Scientists find the fish are good
indicators of ecological conditions
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By Helen Altonn
haltonn@starbulletin.com
Scientists learned a lot about coral reefs at Kahoolawe and developed a method of monitoring reefs elsewhere by observing colorful butterflyfish.
Ernest S. Reese, retired University of Hawaii zoology professor, said he focused on butterflyfishes during 20 years of research on behavior of coral reef fishes with graduate students.
"It dawned on me some years ago that butterflyfish are good indicators of ecological conditions on coral reefs."
He said they meet all the criteria for an "indicator species" because they spend their whole life in a small area on corals. Some eat plankton, algae and bottom animals but other species eat coral and "the coral feeders are in pairs mating," Reese said.
"They're easy to identify. You don't have to count fins and scales. If their habitat changes, this is reflected in the distribution, abundance and behavior of resident butterflyfishes."
The National Oceanic and Atmospheric Administration was looking for innovative ideas for management and conservation of coral reefs, and Reese proposed a project at Kahoolawe.
Michael Crosby, member of NOAA's Science Advisory Board, joined him in field tests of the butterflyfish species Chaetodon multicinctus on Kahoolawe reefs from 1992-1997.
The Chaetodontidae family of butterflyfishes is common in all tropical seas, through the Pacific to the Red Sea, Reese said.
The scientists studied two Kahoolawe sites with permission from the Kahoolawe Island Reserve Commission: Hakioawa, a pristine area with high coral cover, many butterfly fishes and relatively little sedimentation, and Kuheia, heavily degraded from sedimentation.
They found corals and fish returning to the damaged areas, Reese said. "The reef is restoring itself."
They developed a simple monitoring method that they also tested on coral reefs at Molokini Island and other locations in Hawaii. Reese said it's sensitive to reef improvement and deterioration and can be used in Third World countries without trained personnel.
The scientists produced a manual and conducted training sessions on the system in Samoa, Guam and Saipan, all of which have had coral reef damage, Reese said.
They also took their method to a Middle East Regional Science Symposium and Workshop because of concern about preserving coral reefs in that region.
It's now in use or being tried out at various places in the Pacific, India, the Seychelle Islands, Jordan and Israel, Reese said.
"It isn't perfect yet; it's still being developed," he said, acknowledging that there are critics out there. "Critics say if you want to know what coral is doing, look at them directly."
However, use of indicator species is less expensive, less complex and doesn't require scientifically trained personnel, archiving, storage and analysis of samples, he said.
Observing the fishes' behavior can provide early warning of changes occurring, whether destruction or recovery, he said.
"They are totally dependent on the reef. If they try to expand their territory, we know something is wrong." If they try to expand to get more food, they encroach on neighboring fish who fight back, he said.
Only one or two technicians or divers and a supervisor are needed for a monitoring project, he said. "All they have to do is identify a couple fish ... They don't even have to know scientific names."
They can snorkel in shallow nearshore reefs and work from a boat and scuba dive in deeper reefs, he said.
Using volunteers is beneficial, the scientists said in a report on their project, because they "learn to appreciate the subtle workings and interactions of the coral reef ecosystem."
