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Megamouth shark mystery solved as pregnant animal washes up on beach

1. The megamouth shark examination team consisted of Dr. AA Yaptinchay, Elson Aca, and staff from the National Museum of the Philippines- Zoology Division. (Courtesy of the National Museum of the Philippines)
1. The megamouth shark examination team consisted of Dr. AA Yaptinchay, Elson Aca, and staff from the National Museum of the Philippines- Zoology Division. (Courtesy of the National Museum of the Philippines)

Scientists made a remarkable discovery after a megamouth shark washed up on the shores of Aurora, Philippines last month.

The 18-foot shark was found to be recently pregnant with seven pups, who looked to have been expelled from her body on the shore, confirming to scientists for the first time that the elusive creatures give birth to their offspring instead of laying eggs.

Little is known about the mysterious megamouth shark, as it was only discovered and recorded in 1976, and only around 100 of them have been observed, usually when they have been accidentally caught or stranded.

“This first record of a pregnant megamouth shark in Aurora Philippines paves the way for more research, particularly in understanding the species’ biology, especially during its developmental stages,” a spokesperson from the National Museum of the Philippines told The Independent.

The mother shark was found on 14 November and was taken in for a necropsy performed by an expert from the Philippines’ Bureau of Fisheries and Aquatic Resources, the National Museum of the Philippines announced on their Facebook page.

One of the pups also underwent a necropsy, while the six remaining pups were taken to the museum for further examinations and processing, such as genetic testing to see if the young could have different fathers.

After the examinations are finished, the sea creatures will be kept at the museum and preserved in their collection for future exhibitions.

The examination of the 6 megamouth shark pups was conducted at the National Museum of the Philippines. The results open to further study and research on this species. (Courtesy of National Museum of the Philippines)
The examination of the 6 megamouth shark pups was conducted at the National Museum of the Philippines. The results open to further study and research on this species. (Courtesy of National Museum of the Philippines)

The find is significant because it is the world’s first record of a pregnant megamouth shark.

Researchers were previously unsure if the megamouth shark could be ovoviviparous like other shark species, meaning eggs develop inside their body, which they later lay.

The pups could have possibly been birthed on the shore due to the stress of capture or accidentally beaching itself, as similar situations cause other shark species to expel their pups or eggs, AA Yaptinchay, a researcher involved in the necropsy, told New Scientist.

There were no signs of injuries caused by fishing equipment on the shark, meaning it couldn’t have been caught, but it is still unclear how the shark became stranded, Yaptinchay said.

Tissue samples were collected from the 6 megamouth shark pups. The examination was led by Dr. Yaptinchay and Elson Aca. (Courtesy of the National Museum of the Philippines)
Tissue samples were collected from the 6 megamouth shark pups. The examination was led by Dr. Yaptinchay and Elson Aca. (Courtesy of the National Museum of the Philippines)

Her pups measured a lengthy 165 to 183.5 centimetres long, but Mr Yaptinchay told the outlet that it was concerning from a conservationist standpoint that the shark produces very few offspring.

“Now we know they just have seven pups, compared to whale sharks, which have over 300 or tuna, which have millions,” he said.

The megamouth shark is one of three ‘filter feeder’ sharks known to exist, using their distinctive large and wide mouths (hence the name) to capture prey as they swim along.

The waters surrounding the Philippines are the second-most populated megamouth shark habitats, as Taiwan is thought to have more reports and sightings of the enigmatic creature.