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Published byPhilippa Francis Modified over 9 years ago
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Northern copepod biomass anomalies and copepod species richness as indicators of trophic structure in the NCC Bill Peterson, Senior Scientist NOAA Fisheries Jennifer Fisher, CIMRS/Oregon State Univ Newport OR
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We have been sampling the Newport Line every two weeks for 19.5 years to try to understand: a) the causes of interannual variability in plankton b) how this variability translates into differences in food web structure upon which juvenile fish feed such as salmon, sardines, sablefish and rockfish
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Circulation off the Pacific Northwest 1. Subarctic Coastal Currents bring cold water and ”northern” copepod species to the N. California Current 2. A weak California Current, onshore flow of the West Wind Drift and Davidson Current (in winter) brings subtropical water and subtropical “southern” copepod species to the NCC = increased species richness 3. Therefore, food chain structure is affected by the source waters which feed the California Current Different climate modes and associated differences in transport are important for three reasons:
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Data on the abundance or biomass of ‘northern’ copepods and species richness is important because… Warm-water subtropical southern species- (from offshore OR and S. California) are small in size and have minimal high energy wax ester lipid depots Cold-water northern species – (boreal coastal species) are large and store high-energy wax esters as an over- wintering strategy Therefore, significantly different food chains result from changes in transport A fat _____ is a happy ______
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PDO and Northern Copepod Anomaly
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PDO and Copepod Species Richness Anomaly Subtropical species Boreal species
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Copepod indices vs salmon returns
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Northern copepod anomaly vs Sardine and Sablefish recruitment
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Climate modes: PDO, ONI, HFCCTI, NPGO CC had lower flows in 03-07, and 10 CC had higher flows in 02, 08-09 and 10-13 Matches PDO closely(except 2014)
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