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10/3/05 - Cutthroat Ecosystem
by David Nichols, State of Hawaii, DLNR, HIHWNMS

A curious monk seal approaches as the REA divers exit the water at Kure Atoll. Photo by Darla White

At Pearl and Hermes Atoll, as we retrieved our bottom longline that had been baited with chunks of various fish, we began pulling up half-eaten 8-foot Galapagos sharks. Later, I watched as a group of wrasses swam together. They were similar in size and had probably grown up together on the reef - life-long buddies. However, as soon as a collection tool injured one, the others would immediately begin devouring any exposed pieces of its flesh. While collecting reef fish specimens for DNA studies, Carl Meyer was removing a specimen from the collection device. A large ulua watching the action attempted to swallow the fish (along with Carl’s hand) before he could get the fish into the collection bag. Carl, choosing to keep his fingers, yielded to the ulua.

There are the mantis shrimps here with an ability to think and learn that puts them way ahead of their arthropod kin. These guys are voracious predators that spear, slash or smash their prey (i.e. fish) with their greatly enlarged second pair of legs. This action can take less than 5 milliseconds and the victim is then ripped up and devoured. There are even single-celled, ciguatoxin-producing dinoflagellates that reside upon other algae in the reef ecosystem. If an organism devours enough of this toxin (either directly or by ingesting an organism that has accumulated the toxin) it can become sick and/or die.

The peaceful, serene image of the Northwestern Hawaiian Islands coral reef ecosystem that I had previously developed has been shattered. The brutal and savage nature of this reef ecosystem puts it right up there with the Serengeti plains and the Amazon basin. As with most places on this planet -- this is no place for the weak.

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It has been suggested that we nominate the Hawaiian monk seal for possible inclusion in our “unofficial poster critter” competition. Sure, monk seals have been around for umpteen years, they are endemic to the Hawaiian Archipelago and the young pups are pretty darn cute. Nearly the entire population is found in the NWHI but declines make the monk seal one of the most endangered marine mammals in the United States. I am not convinced they have what it takes to make it on our NWHI Poster. They just might be a little to “sensitive” for our brutal, cutthroat ecosystem poster.

The nominee for today comes from the fish team - the crosshatch triggerfish. These fish are rarely seen in the MHI (too deep) but here in the NWHI they are quite common. The ‘trigger’ alone makes them tough enough to be on the list of nominations. Triggerfish have a thick first dorsal spine that can be erected and locked into place by the second. This is to lock themselves into crevices when frightened or sleeping making them almost impossible to remove. They have tough hides and strong jaws that enable them to eat almost anything from crustaceans to coral. They are definitely tough enough to make our list.

A pair of crosshatched triggerfish hang out near the reef at Midway Atoll. Photo by Darla White

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