerable
to population depletion. Given that this species is rarely captured in the
Mediterranean, high exploitation of the continental shelf, its intrinsic
vulnerability and evidence for declines where data are available in other
elasmobranch species within this region, it is suspected to have declined.
Photographs: Los
Gigantes, Tenerife, Canary Islands, North West Africa.
Similar species: In the western
Atlantic, there is a closely related Roughtail Stingray - Bathytoshia
centroura. This ray was recently split from Bathytoshia lata but
further analysis may recombine these species.
Reaction to divers:
May be approached with non threatening movements.
Diving logistics:
Los Gigantes on Tenerife is the place to encounter this species. Los Gigantes
Dive Centre runs feeds twice weekly that attract up to six species of rays
usually including this one.
Citations:
Ebert, D.A., Vidthayanon, D.A. &
Samiengo, B. 2016. Bathytoshia lata. The IUCN Red List of Threatened Species
2016: e.T161386A104066775. http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T161386A104066775.en.
Downloaded on 23 October 2017.