Male sperm whales (Physeter macrocephalus) are known to interact with and

depredate from commercial longline fishing vessels targeting sablefish

(Anoplopoma fimbria) in the Gulf of Alaska (GOA). This study aims to better

understand their movement patterns and diving behavior in this region, and in

relation to depredation behavior. Between 2007 and 2016 a total of 33 satellite

tags were deployed on sperm whales interacting with fishing vessels in the

eastern GOA. A subset of these tags also collected dive characteristics. We used

state space models to interpolate hourly positions from tags and estimate

behavioral state from 29 usable tag records, 14 of which had associated dive

information. Whales exhibited slower horizontal movement (1.4 km/hr) within

GOA waters compared to south of the GOA (5.5 km/hr), indicating tagged whales

sped up when they left the region. Behavioral states indicated primarily foraging

behavior (82% of locations) in the GOA and primarily transiting behavior (74% of

locations) when whales left the GOA. Dive data showed average ( ± Standard

Deviation) maximum dive depths of 396 m ( ± 166), and dive durations of 32 min

(± 9). Generalized additive models indicated that dives were significantly deeper

and longer during the daytime than dawn, dusk, or nighttime, and dives were

significantly deeper and shorter during quarter moons, when tidal currents are

weakest. Maximum dive depth decreased in areas of higher sablefish CPUE,

suggesting a potential link between the sablefish fishery and depredation

behavior. As seafloor depth increased, up to 800 m, dives became deeper,

indicating that whales were likely targeting both bathypelagic and mesopelagic

prey. This highlights the importance of the GOA continental slope as a foraging

ground for male sperm whales. This enhanced understanding of sperm whale

foraging ecology informs management and conservation efforts in high latitude

foraging grounds.