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What is believed to be the first genomic study of white sharks in the Western North Atlantic has yielded fascinating results that are helping scientists further understand these apex predators and their patterns.
A recent DNA study conducted by OCEARCH revealed that two of the white sharks tagged by OCEARCH in 2021 and 2022 are actually brother and sister.
According to OCEARCH, the study revealed three pairs of full siblings and seven likely half-sibling pairs of great white sharks.
The study found that one full sibling pair is believed to have come from the same litter, while the two other sibling pairs are believed to be five and 19 years apart.
“The collaborative research, conducted using genetic samples collected by OCEARCH and collaborating scientists, marks the beginning of an entirely new chapter in understanding white shark biology and ecology,” OCEARCH said.
The goal is to help better understand why white sharks return to the same habitats year after year, by investigating whether family relationships help explain the patterns.
“This research changes the questions we can ask,” said Chris Fischer, founder and expedition leader of OCEARCH. “For most people, white sharks are the ultimate lone predator. But every expedition reminds us the ocean is more complex than we imagine. For years, OCEARCH has helped reveal where white sharks travel across the Atlantic. Now we’re beginning to understand the families behind those journeys. Every new discovery brings us closer to understanding how these remarkable animals live, reproduce, and survive—and that knowledge is essential to returning our world’s oceans to balance and abundance.”
Scientists originally noticed in 2025 that Jekyll’s migration patterns were nearly identical to another tagged white shark named Simon, leading them to wonder if the two sharks were related.
While the analysis revealed Simon and Jekyll weren’t related, they did find that Jekyll and another white shark, Olympia, were siblings with the same parents, born five years apart.
Olympia was tagged in 2021 as a juvenile white shark off the coast of Cape Cod. Her OCEARCH tracker stopped publicly releasing data in 2022.
Jekyll, also a juvenile at the time of tagging in 2022, was tagged off the coast of Jekyll Island, Georgia, hence his name. His tracker stopped publicly releasing data in 2024.
OCEARCH said researchers also found that each of the full sibling pairs had been sampled in similar seasonal habitats—one sibling in the southeastern United States during winter or spring and the other in New England or New York during summer or fall.
And while this information is important, researchers stressed it does not mean that white sharks recognize one another, intentionally travel together or inherit their migration routes.
“This study is really the beginning, not the end,” said Dr. David Portnoy, an OCEARCH collaborating scientist and principal investigator of the study conducted at Texas A&M University-Corpus Christi.
“We’ve identified close family relationships among Western North Atlantic white sharks, but we’ve only scratched the surface of what those relationships may tell us. By integrating genomics with years of satellite tracking data, we can now begin exploring whether related sharks share similar patterns of habitat use or migration. Those are exciting scientific questions, but they’ll require additional research before we understand exactly what patterns exist and why.”
The findings also raise the question of population size in the Western North Atlantic. With multiple sibling pairs identified from a small sample collection, it could suggest a small population of white sharks.
OCEARCH said if supported by further analysis, this finding could have significant implications for conservation policies aimed at rebuilding the Western North Atlantic white shark population.
“For OCEARCH, the findings represent another milestone in its mission to transform our understanding of white sharks and the oceans they help sustain. The organization has spent nearly two decades building the world’s largest open-access database of white shark movement and biological information,” OCEARCH said.
“This latest research expands that mission from documenting where sharks travel to exploring how family relationships may shape their lives across generations.”
Track great white sharks like Olympia and Jekyll with OCEARCH’s free global shark tracker app.
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