Tuesday, August 25, 2009

Sonar work a beaming success

Last week the Large Pelagics Research Center conducted a research project with the Center for Coastal Ocean Mapping. The project, funded through the Northeast Consortium, is a pilot project to determine the feasibility of estimating biomass of juvenile Atlantic bluefin schools in the Gulf of Maine using high frequency multibeam sonar. Captain Billy (Hollywood) Muniz along with spotter pilots Mark Brochu, Mark Avila and George Purmont were all involved in data collection. In total, we spent 5 days on Stellwagen Bank and in Cape Cod Bay imaging juvenile bluefin tuna.

Sam and Michelle setting up the sonar system

Sam and Tom lowering the sonar head

A major objecive is that in ABFT stock assessments, any estimate of recent recruitment is highly dependent upon assumptions or estimates of the selectivity of the five youngest age classes in the most recent year of the stock assessment . We hope to develop new approaches for developing indices of abundance, and/ or improve the understanding of population dynamics of juveniles. A direct assessment of juveniles with sonar techniques (and aerial reconnaissance) has the potential to provide critically needed information for stock assessments and managers.

Mark Brochu found the fish for us and took aerial images

Captain Muniz

Thanks to the presence of fish, the sonar work was a great success. The data collected (about 1MB/second of imaging!) will keep us busy this fall and winter!

Post and photos Ben Galuardi, Research Scientist, Large Pelagics Research Lab

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