Harbor Porpoise Data Collected by Pacific Biodiversity Institute

The information below was collected at Burrows Pass from the bluff at Washington Park in Anacortes for the years 2011 through 2013. The charts tell what fraction of the time porpoises were present for each month.

harbor porpoise observation data

Data collected by observations includes: number of porpoises, average location of the porpoises for each ten minute interval, behavior, a note of other species present, weather information and the time of the observation. The “unit of effort” is the ten minute interval. Observers watch for a total duration of two hours under most circumstances.

The observation data for 2009 through 2013 has not been analyzed with reference to the sighting location of the animal. The data was simply analyzed based on whether porpoise were present or not present and the number of porpoise that were present.

The data is analyzed to compute fraction time present by month and the number of porpoise present averaged by day for each month. A standard deviation is calculated for these averages.

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