November 22, 2024

Filmmakers document potential great white shark birthing site

Wildlife filmmaker Carlos Gauna and University of California-Riverside biology doctoral student Phillip Sternes might have witnessed one of the marine world’s most elusive occurrences — the birth of a great white shark in the wild. Documented in the journal Environmental Biology of Fishes, this sighting off California’s central coast could revolutionize understanding the sharks’ reproductive habits.

White Sharks in the Wild

On July 9, 2023, while scanning the waters near Santa Barbara, the duo observed a phenomenon never before recorded in the wild — a live newborn great white shark. Newborn great whites are distinguished by a unique white layer covering their entire body. Gauna, who has spent thousands of hours filming sharks, captured this event with his drone camera.

“Where white sharks give birth is one of the holy grails of shark science,” Gauna said. “No one has ever been able to pinpoint where they are born, nor has anyone seen a newborn baby shark alive.”

This roughly five-foot-long shark displayed an unusual pure white coloration, contrasting the typical gray and white body of adults. Upon closer examination, Sternes noticed that the white layer was shedding from the shark’s body as it swam.

Video captured by Carlos Gauna, also known as TheMalibuArtist.

“We enlarged the images, put them in slow motion, and realized the white layer was being shed from the body as it was swimming,” Sternes said. “I believe it was a newborn white shark shedding its embryonic layer.”

This observation could provide unprecedented insights into the great white’s birthing practices, a topic that has long perplexed scientists. While acknowledging the possibility of a unique skin condition, the paper’s authors lean towards the newborn theory for several reasons.

Firstly, while in utero, the embryonic sharks might feed on unfertilized eggs for protein. The mothers offer additional nourishment to the growing shark pups with a ‘milk’ secreted in the uterus. 

“I believe what we saw was the baby shedding the intrauterine milk,” Sternes said. 

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Secondly, there was the presence of large, likely pregnant great whites in this location. Gauna had observed them here in previous years, as well as in the weeks leading up to the observation.

An Exciting Find for Conservation

“I filmed three very large sharks that appeared pregnant at this specific location in the days prior. On this day, one of them dove down, and not long afterwards, this fully white shark appears,” Gauna said. “It’s not a stretch to deduce where the baby came from.”

The size and morphology of the observed shark are consistent with those of a newborn. Its thin, short, and rounded appearance made Sternes believe it could only be hours or a day old.

Finally, the central California coast has long been hypothesized as a birthing location for great whites, but until now, there has been no definitive evidence. The proximity of the sighting to the shore — about 1,000 feet from the beach — suggests the shark was likely born in shallow waters, contrary to the belief that great whites are born farther out at sea.

This discovery holds critical implications for great white shark conservation. With white sharks listed as endangered, confirming these waters as a breeding ground could lead to enhanced protective measures.

“Further research is needed to confirm these waters are indeed a great white breeding ground,” Sternes said. “But if it does, we would want lawmakers to step in and protect these waters to help white sharks keep thriving.”