The following report summarizing humpback whale monitoring results from 2024 is now available: Neilson, J.L., C.M. Gabriele, and H.K. Hoffbauer. 2025. Glacier Bay & Icy Strait Humpback Whale Population Monitoring: 2024 Update. National Park Service Resource Brief, Gustavus, Alaska. https://www.nps.gov/glba/learn/nature/upload/Neilson_etal_2024_Humpback_Whal... [7.8 MB, 10 pages] KEY FINDINGS FROM 2024: * Whale abundance in Glacier Bay-Icy Strait increased after a four-year period (2020-2023) in which abundance had remained relatively flat, however numbers remain ~30% lower than before the 2014- 2016 NE Pacific marine heatwave. * We documented a “baby boom” with a record-high number of mother/calf pairs (n = 24). This year’s crude birth rate (12.8%) was one of the highest on record; not only reaching, but exceeding, the pre-marine heatwave mean (9.2%). * Several of this year’s mothers had unusually long calving intervals (9-11 years) and seven females had their first known calves at ages much older than the average for this population. These delays are likely attributable to the NE Pacific marine heatwave and its aftermath. * For the second year in a row, we received several reports of killer whales “attacking” or “harassing” humpback whales and in June a humpback calf acquired injuries consistent with a killer whale predation attempt, which is extremely rare in Southeast Alaska. * An unusually high number of whale-vessel collisions were reported in Icy Strait. In addition, two humpback whales were found dead: * 1) an unidentified juvenile male near Elfin Cove had injuries consistent with a vessel collision and 2) 23-year-old pregnant female #1731 had injuries suggestive of blunt force trauma but her cause of death could not be confirmed. -- Janet Neilson Humpback Whale Monitoring Program Glacier Bay National Park & Preserve PO Box 140 Gustavus, AK 99826 907-697-2658 Xunaa Káawu Aaní áwé yéi xat yatee ka ax’ yéi jixané I live and work in Huna Łingít Homeland.