Shark Biologist Kim Holland Discusses Hawaii’s Shark Population

Holland tagging a tiger shark.

Kim Holland has dedicated his career to learning about the ocean. After earning a bachelor’s and master’s degree from the University of Hawaii (UH) in biology and zoology and a PhD from the University of Pennsylvania in biology, Holland returned to Hawaii and began a career as a researcher professor at his alma mater. At UH, Holland heads up the Shark Lab, which specializes in organismic and superorganismic biology of marine organisms. As the name suggests, much of Holland’s research is focused on sharks and understanding their behavior and movements in Hawaiian waters. Here, the shark expert shares how he got into biology, why Maui sees the greatest number of shark attacks in the state, and common misconceptions about sharks.

I started in marine biology as a student mainly because I was only good at two things: surfing and biology. I’ve been involved with different aspects of marine biology for years, mostly looking at open water fishes like tuna and marlin. I was involved when the earliest electronic tags were being invented—we were using acoustic transmitters on tuna to see what their movement patterns were in Hawaiian waters. I was happily doing that back in the ’80s when there was a spate of fatal shark attacks. We realized the tracking methodology that we’d been using on tuna could very easily be used transferred to look at the movement patterns of sharks.

What is your research at the Shark Lab focused on?

At the moment, we’re really interested in understanding the movement of big sharks in Hawaiian waters. These increasingly sophisticated tags can tell us where the animal is and how deep it’s diving. It can also collect and store in its memory information about the water temperature. So, sharks are not just telling us what they’re doing, but they’re also telling us about the environment which they’re swimming in.

What are some of the most interesting things you’ve learned through your research?

Electronic tags allow us to see where sharks go and gives us indications of how deep the animals go. Before groups around the world started putting these more sophisticated devices on animals, we thought that sharks were close to the surface most of the time. But what we now know is that even species like tiger sharks, which we associate as being a shallow water species, frequently go down to 1,000 feet. The vertical dimension of shark behavior is something which is new to us and is surprising.

Why does Maui have the most shark attacks in the state?

What our research has shown is that the sort of sweet spot for tiger sharks and the habitat they prefer is between shoreline and out to about 600 feet of depth. There is much more of that preferred habitat around Maui than there is around any of the other islands. That same preferred habitat is also where a lot of the ocean recreation is sighted on Maui. So, you’ve got habitat that the sharks like and you’ve got habitat that humans like and they overlap more in Maui than they do in other parts of the islands.

Why do most shark attacks typically occur?

We actually have no idea. The majority of shark attacks are a one bite event, so it’s almost as if it’s an exploratory bite by the shark rather than a full-on attempt to devour the victim. We do know from other observations that tiger sharks are shy and are very cautious about what they eat. They take their time to decide whether to bite something or not—they’re not these crazed killers, they’re actually quite cautious.

When you figure that sharks are common in Hawaii and we know that tens of thousands of people go in the water every day of the year, the fact that we have just a handful of attacks is more surprising to me than the number that we do have . Most attacks are not fatal—that’s an important fact to remember.

What are some steps people can take to stay safe in the water?

Don’t go in the water by yourself. A lot of the fatalities come from people bleeding to death and going into shock. If you have somebody in the water with you that can help you get to shore, call for help, put a turnstile on you, or in other ways assist you, that makes a big difference to your chances of surviving an attack.

What are the most dangerous shark species?

In Hawaii, it’s almost always tiger sharks. Around the world, there are three basic species that cause problems to humans: white sharks, tiger sharks and bull sharks.

What are some common misconceptions about sharks?

One of them is that they are parked in front of certain beaches, lurking and waiting for somebody to put their toe in the water. There may be cases where a shark is more or less resident, but from a scientist’s perspective and for tiger sharks particularly, they’re always on the move and travel great distances. The other is that sharks are constantly hungry and anything that comes close will be attacked and that’s simply not the case. They’re really cautious most of the time and are quite selective in what they eat.

Anything else?

One of the things that we need to remember is that we’ve only scratched the surface in terms of understanding sharks in general. There’s still very much to learn about sharks and their biology.

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