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February 2011 Issue

Thriving 'Middle Light' Reefs Found in Puerto Rico
NOAA-funded scientists have found extensive and biologically diverse coral ecosystems occurring at depths between 100 and 500 feet within a 12-mile span off the southwestern coast of Puerto Rico.

"We had no idea how extensive, vibrant and diverse these mesophotic coral ecosystems are off La Parguera," said Richard Appeldoorn, lead principal investigator at the University of Puerto Rico, Mayaguez.

With the overall health of shallow coral reefs and the abundance of reef fish in Puerto Rico in decline, the scientists said these findings bring hope that deeper fish stocks may help to replenish stocks on shallower reefs.

These mesophotic ecosystems are the deepest of the light-dependent coral reefs. Too deep for exploration with traditional scuba gear, these reefs have remained largely unexplored because of the cost and technical difficulty of reaching them. Recent advances in diving techniques allowed the scientists to safely dive and conduct this survey.

"At mesophotic depths in Puerto Rico, scientists are seeing fish species that were once common inhabitants of shallow reefs, such as groupers, snappers and reef sharks," said Kimberly Puglise of NOAA's Center for Sponsored Coastal Ocean Research, which funded the study. "These reefs stand in stark contrast to declining shallow-water reefs in the same area."

Because of the potential of mesophotic reefs to restore depleted fish stocks, local managers are looking carefully at added protections.

"We recognize the need to extend protections to mesophotic coral ecosystems in Puerto Rico, and the information being provided by this research is key to making that happen," said Ernesto Diaz, director of Puerto Rico's Coastal Zone Management Program.

Drifting Fish Larvae Help Marine Reserves Rebuild, Study Finds
Marine ecologists at Oregon State University (OSU) have shown for the first time that tiny fish larvae can drift with ocean currents and "reseed" fish stocks more than 100 miles away.

The findings add credibility to what scientists have believed for some time but had been unable to directly document. The study also provides a significant demonstration of the ability of marine reserves to rebuild fishery stocks in areas outside the reserves.

The research, conducted in Hawaii, was recently published in PLoS One.

"We already know that marine reserves will grow larger fish and some of them will leave that specific area, what we call spillover," said Mark Hixon, a professor of marine biology at OSU. "Now we've clearly shown that fish larvae that were spawned inside marine reserves can drift with currents and replenish fished areas long distances away."

Since spillover has now been observed, the study will resolve some skepticism about reserves' usefulness, Hixon said. The findings were based on the creation in 1999 of nine marine protected areas on the west coast of the "big island" of Hawaii. These areas were set up in the face of the decline of a tropical fish called yellow tang, which formed the basis for an important trade in the aquarium industry.

"This fishery was facing collapse about 10 years ago," Hixon said. "Now, after the creation of marine reserves, the fishery is doing well."

The yellow tang was an ideal fish to help answer the question of larval dispersal, because once its larvae settle onto a reef and begin to grow, they are not migratory and live in a home range about half a mile in diameter. If the fish are going to move any significant distance from their birthplace, it would have to be in larval form, drifting with the currents for up to two months.

Mark Christie, an OSU postdoctoral research associate and lead author of the study, developed some new approaches in DNA fingerprinting and sophisticated statistical analysis that were able to match juvenile fish with their parents, wherever they may have been from. In field research from 2006, the scientists performed genetic and statistical analyses on 1,073 juvenile and adult fish. They found evidence that many healthy juvenile fish had spawned from parents long distances away, up to 114 miles, including some from marine protected areas.

Sea Grant Awards $394,000 To Breed a Bigger, Better Oyster
Two University of Southern California (USC) biology professors and a California Sea Grant marine advisor have been awarded $394,000 in a national aquaculture research competition sponsored by NOAA Sea Grant.

The two-year award will fund genetic studies and field tests of a newly developed double-hybrid Pacific oyster that the biologists believe can transform the West Coast's $72-million-a-year oyster growing industry.

The new oyster, 15 years in the making, is produced through a two-stage cross-breeding process that improves growth, size and health to its offspring, said the project's leader, USC biology professor Dennis Hedgecock. In small-scale experiments funded by the U.S. Department of Agriculture, the first generation hybrid oyster was shown to grow twice as fast as the industry standard, meaning that farm yields could also potentially double.

The NOAA Sea Grant award will allow Hedgecock and grant co-recipient Donal Manahan, also a biology professor at USC, to identify genes and metabolic processes responsible for hybrid vigor in the oyster and to use what is learned to develop a tag for identifying, within the first few hours of birth, offspring with desired traits.

This early-detection tool will enable researchers to continue experimenting with breeding bigger Pacific oysters rapidly, without having to wait two years for the oysters to reach maturity and undergo normal testing.

The oyster species selected for the breeding program, Crassostrea gigas, accounts for about 95 percent of the West Coast's cultured oyster product and about 98 percent of total global production.

Paul Olin, an aquaculture specialist and marine advisor with California Sea Grant, is overseeing the soon-to-begin farm trials to document the oyster's performance under in-situ conditions representative of California's coastal climates. The Hog Island Oyster Co. (Marshall, California), Grassy Bar Oyster Co. (Cayucos, California) and Carlsbad Aquafarm (San Diego, California) are participating in trials.


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