Aquatic answers: Why do sharks bite more people in Hawaii?

Sharks and people are competing over vacation hot spots, scientists report in a new study of Hawaii's shark population. 

Caleb Jones/AP
Sand and hammerhead sharks swim in a holding tank at the University of Hawaii’s Institute of Marine Biology on Oahu’s Coconut Island.

Sharks prefer the waters near some of Maui's most popular beaches, where many shark attacks also occur each year, according to a study released Thursday by scientists studying Hawaiian shark populations. 

Yet scientists at the Hawaii Institute of Marine Biology say that one of the most important lessons the study can teach swimmers is not one of fear. Instead, they point to the role the study can play in teaching people how to coexist with their aquatic neighbors.

"Swimming in the ocean is swimming in what amounts to a wilderness environment. Sharks are part of this environment," Bruce Anderson of Hawaii's Division of Aquatic Resources told the Associated Press. "We have to accept that they're there and take precautions to avoid encounters, which are going to occur from time to time."

Warming ocean temperatures mean that typical shark habitats have expanded. And as shark territories expand, so do the numbers of encounters between human and sharks, some of which have resulted in injury.

Yet scientists say that humans share some of the blame for attacks. More humans partake in ocean recreation each year, expanding activities such as surfing or paddleboarding right into the environment where sharks eat, live, and socialize.

Although shark attacks are on the rise, the trend "most likely reflects the ever-increasing amount of time spent in the sea by humans," increasing opportunities to bump into each other, according to a yearly report summary by the 2015 International Shark Attack File. 

The study released on Thursday was conducted over two years, and specifically studied sharks in Hawaii. Researchers determined that sharks in Hawaiian waters are not only naturally attracted to the area near Maui due to its coral reefs and food supply, but that the area is also a popular mating season hangout for sharks from Oahu's waters.

As for increasing shark bites in the waters near Maui, well-populated by both sharks and humans, researchers came to the same conclusion as those who conducted the 2015 International Shark Attack File report.

"The ingredients that have gone into a general upward trend in the number of shark bites in Hawaii, and other places around the world," study author Charles Meyer told the Associated Press, "are mainly more people in coastal areas going into the ocean and doing a wider array of ocean recreational activities."

The key to coexistence, according to shark experts, is knowledge. Humans should avoid murky water or swimming near dead animals and other known shark prey, such as seals. When it comes to shark interactions, an ounce of prevention is worth a pound of cure.

It's also worth remembering that sharks are a key part of ocean ecosystems, Francisco Ferretti, of Hopkins Marine Station at Stanford University, tells The Christian Science Monitor. 

Without large sharks, smaller shark and ray populations increase, negatively impacting fisheries. One study of northeast shark populations found that when shark populations decreased, scallop fisheries suffered from the proliferation of other predator fish.

Dr. Ferretti says that when humans understand sharks' seasonal movement, behavior, and population structure, they can both better avoid attacks and make smart choices that allow them to participate in recreational activities.

"Shark attacks are still very rare," says Ferretti. "You have a higher chance of winning the lottery than being attacked by a shark."

Although odds vary by activity, humans have about a 1 in 738,000,000 chance of being attacked by a shark while participating in ocean activities.

"If we know them, and we know their ecology, then we can take precautions and use the ocean and engage in recreational opportunities," says Ferretti. "These predators are a fundamental part of the ocean function."

As researchers and public officials alike come to this conclusion, organizations and shark advocates have stepped forward to try to help humans and sharks coexist in harmony.

One Cape Cod, Mass., town has embraced its seasonal neighbors. Home to some of the state's most popular beaches, the town of Chatham hosts summer parades, art festivals, and movie showings celebrating the great white sharks that hang out each summer offshore.

Change is occurring at the national level as well. Late last summer, the Monitor reported on a group of shark attack survivors who have become advocates for the animal, urging Congress and beachgoers not to demonize sharks, but to try to better understand them.

In response to the latest Hawaiian study, the state plans to increase its educational outreach.

of 5 stories this month > Get unlimited stories
You've read 5 of 5 free stories

Only $1 for your first month.

Get unlimited Monitor journalism.