learn only 3 things about them ...
They are related to sharks and have cartilage instead
They swim by undulating greatly enlarged pectoral fins.
will not sting unless you handle them or step on them.
Watch your step!
strange 'flying' saucers with bulbous eyes and long whip-like tails,
these fishes are often seen in our mangroves and coral reefs. They
can sting painfully! These fishes often hide in silty bottoms and
under coral ledges, watch where you step and where you put your hand.
What are stingrays? Stingrays
belong to the Family Dasyatidae. According to FishBase:
the family has 9 genera and 70 species. Together with skates and rays,
stingrays belong to the Order Rajiformes. These fishes are related
to sharks but most are adapted for hunting and living on the sea bottom.
They have flattened bodies with enlarged pectoral fins.
Features: The largest species
of stingrays can grow to 4m in diameter. Those commonly seen on our
shores are much smaller.
Like other rays, stingrays have greatly enlarged pectoral fins along
their body edges. With graceful undulations of these fins, they seem
to ‘fly’ through the water. They generally swim slowly, but can make
a quick dash if they need to. They also flap the enlarged fins to
bury themselves in the sand in an eyeblink. Stingrays have no or indistinct
dorsal fins. They have long whip-like tails but lack tail fins. Their
bulbous eyes stick out above the flat body, allowing them to peer
out when they lie buried in the sand.
Living close to the silty or sandy bottom, stingrays have a different
way of taking in water to breathe. To avoid sucking in mud and sand,
water is taken in from the upperside of the body through holes called
spiracles. These holes are found just beside their eyes. The water
is then expelled through five pairs of gill slits on the underside
of the body.
Rays are closely related to sharks. Like sharks, the skeleton of a
stingray is made of flexible cartilage. If you want to know how cartilage
feels like, your nose and ears are made of cartilage! The stingray's
flat teeth are also made of cartilage but are strong enough to crush
clam shells. This is because the teeth are stiffened and braced with
struts of different types of cartilage.
Most stingrays have one spine (some may have up to four spines), often
near the base of the tail (where the tail joins the body). Stingrays
don't sting with the tip of the tail. These spines are serrated and
can cut deeply and introduce venom into the wound that can cause excruciating
pain. These spines are used to protect themselves and not to hunt
prey. They can replace lost spines.
Sometimes mistaken for a horseshoe
crab and visa versa. In murky waters, these two different animals
do have a similar profile, both being round and flat with a long tail.
Other similarly shaped fish include the Electric
ray (Narcine sp.).
ray! Stingrays are not aggressive animals
and prefer to flee from danger. Most stingray injuries
are the result of carelessness, generally when someone
accidentally steps on a stingray that is lying harmlessly
on the bottom. Stingray spines can penetrate through booties!
How to stay safe: Wear
covered shoes. Watch your step and walk slowly. Be aware
of your steps, if you feel a movement under your foot,
pull back and don't step down with your full body weight.
Do not step into murky water.
What do they eat? Most rays are
well adapted for bottom-dwelling. Their flattened body allows them
to hover close over the bottom like a vacuum cleaner. The mouth is
on the underside to forage for buried bivalves, crabs and worms. These
are crushed and ground up with blunt teeth.
How do they hunt for prey? The
snout may function as an electroreceptive organ, sensitive to electric
charges of prey buried in the ground. Once they find signs of an edible
titbit in the sand, they may expose the buried prey by blowing a jet
of water from the mouth. They may also flap their enlarged pectoral
fins to dig up large shallow holes in sand or mud. On some of our
shores such as Chek Jawa, such 'craters' are often seen on the sand
Baby rays: Stingrays practice
internal fertilisation. Males have a pair of claspers near the pelvic
fins with grooves to introduce the sperm into the female. Stingrays
give birth to live, fully developed young.
Human uses: Stingrays are
a popular seafood dish in Singapore. The large pectoral fins are barbequed
and served with chilli, often on a banana leaf. You can see their
cartilageous bones as you eat the flesh. The Blue-spotted
fantail ray (Taeniura lymma) is also popular in the live
aquarium trade although it does not do well in captivity.
Status and threats: Our stingrays
are not listed as endangered. However, throughout its range, the Blue-spotted
fantail ray (Taeniura lymma) is under pressure from over
collection for the aquarium trade and destruction of its reef habitat.
Like other creatures of the intertidal zone, Stingrays are also affected
by human activities such as reclamation and pollution. Over-collection
by hobbyists and fishermen can also have an impact on local populations.
Spiracles on the upperside behind the eyes.
Chek Jawa, Aug 02
Mouth and gill slits on the underside.
Pulau Sekudu, May 04
'Craters' left behind by feeding stingrays?
Chek Jawa, May 02
A gathering of Blue-spotted stingrays
and Mangrove whiprays.
Pulau Sekudu, Apr 06
An egg case laid by a shark or a ray.
Sentosa, Jun 08
This one was caught in a drif net.
Chek Jawa, Aug 02
on Singapore shores
Dasyatidae recorded for Singapore
Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity
*from Lim, Kelvin K. P. & Jeffrey K. Y. Low, 1998. A Guide to the
Common Marine Fishes of Singapore.
**from our observation.