Birth of Black blotched fantail rays at S.E.A. Aquarium

S.E.A. Aquarium is pleased to announce the birth of seven Black blotched fantail rays- the largest litter to date.

Both mother and pups are doing well under the care of our Aquarist and Animal Health teams, who are monitoring their growth and development. The birth of these adorable stingray pups is cause for celebration as Black blotched fantail rays are at high risk of becoming endangered in the wild.

Juvenile Black blotched fantail rays at 3 weeks old.

To better protect these rays it is essential to have a good understanding of their life history. With the Black blotched fantail rays there is still a lot to learn.

  • What age do they mature?
  • How long do females carry their young?
  • How often do they reproduce?

We are using this remarkable opportunity to gather as much information as possible, to help better understand these captivating animals.

Learn about the Black blotched fantail ray

Adult Black blotched fantail ray resting in the Open Ocean Habitat.

The Black blotched fantail ray (Taeniura meyeni) is a large stingray, which is widely distributed in the Indo-West Pacific. They are disc-shaped and known to measure up to 180cm in length (excluding their tails!), that’s longer than the height of an average male Singaporean!

The name Black blotched comes from the mottled pattern of black, grey and white spots and blotches on their upper surface. Their tails are prominent with a skin fold that extends to the tip of the tail.

The hump shows that this is a pregnant female Black blotched fantail ray.

Pregnant female Black blotched fantail ray.

S.E.A. Aquarium is home to 10 adult Black blotched fantail rays in the Open Ocean Habitat. Breeding occurs naturally, and from our observations the female will carry her young for approximately six to eight months.

Like most animals, it is easy to tell when a ray is pregnant as she gets a lot larger in size. Litter sizes typically average between three to four pups, but a maximum of seven young has been reported for this species.

The Aquarists and Animal Health team will look for signs of pregnancy by observing mating behaviour, conducting ultrasounds and running blood tests to confirm the pregnancy. The female will be monitored as time passes and she will be moved into a special holding area closer to the time of delivery.

The Animal Health and Aquarist teams conducting an ultrasound on a female Black blotched fantail ray.

The teams will conduct ultrasound scans to monitor the development of the young. From the ultrasounds we can see the pups’ development, and even estimate how many pups she will deliver.

To perform the ultrasound, the female ray is carefully lifted just below the surface of the water. These rays may look elegant and graceful in the water but an adult female can weigh up to 150kg before pregnancy- almost three times the weight of an average person.

How Black blotched fantail ray develops inside its mother

Ultrasound of a developing Black blotched fantail ray.

The young develop from egg to juvenile inside the mother and she gives birth to live young.

The mother and pups are not connected in her uterus- this is known as ovoviviparity. Instead the unborn young feed initially on a yolk, but they also receive additional nourishment by absorbing nutritious fluids from their mother. This advanced system of feeding young inside the uterus can produce offspring that are relatively large at birth, who are able to feed and fend for themselves much like an adult. Unlike marine mammals the mothers do not care for the young once born.

Inside the mother the pups are rolled up like a spring-rolls! The pups remain this way until the female gives birth, at which point the young rays will unroll and swim away. The pups are also born with their stings in place! The sting has a protective gelatinous sheath, which protects the mother whilst giving birth.

Taking care of Black blotched pups

Juvenile Black blotched fantail rays have a prominent white lining around their circumference which fades as they get older.

Newborn Black blotched pups are born with creases along their wings as they have been rolled up inside the mother. They also have a prominent white lining along the rim of their circumference. They are born with the black spots, and retain these spots but become less defined and more ‘smudged’ in their adult stages.

The Aquarists are feeding the newborns a rich diet of cut prawns, fish and squids to ensure they get the energy they need for growth. At S.E.A. Aquarium we have created nursery habitats for our young rays, which allow us to monitor their growth and development. Born at a disc size of 20-30cm they have a long way to go to reach their adult size!

Throughout Southeast Asia there is significant fishing pressure on large rays, and whether targeted by fishermen or accidentally caught (known as bycatch), all are taken and utilized in some form. As bottom dwellers, they are often caught in prawn and fish trawlers that run along the sea floor.

Many fisheries are now taking steps to prevent stingrays from being caught, by creating escape hatches so they can escape the nets. The more we learn about the life history of these Black blotched fan tail rays, the more we can do to protect them.

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