Now, researchers at the University of California, Santa Cruz, are working out the details of the oceanographic conditions that determine how and when juvenile rockfish return to the kelp beds. New instruments that provide detailed information about distinct layers and movements of ocean waters along the coast are playing a key role in this effort.
"Only now do we have the technology to see the fine-scale thermal and density structure of the ocean and make these connections between specific oceanographic events and the biology of fish and other organisms," said Margaret McManus, an assistant professor of ocean sciences at UCSC.
UCSC graduate student Arnold Ammann found that juvenile rockfish return to their nearshore habitats in pulses, the timing of which depends on the species. Linking these patterns with oceanographic observations, McManus and her collaborators found that some species are brought in with the periodic upwelling of cold, deep water, while others come in when the upwelling subsides. In addition, McManus has found that fish larvae and other plankton are often concentrated in previously undetected thin layers of ocean water that extend for miles and persist for days at a time.
"We have found concentrations of organisms in these layers five times higher than in surrounding waters," McManus said.
McManus will present the group's findings in a symposium, "Opening the
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Contact: Tim Stephens
stephens@ucsc.edu
831-459-2495
University of California - Santa Cruz
15-Feb-2003