Impacts of marine vessels on whale surfacing, behavior, and detection
Human activities impact wildlife in a variety of ways - both indirectly (through influences such habitat loss and destabilization or predator-prey dynamics) and directly (through influences such as direct mortality). With global distribution, baleen whales are no stranger to impact from humans. Whaling decimated many species and populations up through the 20th century. While the moratorium on commercial whaling in 1986 has allowed baleen whales to recover to varying degrees, many populations still face a myriad of pressures, including indirect and direct disturbance (death) due to overlapping ocean use and collisions with large ships, and are of great conservation concern.
Glacier Bay National Park and Preserve in southeast Alaska is an important feeding area for migratory humpback whales from late spring to early fall and is also a popular destination for large cruise ships during the summer months. This overlap in wildlife and human use of a common area results in many ship-whale encounters within cruise ship routes between ports. We used this natural set up to investigate facets human activity on whales that could be informative for mariners in avoiding collisions.
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How detectable are whales from large vessels and how do conditions during a ship-whale encounter, such as weather, whale behavior and distance between whale and ship, impact the probability of detection?
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What are the patterns of individual whale's surfacing events during a ship-whale encounter and do these patterns change given the proximity and relative bearing of the encounter?
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Do whales change behavior (defined as it can be visually-assessed from a vessel) in response to a close encounter?
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How do the numbers of collisions simulated with estimated surfacings patterns vary with changes in ship speed along a designated route?
