Humpback whale (Megaptera novaeangliae)

Mortality from collisions with vessels is one of the main human causes of death for large whales. Ship strikes are rarely witnessed and the distribution of strike risk and estimates of mortality remain uncertain at best. We estimated ship strike mortality for blue humpback and fin whales in U.S. West Coast waters using a novel application of a naval encounter model. Mortality estimates from the model were far higher than current minimum estimates derived from stranding records and are closer to extrapolations adjusted for detection probabilities of dead whales.

Managing marine species effectively requires spatially and temporally explicit knowledge of their density and distribution. Habitat-based density models, a type of species distribution model (SDM) that uses habitat covariates to estimate species density and distribution patterns, are increasingly used for marine management and conservation because they provide a tool for assessing potential impacts (e.g., from fishery bycatch, ship strikes, anthropogenic sound) over a variety of spatial and temporal scales.

Based on past genetic and photo-identification data, humpback whales in the North Pacific show site fidelity to distinct feeding areas to which they return annually including an area that encompasses the waters off Washington and southern British Columbia. This represents one of the smaller North Pacific feeding areas both geographically and numerically. Combined with its transboundary status and busy shipping-lane traffic through this area from both US and Canada ports, this is an important but complicated area for management.

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