Predictive Models of Cetacean Densities in the Hawaiian Islands EEZ, 2019

A predictive habitat-based model of humpback whale (Megaptera novaeangliae) density for waters within the Hawaiian Islands Exclusive Economic Zone (EEZ) was developed based on systematic ship survey data collected in waters of the Main Hawaiian Islands in February 2009. Potential habitat variables included bathymetric depth and a suite of dynamic outputs from the Hybrid Coordinate Ocean Model. The final habitat model exhibited high explanatory power based on established metrics and comparison of model-predicted absolute density to observed patterns of relative density around the Main Hawaiian Islands. The model was then used to create spatial predictions of humpback whale density and measures of uncertainty for the entire Hawaiian Islands EEZ. Predictions outside the original survey area were validated based on previously published predictions of relative density throughout the Northwestern Hawaiian Islands. The resulting model provides spatially explicit density predictions at a scale of approximately 9km x 9km kilometers and provides a tool for assessing potential impacts to humpback whales within the Hawaiian Islands EEZ.