KC3 Rough Draft: Undersea Intruders

The Hawaiian Islands are basically several volcanic rocks, isolated in the middle of the Pacific Ocean. This fact may have people questioning why anyone want to visit, much less live there. With our humid, subtropical year-round weather, one of the first places locals and tourists alike head to are the many beaches. Unlike man-made pools, taking a dip in the ocean is swimming in Mother Nature's aquarium. For those lucky enough to snorkel in a Hawaiian beach, or at least watch a documentary on Hawaii's reefs, you've probably seen schools of bright, colorful fish. Many people, including residents here, assume that all the marine animals are native. As hard as it is to believe, Hawaii, as much as anywhere else, has invasive animals intruding and altering the underwater ecosystem.

Currently, a rising concern of invasive marine species have been the ta'ape (blue-lined snapper), the to'au (black-tailed snapper), and the roi (blue-spotted grouper/peacock grouper). All three fish were introduced to the islands in 1950. Ta'ape, to'au, and roi were caught around the reefs of Tahiti, and released in Hawaiian waters intentionally, as a game fish, in hopes of boosting the declining local fish stocks. In these fishes' native habitats, their population is lower in numbers, as they have natural predators. Yet, in Hawaii, they thrive.

Hawaii's sub-tropical waters is a great place to breed ta'ape, to'au, and roi, being that there are no natural predators to control these invasive species' population. To survive, they eat smaller fish, such as parrotfish and surgeonfish. The Honolulu Advertiser quoted, "A University of Hawaii (UH) study estimated that in a three-square-mile area off the Kona Coast, roi eat 99 tons of reef fish annually- the equivalent of 8.2 million fish." The same article also stated that roi consumes about 146 reef fish per year. In the beginning years of these three fish being introduced, scientists did not see these alien species as a problem. "Roi seems to be filling a [food chain] role opened up by humans," said scientist Jan Dierking, of UH. Now people are starting to agree that invasive fish, especially ta'ape, to'au, and roi, are populating too much. One reason why roi's population is continuing to grow is answered by marine biologist, Norton Chan, at the Waikiki Aquarium. He explained that invasive species introduced to a foreign habitat do not have immediate natural predators. One way to control the over population of these fish is for humans to catch them. However, we don't usually eat them. "It [roi] has a stigma for the likelihood of ciguatera toxins," comments Chan.

Communities in Hawaii actually have begun to realize that invasive species, like ta'ape, to'au, and roi are depleting the reef of native and local fish. Darrel Tanaka, an avid diver from Maui, is one of them. "We wanted to make a tournament [for divers], but we didn't want to deplete the reefs, so we made it for invasive species," he stated. "Maui doesn't have the fish it used to have 10 to 20 years ago. This is a way to give back to the reefs." Maui's idea of 'Roi-Round-Ups' have recently spread to other islands, including Oahu.

Bibliography

"CDNN :: Mutant Aliens Attack Hawaii." Scuba Diving News :: CDNN - Cyber Diver News Network. 26 Jan. 2005. Web. 19 Oct. 2009. .

Chan, Norton. "KC3 Invasive and Alien Aquatic Animals/Plants." Personal interview. 23 Oct. 2009.

Harris, Jason. "KC3 Invasive and Alien Land Animals/Plants." Personal interview. 23 Oct. 2009.

Rayson, Ann. Modern history of Hawai'i. Honolulu: Bess, 2004. Print.

"Species found at O?ahu-Hanauma Bay RA." Bishop Museum. Web. 6 Nov. 2009. .

Walsh, W.J. "Fact Sheet: Hawaii's Reef Fishes Are in Steep Decline." Web. 28 Oct. 2009. .

Wilson, Christie. "Divers Target Invasive Species." Web. 6 Oct. 2009.

Zoo-to-You- Island Invaders: Don't let aliens invade Hawaii. Honolulu: Honolulu Zoo Society, 2006. Print.