Seasonal Patterns of Fin Whale Calls in the Northeast Pacific

Abstract

After a century of commercial whaling fin whales are currently listed as a vulnerable species and are increasingly at risk of endangerment from new anthropogenic noise, vessel traffic, entanglement, and habitat degradation. Fin whales have been observed to congregate near areas of high bathymetric relief along the U.S. Atlantic and the Gulf of Mexico. Visualization of patterns and gross call differences of fin whales in the Northeast Pacific were made to analyze seasonal trends in call counts at two sites over five years. Data was collected with a low-frequency hydrophone and a vertical seismometer from a cabled observatory at the southern foot of a submarine seamount ~475 km from the Oregon coast, and adjacent to the continental slope ~125 km from the Oregon coast respectively. Fin whale calls were identified and analyzed with an algorithm for automatic detection. The trend of detections shows the fin whale calling season appears earlier in the year in greater magnitude on average closer to the continental shelf, with presence in more pelagic waters following in the subsequent two to three months. This trend may be correlated to the behavioral movement and bathymetric preference in the Northeast Pacific fin whale population.