KAHULUI - Sticking your hand inches away from the jaws of a 14-foot-long tiger shark certainly isn't your average day at the office, but for University of Hawaii professor Carl Meyer and his crew it's just part of the job.
Meyer and three graduate students returned to Maui last week to tag tiger sharks around the Valley Isle as part of the two-year, $186,000 study commissioned by the state Department of Land and Natural Resources last year. Over the course of four days, the team tagged a total of nine tiger sharks along the island's north shore and fitted six of those animals with satellite transmitters that allow the public to track the sharks' movements online.
So far, the research team has tagged a total of 20 tiger sharks around Maui, and 13 of those have been fitted with a satellite tracker, which each cost $1,700, Meyer said.
"I think you can see we've already made some pretty big inroads into pulling back the veil on behaviors of tiger sharks around Maui," Meyer said. "You can now go online and see our satellite tracks. Before, people speculated what tiger sharks did around Maui, whereas now you can actually see what they're doing."
The Maui News was able to observe one of Meyer's shark-tagging excursions off Kahului Harbor on Tuesday morning.
Around 6 a.m., the team launched into the harbor in a 17-foot Boston Whaler to "set the lines." Each line is more than 1,600 feet long and has 10 hooks baited with fish heads and other scraps that the researchers have collected from local fish markets. The crew put out a total of three lines Tuesday morning in waters up to 240 feet deep and three miles offshore before returning to Kahului Harbor.
UH grad students Melanie Hutchinson and Mark Royer wrestle with a 12-foot tiger shark Tuesday afternoon about three miles off from Kahului Harbor. The creature was tagged as part of a two-year study commissioned by the state Department of Land and Natural Resources.
The Maui News / CHRIS SUGIDONO photo
University of Hawaii grad students Melanie Hutchinson and Danny Coffey tag a tiger shark with a satellite transmitter Tuesday afternoon.
The Maui News / CHRIS SUGIDONO photo
UH professor Carl Meyer (from left) and his team of graduate students — Melanie Hutchinson, Danny Coffey and Mark Royer (not pictured) — tagged a total of nine tiger sharks, including this 12-foot female, on Tuesday.
The Maui News / CHRIS SUGIDONO photo
The team usually leaves the lines out no more than three hours because, if the lines are left out for too long, the sharks caught will get weak and start to die, Meyer said.
Around 10 a.m, the team set back out to retrieve the lines.
It's a grueling process and one that can take all day, depending on how many sharks have been hooked. The four-member crew takes turns standing at the helm of the boat, pulling in the line by hand. They know there's a shark on the line when they feel the line tug in different directions, Meyer said.
The team caught three tiger sharks Tuesday - two small ones followed by a 12-foot-long female. Watching a shark thrash fiercely against a boat that seems to be tilting dangerously close toward the water is enough to put most people on edge, but the researchers get right to work. Pulling the line to bring the shark next to the port side of the boat, they quickly hook a rope around the tail and then flip it upside-down as fast as possible.
"It's a bit of a fight to get them upside-down, but once they're there they're very calm and docile," Meyer said. "It's referred to as tonic immobility, or catalepsy, and that calmness can persist for a while even after you flip them to the side."
The team implants an acoustic tag - about the size of a pinky finger - into the belly of the shark, and then, if it is a large shark like the one caught Tuesday, flip the animal to the side so they can implant a satellite tracker on the dorsal fin. A researcher quickly drills a hole in the cartilaginous fin and bolts the tracker on. To the shark, it feels "like getting your ear pierced," Meyer said.
"If the shark stays calm, we get it down in one go, but if it wakes up and gets lively, we'll roll it back upside-down," Meyer said.
The large female tiger shark tagged Tuesday stayed calm the entire 20 minutes it took to remove a broken satellite device and put in a new one. The shark had already been caught, tagged and fitted with a satellite device the day before, but had broken it while thrashing against the boat Tuesday.
This was the research team's second shark-tagging trip to Maui. The first trip was in October, when members tagged 15 sharks in South Maui waters around Makena and Kihei. During this month's trip, the researchers focused on areas from Waiehu to Paia, and they plan to return in a few months to tag sharks from Olowalu to Kaanapali.
So far, tiger sharks tagged for the Maui study range from 8 to 14 feet long, and Meyers said that it is important to track both males and females.
"We want both mature female and male sharks in our sample to avoid sex bias in the data, and thereby gain a better overall understanding of the spatial dynamics of large tiger sharks," Meyer said.
He added that all of the sharks they caught this month had mating scars.
"Getting up close and personal with the sharks, that's a huge privilege because they're incredible animals," said Mark Royer, a UH graduate student who has been tagging sharks with Meyer for the past two years. "For a normal person, seeing a 13-foot tiger shark would be a highlight for years to come, whereas we see five in one day."
Researchers are searching for answers to questions that have surfaced in light of the unprecedented spike in shark attacks around Maui last year, including two fatal attacks. Of the 14 shark bite incidents statewide in 2013, eight happened in waters off Maui.
Why have there been so many shark attacks around Maui in recent months?
"If you really boil it down, there's two components to a shark bite incident - what the shark is doing and what the people are doing," Meyer said. "So if we look at what sharks are doing and rigorously compare their behavior in Maui and other places and don't find any real differences, then it suggests that the uptick is somehow driven by what people are doing."
Tourism numbers have been consistently on the rise, and activities like kitesurfing, standup paddling and kayak fishing, which take people farther off shore and into areas where sharks are more prevalent, have gained popularity in recent years.
In response to rumors that the uptick may be caused by an increased prevalence of green sea turtles, which have been federally protected since 1982, Meyer said that there is no evidence to support that theory.
"Just because the number of turtles have increased does not mean the number of tiger sharks have increased," Meyer said. "Tiger sharks have an extremely broad diet, so if one prey species becomes scarce, you can just go off and eat something else."
Tiger sharks have been known to eat porcupine and stick fishes, other sharks and rays. Meyer noted that in the last tiger shark diet study done, which was more than 40 years ago, turtles were found in only 15 percent of large tiger sharks, which meant that 85 percent of the sharks had not eaten turtles at all.
The fact that tiger sharks do eat a wide range of species may be the biggest reason against culling, one researcher said.
"Large sharks exert the most population regulation on smaller sharks, sharks make up the greatest component of the diet of larger sharks, so you want to keep those around to maintain ecosystem integrity," said UH grad student Melanie Hutchinson, who has been tagging sharks around Hawaii for the last seven years.
What we do know about tiger sharks so far is that behaviors vary greatly from individual to individual, and even within the same individual over time, Meyer said. They rarely hang out in the same spot. In fact, one of the sharks tagged in October traveled 630 miles southwest toward Johnston Atoll, stopped suddenly, turned around and came back and is now residing in the waters off of Kona.
"We know they like that very shallow area between Maui, Kahoolawe, Lanai, but those same animals are visiting Neighbor Islands. Some of them have actually gone and never come back, so far," Meyer said.
Less than five months into the study, it is too soon for any definitive conclusions, though the number of incidents is, statistically, still pretty low, Meyer said.
"Even though it may seem dramatic, when you look at it from a strictly mathematical perspective, it could just be elements of chance, combined with increased numbers of people in the water. We don't know for sure, which is why we're doing this study," Meyer said.
The public is able to track the movement of tiger sharks tagged around Maui at pacioos.org/projects/sharks.
* Eileen Chao can be reached at echao@mauinews.