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Tuesday, January 2, 2001

By Dennis Oda, Star-Bulletin
Kassi Cole, Virginia Moriwake and her husband, UH
research associate Aaron Moriwake, feed the opakapaka
inside the underwater floating cages at Coconut Island.

Fish reserves
may lead to
better angling

A UH researcher looks at protecting
onaga, ehu and opakapaka to make
them more prolific in the future

Sonar system may help save bottom fish

By Helen Altonn

Closed fishing areas to protect endangered snappers could enhance the prized fish stocks in open areas, says bottom-fish researcher Chris Kelley.

University His data is providing clues on how bottom-fish reserves can improve fishing -- "if fishermen would just respect the boundaries and give it a chance," he says.

"The Department of Land and Natural Resources is only interested in making the boundaries work."

Kelley is a Hawaii Undersea Research Laboratory biologist and University of Hawaii Institute of Marine Biology researcher.

He began surveying island waters three years ago to identify bottom-fish habitat sites. Another three-year program began in June with about $500,000 per year from the DLNR and UH.

Prime species of endangered bottom fish are ehu (red snapper) and onaga (long-tailed red snapper), which are down to 3 to 5 percent of their 1955 spawning populations. Opakapaka is nearing endangered status.

Working with HURL's submersible and Randy Cates' 46-foot Australian catamaran, Kelley said he found more areas where ehu exist, but not as many for onaga.

'A work in progress'

He said fishermen were very helpful in providing information about places where they used to catch onaga, but he may have visited them at the wrong time.

Kelley gave DLNR a CD-ROM with all three years' worth of data and records in a Geographic Informational System format.

He combined National Geological Survey sea-floor maps and National Oceanic and Atmospheric Administration nautical charts with GIS images layered with data on the maps.

They show where different fish were seen, their sex and weight, the depth range, bottom topography and other crucial details.

Although the maps are comprehensive, Kelley said it is just the beginning.

"Records will continue to be built," he said.

He said he wants the state to have data on all sites so it can adjust reserve boundaries if warranted.

Walter Ikehara, DLNR aquatic biologist, developed the bottom-fish rules in 2 years of work with fishermen, scientists and fishery managers. A management plan was adopted in 1998.

He said the information Kelley is getting will be useful as the Aquatic Resources Division evaluates the reserves and possible improvements.

The data indicates what the ocean bottom is like and shows "different species seem to have different preferences," Ikehara said.

"Right now, we aren't considering making wholesale changes," he added. "It's still kind of a work in progress."

'Some sites are clearly better'

Ikehara said it is unfortunate that DLNR did not have the kind of information Kelley is collecting when it drafted the bottom-fish management plan.

"We could have made better choices. Some areas are real good hits. Others miss. With the information at the time, it was the best we could do."

The state restricted 19 bottom-fish areas: Five on Oahu, one on Niihau, two on Kauai, two on Molokai, two on Maui, five on the Big Island and two on Penguin Banks.

Kahoolawe, under the Kahoolawe Island Reserve Commission, is a separate part of the state management plan.

By Dennis Oda, Star-Bulletin
Rich Pyle, Bishop Museum underwater photographer, videotapes
Aaron Moriwake inside one of the cages Moriwake designed and
built to raise and breed opakapaka and ehu. The cages float in
the lagoon at the Institute for Marine Biology.

Intentionally or not, the sites have become part of a great experiment, Kelley said.

"No one knows how to create reserves for deep-water snappers. As it turns out, based on data before the reserves and with the survey, the state protected a whole variety of different types of habitats -- pinnacles, walls, or combined, domes and mounds. Sizes differ.

"So what you've got is this big experiment. Some (sites) are clearly better."

Kelley had access in August to a side-scan sonar tow-fish that was loaned to him by the University of Mississippi.

He used it to explore opakapaka nursing grounds of concern to the National Marine Fisheries Service and the Western Pacific Fishery Management Council.

NMFS researcher Frank Parrish had concluded that opaka juveniles, unlike adults, like soft mud, Kelley said.

Side-scan sonar mapping off Molokai, Lanai, Kaneohe and Kailua proved Parrish was right, Kelley said. "They like muddy bottoms. We don't see anything else going on."

Niihau 'has huge promise'

Kelley said the Kahoolawe bottom-fish reserve is interesting because it has been partially or wholly closed since the 1940s.

"It has given us an idea what to expect from reserves in the right areas. The channel next to Kahoolawe (outside the reserve) is one of the most productive bottom fisheries in the state."

The reserve can seed depleted areas through breeding, or fish can migrate in and out of the reserve -- "a phenomenon called adult spillover," Kelley said.

In February he did multibeam mapping aboard the University of Washington ship R.V. Thomas Thompson and mapped the entire Alalakeiki Channel between Kahoolawe and Maui.

"Tons of onaga" were detected along the wall of the reserve, indicating the open areas possibly could be enhanced with fish seed or migrations with a few boundary adjustments, Kelley said.

WESTPAC also had asked his team to look for hapuupuu (grouper or sea bass), which he found on the boundary, he said.

Kelley said the Niihau reserve "has huge promise." It was created because of a large underwater guyot or mound and is a well-known bottom-fishing site. Fishermen are unhappy that it was selected for a reserve, but it has a good breeding population, he said.

On the other side of it are two fishing spots known as the South Point and Pueo Point Pinnacles. A very deep area between the banks and South Point Pinnacle is probably a barrier for the fish migrating back and forth, he said.

However, fish possibly are moving back and forth between the banks and Pueo Point Pinnacle via a rock or habitat bridge, he said.

If the reserve boundaries of Pueo Point were adjusted, he said, "This may become a really dynamite fishing spot."

A lot more needs to be known

The multibeam swath mapping provided an "incredibly detailed map" showing whether the bottom was rocky, sandy or muddy, he said, noting that adult snappers like rocky areas.

At Makapuu Point, he said, the reserve boundary runs across the top of mounds.

"If the state wants to adjust the boundary, they can see more clearly where the fish are."

But he said, "If we're going to create a reserve that will help enhance fisheries, we have to know an awful lot about what's going on."

For instance: How long do larvae stay in plankton? What are the currents like? How much time do larvae spend in currents? What paths do they take, so scientists can predict where they are likely to settle?

Recovery of a depleted reserve that previously had good fishing could possibly be jump-started by putting stock in it, Kelley said.

He has six submersible dives scheduled next year and plans to use nonlethal fishing techniques to see if the fish populations can be assessed in the reserves with sonar acoustics.

Kelley also is involved in research at the UH Institute of Marine Biology at Coconut Island to try to raise endangered snappers in hatchery conditions.

Ka Leo O Hawaii
University of Hawaii

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