August 10, 2021, by admin

Janet Neilson from the Humpback Whale Monitoring Program Glacier Bay National Park & Preserve recently shared their 2020 findings with SSSC. Janet was a speaker at a Sitka Whalefest and was excited to share about the come back of humpback whales in Glacier Bay.

KEY FINDINGS FROM 2020: 

• The Glacier Bay-Icy Strait (GB-IS) humpback whale population is increasing following significant declines attributed to ecological disruption from the 2014-2016 Northeast Pacific marine heatwave.
• Whale abundance remains at least 25% lower than at its peak in 2013 and was comparable to what we observed in 2008.
• Twelve mother/calf pairs led to a crude birth rate (CBR) of 7.5%, which is a positive trend compared to recent years, yet below average compared to 1985-2013 (average CBR 9.3%).
• Increased whale abundance in 2020 was driven by a relatively high number of calves (n = 12) and a 13% increase in the number of whales in IS, while abundance in GB remained similar to 2019.
• Twenty-nine of 66 whales (44%) with a history of strong site fidelity to GB-IS remain missing and increased mortality due to the heatwave seems likely.
• Opportunistic forage fish observations suggest a continuation of improved feeding conditions in recent years, yet many whales (21%) appeared emaciated, including nine mothers and three of their calves.
• During and after the heatwave, whales were more often alone than in pairs or larger groups, and they were much more likely to be feeding than other behaviors.
• Temporary whale waters and reduced speed limits were not needed in 2020 due to low whale use of lower GB and reduced vessel traffic (~45% decline compared to recent years due to the COVID-19 pandemic). 

The Full report can be downloaded here https://irma.nps.gov/DataStore/DownloadFile/662742

The 2021 field season (our 37th year of monitoring) is well underway with 11 mother/calf pairs documented in GB-IS to date. We look forward to sharing the 2021 monitoring results with you in the coming year!