Environmental correlates of blue and fin whale call detections in the North Pacific Ocean from 1997 to 2002

A 6 yr time series of blue whale Balaenoptera musculus and fin whale B. physalus call detections in the North Pacific Ocean was correlated with 3 oceanographic variables (sea-surface temperature, chlorophyll a concentration, and mixed layer depth), to investigate the broad-scale calling behavior of these species. Monthly values for satellite-derived oceanographic data and whale call data were compared for 4 regions (30 degrees longitude by 15 degrees of latitude) encompassing the whole subarctic North Pacific and an area in the temperate northeastern Pacific. To determine predictive models for whale call occurrence, generalized linear models were used to determine which, if any, oceanographic variables might influence whale calling behavior over such broad space and time scales. Sea-surface temperature was the best oceanographic variable for predicting whale call detections for both species and all regions.