When an open water swimmer or their crew is approached by or approaches a shark or group of sharks within their visual range, we refer to this as a shark encounter.
There have been – and will continue to be – innumerable shark encounters during training sessions, open water swims, and channel crossings around the world. It is most certainly a scary situation, but there is no physical contact between the swimmers and the sharks in these situations.
In contrast, a shark attack is when the shark physically touches or bites a human, whether out of curiosity, fear, hunger, or mistaken identity. The International Shark Attack File, under the direction of members of the American Elasmobranch Society, tracks the number, location, autopsy reports, background information, and graphic photos in a global database.
An example of the reports include that of the tragic passing of 74-year-old veteran open water swimmer Burgert van der Westhuizen who died while swimming along his normal coastline course in Jeffreys Bay in South Africa. Read the International Shark Attack File report here, another report here, and listen to first-hand report by Terry Olivier below.
There are 6,901 shark attacks documented in this file that can be downloadable here.
Out of curiosity, we attempted to research what shark attacks have occurred during a channel crossing or an official ocean swimming competition. These are our preliminary findings, but we believe there are many others.
Shark Attacks on Channel Swimmers or Competitive Ocean Swimmers
- Michael Spalding (61) in the Alenuihaha Channel in Hawaii on 16 March 2009 (cookiecutter)
- Charlotte Brynn in the Catalina Channel in Southern California on 29 August 2013 (leopard)
- Eric Schall (58) in the Molokai Channel in Hawaii on 18 March 2019 (cookiecutter)
- Isaiah Mojica (23) in the Molokai Channel in Hawaii on 5 April 2019 (cookiecutter)
- Adherbal Treidler de Oliveira (49) in the Molokai Channel in Hawaii on 29 July 2019 (cookiecutter)
- J. Andrew Walberer, PhD (50) in the Molokai Channel in Hawaii on 19 March 2023 (cookiecutter)
To compile a more comprehensive historical global list, please send information on confirmed attacks to headcoach@openwatersource.com.
Shark Attacks During Hawaiian Channel Swims
For more information about shark attacks in Hawaii, channel swimmer Dr. Steven Minaglia and open water swimming biostatician Melodee Liegl wrote a scientific paper Moonless night sky increases Isistius species and live human contact for bioRxiv, an open access preprint repository for the biological sciences co-founded by John Inglis and Richard Sever.
The abstract reads, “The nocturnal feeding behavior and zoogeographical habitat of cookiecutter sharks Isistius brasiliensis and Isistius plutodus (Isistius spp.) greatly reduces interaction of this species with live humans. Attacks on live humans are exceedingly rare with 7 cases reported worldwide, 6 of them in Hawai‘i, and 5 of these occurring among channel swimmers.
Published research suggests that periods of bright moonlight may increase Isistius spp. contact with live humans and does not otherwise identify significant trends or risk factors.
Yet 5 of the 6 Isistius spp. bites on live humans in Hawai‘ian waters occurred with the moon set and after nautical twilight end and before nautical twilight start.
From 1961-2023 in Hawai‘i, 129 successful solo channel crosses and 5 Isistius spp. related injuries in the habitat of cookiecutter sharks were analyzed across two groups:
- one where both the moon and sun were set (dark group) and,
- one where the moon and/or sun was in the sky (light group)
There was a significant difference for swimmers bitten by Isistius spp. in the dark 4 (12%) versus light groups 1 (1%), p=0.012, RR 12.6 (95% confidence interval: 1.5-108.9). Swim start time and year was also significant (Pearson correlation 0.566, p <0.001).
Swimmer gender and use of shark deterrent devices and artificial illumination were not significant.
The growing popularity of channel swimming in Hawai‘i and swim start times have contributed to an increasing likelihood of live human and Isistius spp. contact and a moonless night sky is a significant risk factor for this interaction.
A PDF of the paper can be downloaded here and read in its entirety.
Dr. Minaglia writes, “The data is small and the paper in review, but I think it is timely and will influence behavior in a positive way. It shows a striking risk profile (1-in-8 chance of cookiecutter shark bite with moon and sun set with no light in the sky versus a 1-in-101 chance with moon and/or sun in the sky) when crossing the deepest part of the deep channels in Hawaii. The paper is worth disseminating at this time because of its commentary on human safety.”
Download here – it is a fascinating read.
Photo above courtesy of Charlotte Brynn at BrynnSwim.
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