Marine miracle ray dies, DNA tests done

THE first bull-nose ray pup born at ushaka Sea World Aquarium by a female that had not been in contact with a male bull ray in a decade, has died.

The South African Association for Marine Biological Research, whose mandate is to stimulate community awareness of the marine environment, suspects that the two-week-old pup was born through a process called parthenogenesis.

This has been described as a natural form of asexual reproduction in which growth and development of embryos occur without fertilisation by sperm. It is a mode of reproduction known to occur among a number of plant and animal species, including some sharks.

However, there was no prior recorded evidence of the process having occurred in bull rays.

The association’s Ann Kunz said parthenogenesis was sometimes seen as a survival strategy by females in the absence of males of their species.

“Our pup was a female and this is also typical of pups born by this process,” she said.

Kunz said bull rays, also known as bull-nose rays or duckbill rays, had a long fleshy snout similar in appearance to a duck’s bill. This particular species has pale blue-grey bars on their backs and can grow to more than 100kg and a 2m wide.

She told the Sunday Tribune that the pup, born on May 4, was discovered swimming in the open ocean exhibit at ushaka Sea World.

“This was the first time that a pup of this species has been born to one of our three resident female bull rays,” she said.

“All three of the adult females in the exhibit have been there for the past 10 years with no male bull ray present during this time.

“We don’t have any males here,” Kunz said.

When the pup died on Tuesday, scientists were busy conducting DNA tests to determine whether or not the pup was a hybrid, where the female might have mated with one of the other ray species in the exhibit. It was being kept and monitored in a quarantine facility.

The pup had grown to a size slightly bigger than a man’s hand when it was found dead by a staff member.

“It was in perfect condition, it looked perfect with no visible abnormalities. It was a perfect replica of the adult.

“We did a post mortem and took samples that we needed. We will keep it until we are satisfied that we have all the genetic material that we need and then it will be incinerated,” she said.

Kunz said they were expecting to get the results from the lab within two weeks, and that they would be sharing these with all interested parties.