March 27, 2009

Sensor Studies Schools Of Fish

Conservationists are now able to watch the movement of large groups of fish as they gather into sandbanks.

According to a report in Friday's edition of the journal Science, researchers were able to watch Atlantic herring gather off Georges Bank near Cape Cod, Mass., where they spawn during the night.

At dawn, the mass of fish return to the deep and scatter.

According to Nicholas C. Makris, professor of mechanical and ocean engineering at the Massachusetts Institute of Technology, the team used a system called Ocean Acoustic Waveguide Remote Sensing to watch the fish across a 25 mile span.

Previous studies were only able to cover very small areas.

According to Makris, the difference is like being able to see an entire movie, compared to seeing a single pixel.

The work, conducted using a novel imaging technique, "provides information essential to the conservation of marine ecosystems that vast oceanic fish shoals inhabit," wrote the researchers.

Scientists say it confirms theories about the behavior of large groups of animals in general, from bird flocks to locust swarms; until now those theories had only been predicted through theoretical investigations like computer simulations and laboratory experiments.

"Understanding these processes could be relevant to the management of ocean fisheries practices at a time when many schooling oceanic fish species are being over fished," said zoology professor Robert Blake of the University of British Columbia.

John K. Horne, a professor at the School of Aquatic and Fishery Sciences, University of Washington noted that the descriptions of fish distributions "will increase our understanding of behavior and habitat use."

Makris sees potential in using OAWRS to better monitor and conserve populations of fish.

Ron O'Dor, scientist of the Census of Marine Life (CoML), said, "OAWRS allows us to gather information such as geographical distributions, abundance and behavior of fish shoals and to better understand what constitutes healthy fish populations ... which can be implemented by policymakers to better monitor and improve conservation of fish stocks."

CoML is an international scientific collaboration focused on a ten year plan to assess the diversity, distribution and abundance of marine life in the oceans.

The group plans to release the first Census of Marine Life in 2010.

The research was supported by the federal National Oceanographic Partnership Program, the Office of Naval Research and the Alfred P. Sloan Foundation.


Image 2: Map of the area off Georges Bank studied by MIT engineers and colleagues. Image / Makris Lab, MIT; Ratilal Lab, NU

Image 3: Sequence of images showing initiation of a massive fish shoal. Graphic / Makris Lab, MIT; Ratilal Lab, NU


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