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9/24/05 - Predators everywhere
by David Nichols, State of Hawaii, DLNR, HIHWNMS

Yannis Papastamatiou, Carl Meyer, Randy Kosaki and Matt Craig prepare to implant an acoustic transmitter into the abdomen of a 12-foot tiger shark. HI-2 vessel operator, HI'IALAKAI Crewmember Merlyn Gordon keeps a watchful eye on the team.

Today was jam-packed with excitement from start to finish. We finally made it to Pearl and Hermes Atoll after a sleepless evening of rocking and rolling (the vessel not the night-life). The apex predator team started the morning setting some bottom longlines (baited with large chunks of shark meat) in hopes of catching some large sharks (i.e. tiger sharks). Next we spent a little time trolling for suitable uku in which to place a few transmitters. They managed to catch at least four of the largest uku I have ever seen. Receivers were implanted successfully and we were barely an hour into our day.

Next, we needed to retrieve the three receivers that were strategically placed around the atoll. At the site of the last receiver pick-up the team chose to scuba dive to also collect the required reef fish specimens for the various research projects. As I descended with the team my initial impression of the reef below was calm and peaceful. There were a few ledges but for the most part the area was flat with little structure. As I got closer to the bottom the reef life came into view and my impression started to change. I saw fish that I have never seen elsewhere in Hawaii. Fish that I had no idea even existed - I took photographs of those I could get close to so I could later identify in the lab back on the Hi`ialakai.

The collecting method used by the team for reef fish occasionally leaves a little blood in the water. I don’t know if there is a correlation, but as the dive progresses more and more Galapagos sharks show up to do their own little surveying. At one point during the dive I counted eight sharks all about eight feet in length including a couple that were lazily swimming among us. There were numerous large, very aggressive jacks (ulua) in the area that would also that would attempt to steal the reef fish specimens as they were collected. Toward the end of the dive, in an attempt to discourage an attcking school of ulua from stealing specimens, lead scientist Randy Kosaki began pushing them away from his bag with his three-prong spear. One of the ulua began to swim erratically. That was all it took for the sharks to begin to devour the animal. In just a few moments a writhing mass of gray bodies descended on the ulua. In seconds, there was nothing left of it, and the sharks were still agitated and now looking for some new “action”. When I looked around this time there were more sharks in the area than I could count. This calm and peaceful reef was anything but. It was time to ascend!

Carl Meyer of HIMB releases an uku after implanting an acoustic transmitter into its abdomen.

After another brief period of collecting - in a completely different location - it was time to retrieve the longlines. The lines began coming in a little tangled which would indicate something large and active was on the line. Then some smaller six-foot sharks began coming up on the hooks. I am just guessing at the total length here because these sharks were coming up with the back half of their body completely bitten off - cleanly - in a single bite. Next to come up on the line (or at least start to come up) was a large tiger shark around 12 feet in length. As this shark was being pulled near the boat the shark was able to spit/regurgitate the hook and bait. As we continued to pull in the line we realized that it had spit out a half-eaten Galapagos shark that had been caught on our hook.

Next on the line was another large (12 foot) tiger shark. This one was actually hooked in the jaw and we were able to bring it alongside the small boat for measurements and to implant a transmitter into the abdomen. This wasn’t the last large tiger shark - there were two or three more that came up on the line in which we managed to implant transmitters.

Today was all about sharks. There seems to be plenty of them. The research being done today will help us understand just how far these sharks are traveling. I don’t wish to perpetuate that myth that sharks are brutal creatures that should be feared but, after what I witnessed today, they definitely deserve our respect.

Yannis Papastamatiou, shark biologist from HIMB, retrieves an acoustic tag receiver at Pearl and Hermes Atoll.

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