Plankton Population Variability Determined From a Ship of Opportunity Transect Through the Aleutians

Continuous Plankton Recorders have been towed behind commercial ships on their transit from the north American west coast to Asia, a great circle route which transits through the Aleutian Islands. The ship almost always enters through Unimak Pass, with the western exit being more variable but usually around Agattu or Attu Islands. Sampling began in 2000 and since 2002 has sampled spring, summer and fall each year. The data collected provide taxonomically resolved abundance information on the base of the food chain, specifically hard-shelled phytoplankton and robust zooplankton. For the last 10 years the CPR has been instrumented to also collect temperature, salinity and chlorophyll fluorescence data along the transect. With a 16 year plankton time series now available, which includes warm and cool years experienced in the region, the data can be used to assess the impacts of climate variability on the plankton. This presentation will provide details on the project and an overview of the data, including regional and interannual variability so far revealed. The intention of the presentation is to increase awareness of this project which could provide data that are of use to resource managers in the region.