In a move that has baffled scientists, one of the world's rarest marine mammals—the Hawaiian monk seal—is setting up shop on the populated islands of Hawaii.
With a population that hovers around 1,100, most of the world's silvery, seven-foot-long (two-meter-long) monk seals live on the uninhabited northwest Hawaiian Islands, in the Papahānaumokuākea Marine National Monument.
They've lived there for as long as Western history records, said Charles Littnan, lead scientist with the U.S. National Oceanic and Atmospheric Administration's Hawaiian monk seal research program in Honolulu.
But their population has been in decline for the past 30 to 40 years. Scientists are still trying to figure out why.
In the late 1990s, however, this endangered mammal saw a glimmer of hope, with a noticeable uptick in monk seal numbers on the main Hawaiian Islands like Kauai, Molokai, and Oahu. Together, the islands are home to over one million people.
Today, about 150 to 200 monk seals—roughly ten percent of the total monk seal population—call the main islands home.
"In the main Hawaiian Islands, totally counterintuitively, you have a population of seals—still relatively small—that is growing at about seven percent a year," Littnan said. "All the animals are fat, healthy, and happy."
A New Competitor?
But some of the human residents aren't so enthused.
Fishermen who grew up locally, in an environment without monk seals, now feel like they're competing with the animals for the same resources, like octopuses and a fish locals call aholehole.
"I fish all my life on the ocean and never saw any seals," said Ray Arezo, a Hawaii resident who fishes to help feed his family.
"They know how to pick the net with their flippers," he said. "They go over, they bite [the fish], and grab it and take it off the net."
Littnan says that he has heard the seals described as "a swarm of locusts moving across the bottom of the ocean" and that they eat 600 pounds (272 kilograms) of fish a day.
"The largest a monk seal gets is 600 pounds, and most are considerably smaller," Littnan said. "So that's obviously a physical impossibility."
Tensions between seals and humans have produced local headlines about seal deaths under "suspicious" circumstances, even though it's a state and federal crime to harm or kill the endangered seals. (Related: "Who Would Kill a Monk Seal?")
The headlines provoked Littnan to investigate what monk seals really do while underwater, with help from some Crittercams—small video cameras mounted on animals to study their behavior.
"We're not here to sell monk seals to anyone," Littnan said. "We want the truth."
The preliminary results show that some of the community's perceptions of the seals are off. But Littnan knew that getting fishermen and other locals to accept the results of a study from a government scientist would be tough sailing.
Rather than conducting a scientific study in the usual way—collecting data, analyzing the results, publishing findings—Littnan wanted to involve locals from the get-go.
He hoped that involving the public in the study's planning stages, and getting preliminary data out quickly, would keep frustrations with the seals from boiling over.
"It buys us time," he said. "It hopefully saves a seal or two while we work to [answer] these more difficult questions in terms of what role or what impacts do monk seals really have and what level of fisheries interactions are there?"
In early 2012, researchers held four public meetings on the islands of Molokai, Kauai, and Oahu (map) to get public input on how to design their monk seal study.
Then Littnan and his team worked with locals on ways to analyze the hundreds of hours of video the project would collect, so that residents would be more apt to accept the results.
"There's no way we're going to be able to get every person in the public to sit down and watch 180 hours of Crittercam footage," Littnan said.
But when a Molokai resident suggested that Littnan employ local middle and high school students to analyze the footage for him, he embraced the idea.
Now, researchers take all their footage from video camera deployments—they've made eight successful ones to date—make two copies and send one copy to classes on Molokai. "They get the data before we get to look at it," Littnan said.
The hope is that if someone at a public meeting challenges the team's findings, students from the community can vouch for the footage.
Some of the students get very passionate about the project, Littnan said, and are frustrated that some people don't believe the results they've been getting from the video.
Early analysis from the three- to four-day Crittercam deployments—done in partnership with National Geographic's Conservation Trust—show monk seals doing a variety of things underwater: eating, swimming, and sleeping.
But to consume 600 pounds (272 kilograms) of fish a day, as Littnan has heard some locals allege, a monk seal would have to eat a pound of fish every 45 seconds. The cameras showed seals would sometimes spend 15 minutes trying to get just one fish.
And footage shows the seals totally ignoring the aholehole fish, the one some locals believed the animals were eating up.
"There's a lot of sleeping," Littnan said. Monk seals will wedge themselves under ledges on the seafloor and doze for 10 to 15 minutes at a time.
One camera caught a monk seal fending off sharks intent on stealing its meal of an octopus.
"We're blowing a lot of these misconceptions out of the water already," Littnan said.
And Littnan's plan for getting people to sit down at the table to start talking appears to be working. A recent public meeting with 170 attendees, from tourists to fishermen, was very friendly.
"There was information exchange happening," he said. "People left knowing more."
Taylor Heckman, a recent high school graduate from Oahu, won an essay-writing contest about monk seals and got to accompany Littnan and a team of researchers while they attached Crittercams to the marine mammals on Molokai in February.
"They get to see the community of monk seals in a whole different way than they've ever experienced because [the seals aren't] just lying on a beach asleep or being problematic in fishing spots," said Heckman, describing her fellow students watching the Crittercam videos.
Terry Heckman, Taylor's mother, agrees. "The Crittercams are fun to watch," Terry said. "It's really interesting to see what they're doing, so sharing the video is a good way to get people excited about monk seals."
Littnan is about halfway through the three-year project and plans to deploy at least 15 more cameras on monk seals.
It's still too early to definitively say how the marine mammals spend all their time while they're out to sea, but we have more insights than ever before.
Before, researchers didn't pay much attention to monk seals on the main Hawaiian Islands because there were so few of them, Littnan said.
"And now, it's one of the greatest hopes for the future of the species' existence," he said. "It's absolutely essential that we find a way to balance the needs of the animals and the needs of the people in order to make sure that these animals persist." (Related: "Caribbean Monk Seal Extinct, U.S. Officials Declare.")
Kyler Abernathy contributed reporting to this article.
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