Wednesday, October 14, 2009

Swimming with the sharks for science

These are the kind of stories shark diving folks like to read. Found on the Big Island Weekly Blog this week - kudos to Nick Whitney and team:

A whitetip reef shark research project has some Big Island photographers literally swimming with sharks in the name of science.

Nick Whitney, a postdoctoral scientist now with the Center for Shark Research Mote Marine Laboratory in Sarasota, Fla., started a Hawaii whitetip photo identification project in 2002 as part of his Ph.D. research at University of Hawaii at Manoa. The findings of the project, which required the help of several underwater photographers around the state, will be published in a scientific journal within a year and will be available on the Web site, http://www.whitetip.org.


"I was planning to do a telemetry (tracking) project on whitetip reef sharks to study their movements, but found that while it was easy to dive with them and take pictures of them, it was very difficult to catch them in places that were good areas for tracking," Whitney said. "I was also looking for a way to involve the community in my research, and since these animals are easy to photograph and have unique markings on their sides, photo-identification seemed like a great way to do that."

Whitney been involved with studies on tiger sharks, sandbar and Galapagos sharks in Hawaii. He said that while he's interested in all these species, whitetips are the most intriguing because there has been little research done on them. As an added bonus, they can frequently be seen while diving in shallow water and don't immediately swim away like other species.

Whitney was able to identify at least 178 individual white tips throughout the state. Most were only sighted once, but over 50 were sighted multiple times.

"A few individuals, usually adult females, have been seen repeatedly -- seven to 10, up to 13 times for one individual from 2001 to 2008. That was an adult female at the dive site called "Suckemup" near the Honokohau/ Pine Trees area on the Big Island," Whitney said.

The project revealed that whitetip reef sharks move around more than anyone expected.

"We found movements of as much as five to six miles to be more common than we expected, and one animal moved over 16 miles along the coast," Whitney said. "We also had two animals cross a relatively deep, 450-foot, channel between Molokini crater and Maui, which certainly isn't the same as an inter-island crossing, but our genetics study indicates that the inter-island channels are not significant barriers to gene flow. It turns out to be true that some sharks will return to the same area for years, but they're not always there and will often be absent for months at a time before returning."

On the Big Island, Cynthia Hankins, Dee Wescott, Vicky Newman, Bryce Groark and Porter Watson contributed photos for Whitney's project. Divers on other islands also contributed significantly. The Honokohau area was one of the spots where many of the Big Island images came from, Whitney said.

"We only got a few photos from other sites which were often a long way from Honokohau, which meant we had a very low probability of detecting any movements," Whitney said. "Fortunately we had a few very dedicated photographers working the Honokohau area and were able to find out that at least two females seem to repeatedly use this area as a place to gestate, and possibly give birth. Also most sharks give birth every other year, and that seems to be the case for whitetips as well, but our photos from Honokohau show that at least one female was able to get pregnant two years in a row. She was photographed very late-term in both years."

Hankins, a Kona resident, has photographed the Kona Coast from as far south as Paradise Pinnacle (Near Paradise Park) and as far North as Malae Point in North Kohala.

While Hankins says she can recognize some of the whitetips she photographs, the tracking and information gathering is best left to Whitney. She first learned of Whitney's research when a friend who knew of her shark fascination introduced her to the project. Whitney taught her about reef sharks and she provided him with sighting data and images to aid in his research, she said. Hankins has been forwarding him photos for the past four years, and encouraging other Big Island divers to do so as well.

Hankins said when she's taking photos for the project, it's important to get certain angles, so that Whitney can identify the different whitetips. Taking photos for scientific purposes requires a different approach than normal underwater photography.

"I recognize a few individuals by sight and have seen them repeatedly, frequently at the same couple of sites," she said. "I've also been adding tiger shark photos to a new page on Nick's sighting Web site. The tigers aren't seen as frequently as the whitetips, but I have seen the same animals on several occasions."

Hankins said she's seen and photographed pretty much everything one would expect to find in Hawaii waters -- and then some.

"I've seen most everything in the fish and creatures ID books for the Hawaiian waters. One day I found a new species of nudibranch (sea slug) which is sitting in a lab in California waiting to be described," Hankins said. "I've seen a juvenile humpback whale being attacked by 25 tiger sharks. I've watched octopus mating; Manta rays breaching; turtle trying to mate; eels attacking each other; and so many more amazing things."

When it comes to swimming with sharks, Hankins has her own rules of engagement.

"The whitetip reef sharks are pretty harmless if you don't provoke or disturb them. They are usually resting in the mornings, which is when I dive most often and we find them sleeping in the shadowy areas under arches, ledges or in lava tubes," Hankins said. "If you approach slowly you can get quite close. It's always exciting to see an animal as big as yourself with the ability to inflict damage. You always want to approach with a respect for their space and try not to disturb them or corner them."

Some of her other subjects, however, are not as friendly.

"The tiger sharks on the other hand are very scary. They are twice to three times the size of the whitetips and have a stealthy and menacing look," Hankins said. "I try to remind myself that they are not interested in eating me, they are just curious. None the less, the adrenaline always rushes and my heart pounds. Rarely will they linger for very long so the shots need to be quick."

To view and purchase underwater images from Hankins, visit http://www.cynthiahankins.com.

Whitney cautioned that taking photos of sharks can be dangerous, if not done correctly.

"Any large, wild animal -- and many small ones -- has the potential to be dangerous in one way or another, but whitetips are very docile and I would even say 'tolerant' of human activity to a large extent. Over the course of trying to tag them and collect tissue samples for our genetics study I've done many things that should've gotten me bitten and didn't," Whitney said. "They're not teddy bears though. Grab one and hold on long enough and it will grab you back."

Although Whitney's completed his studies at UH-Manoa and now works in Florida, he wants to keep the whitetip reef shark project going. The long-term data complied is very valuable, he said.

"I hope to keep collecting photos and information and publish additional studies on whitetip reef sharks of Hawaii in the future," Whitney said.

People can submit photos at http://www.whitetip.org or can e-mail them to whitetip@hawaii.edu.

2 comments:

DaShark said...

Great initiative!

Which of course begs the question: may this be disrespectful of the 'aumākua? (:

Horizon Charters Guadalupe Cage Diving said...

Absolute disrespect. Unless you happen to be not of the anti-shark diving political class then it's A-O.K!