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Cookiecutter Shark Research

HCSA- Supporting the Legacy of Hawaiian Channel Swimming with Worldclass Standards

HCSA IS THE FIRST AND ONLY OCEANS 7 GOVERNING BODY TO IMPROVE SWIMMER SAFETY THROUGH MARINE ANIMAL RESEARCH. THIS RESEARCH, COMPLETED LATE 2023, LED TO ACTIONABLE DATA AND IS NOW THE MODERN SAFETY STANDARD FOR CROSSING DEEP HAWAIIAN CHANNELS LIKE KAIWI AND ʻALENUIHĀHĀ.

HCSA's official position statement regarding the Molokaʻi (Kaiwi), ʻAlenuihāhā, Kaulakahi, and Kaʻieʻiewaho Channels:

In addition to considering sea and weather conditions and sun exposure duration, a strong recommendation supporting human safety can be made to structure channel swimming so that a swimmer transits through the zoogeographical habitat (the deepest portions of the channel) of Isistius spp. (cookiecutter sharks) during moonlit nights or daytime.

Read the 2023 publicly available research about shark attacks in Hawaiian waters made possible by data collected by HCSA and analyzed by Maui Nui Swim here.

HCSA recognizes the best practices developed by Steven Minaglia for crossing the Molokaʻi Channel.

Check out his strategy to reduce cookiecutter shark bites implemented early 2024 and this Instagram video.

December 11, 2025 University of Hawaiʻi researchers Suca, et al. further establish the connection between moonless nights and cookiecutter shark attacks on channel swimmers.

"Muku ka malama, nanahu ka nahunaiki o ka pō. When the new moon arises, the cookiecutter shark bites.

Click the links below to learn more:

Researchers find link between shark bites and moonResearchers say there is a link between shark bites and the presence of the moon.

Researcher analyzes cookiecutter shark bites among channel swimmersA recent study from University of Hawaiʻi researcher Steven Minaglia, a channel swimmer himself, found a striking association between cookiecutter shark bites and moonless nights. Speaking to The Conversation's Maddie Bender, Minaglia said he's going to keep a close eye on swimmers for recurring patterns.

Check out this Animalogic video if you are interested in the cookiecutter shark.

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