Diver Spots One of the Atlantic Ocean's Rarest Shark Eggs

A fisherman has discovered a rare shark egg floating in the Atlantic Ocean off the Brazilian Coast, the second such find in the past month.

Erivaldo Alves Silva shared video of his find in the waters off the Fernando de Noronha archipelago, 220 miles from the Brazilian coast.

Silva was diving to catch octopi on Sept. 14 when he came across the unusual specimen, which he didn't recognize right away. His footage shows what appears to be an orange-colored pouch floating on the water.

"I have never seen such a thing in my life," he said. "At first I thought it was weird, but I didn't think it was that weird. Only after I posted it [online] did people say it was a rare find. A shark egg, according to biologists, is very rare."

Shark Egg found by diver
A Brazilian man found this shark egg in the Atlantic Ocean off the Brazilian coast during a dive. Nego Noronha/Zenger

Silva says he left his rare find in the sea.

His sighting was the second reported sighting of a shark egg in the waters off Fernando de Noronha in less than a month.

The egg belongs to a nurse shark, said fisheries engineer Leo Veras. The species is listed as vulnerable on the International Union for the Conservation of Nature's Red List of Endangered Species because of threats from human intrusions and disturbances. Recreation and both commercial and residential development have threatened the sharks' habitat.

Nurse sharks are about a foot long at birth but can grow to more than 10 feet long. They feed mostly on octopi, squids, stingrays, clams and marine crustaceans—not humans—according to the Florida Museum of Natural History.

Unlike some of their speedier counterparts, nurse sharks are slow and sedentary. Despite that, the nocturnal bottom-dwellers rank fourth in documented shark bites on humans, according to the Florida Museum.

The species reproduces every two years, Veras said. Each pregnancy can result in 20 to 30 offspring.

Shark Egg found in Brazil
The shark egg found in the sea in Fernando de Noronha in Brazil by surfer and fisherman Erivaldo Alves Silva. Nego Noronha/Zenger/Getty Images

Nurse sharks are one of the relatively few shark species that lay eggs; most give birth to live young the way mammals do. Shark eggs hatch while still inside the female, and are then expelled in a pouch, colloquially known as a mermaid's purse, made of collagen protein strands. Beachcombers can find the pouches, often with tendrils twirling from one end.

The waters where the eggs were found are part of the Fernando de Noronha Marine National Park, which is administered by the Chico Mendes Institute for Biodiversity Conservation, the administrative arm of the Brazilian Ministry of the Environment.

This story was provided to Newsweek by Zenger News.