Temporal variations in humpback whale (Megaptera novaeangliae) song in Monterey Bay National Marine Sanctuary, northeast Pacific

Using two years of nearly continuous recordings from Monterey Bay National Marine Sanctuary, August 2015 through July 2017, variations in humpback whale song are examined on diel, seasonal, and interannual time scales. The cabled hydrophone is in humpback feeding and migratory habitat at 36.7128°N, 122.186°W. Diel analyses show 69% of song during night, 23% during day, and 8% during dusk or dawn. Seasonal analyses show song absence during summer (June–August), emergence during fall (September–October), peak during late fall/winter (November–January), and highly variable detection during spring (February–May). During both years u003e80% of song occurred during the November–January peak. Song detection within a month reached a maximum of 58% of the time during November 2016. Song length increased (p u003c 0.01) month-to-month from the start in fall through the end of the peak in January. The months of maximum song occurrence coincide with declining visual sighting of humpbacks within Monterey Bay, consistent with s...