[MARMAM] NEW 2023 Glacier Bay, Alaska humpback whale report available

Neilson, Janet L Janet_Neilson at nps.gov
Fri Mar 10 11:10:13 PST 2023

The following report summarizing humpback whale monitoring results from 2022 is now available:

Neilson, J.L., C.M. Gabriele, and L.E. McCaslin. 2023. Glacier Bay & Icy Strait Humpback Whale Population Monitoring: 2022 Update. National Park Service Resource Brief, Gustavus, Alaska.

Glacier Bay & Icy Strait Humpback Whale Population Monitoring: 2022 Update (nps.gov)<https://irma.nps.gov/DataStore/DownloadFile/682953>

[1.7 MB, 8 pages]

The 2023 field season (our 39th year of monitoring) will be underway soon!


  *   The total number of whales in Glacier Bay-Icy Strait (GB-IS) was similar to 2021. In Glacier Bay, abundance increased compared to 2021, while in Icy Strait, abundance decreased.

  *   Thirty-one of 66 adult whales (47%) with a history of strong site fidelity to GB-IS were missing and most are presumed to have died during or after the 2014-2016 Northeast Pacific marine heatwave (PMH).

  *   We documented six mother/calf pairs and a declining crude birth rate (CBR) since 2020 (2020: 7.4%; 2021: 6.5%, 2022: 3.6%). Although calf production appeared to be rebounding in 2020 following sharp declines during and after the PMH, it remains far below the pre-PMH mean CBR of 9.1%.

  *   Juvenile survival appears to be increasing after an abrupt decline during and after the PMH.

  *   Relatively high residency and low transience rates in 2019-2022 presumably reflect favorable feeding conditions in GB-IS in contrast to PMH years.

  *   The rate of emaciation (16%) appeared to be lower in 2022 than in recent years and reverses a pattern of increasing emaciation.

  *   In February 2022, adult female #235/”Spot” (age ≥49) was found dead near Angoon and a necropsy revealed that she likely died after being hit by a large vessel.

  *   We opportunistically documented forage fish, especially sand lance, but annual forage fish monitoring is needed to systematically assess whale prey trends.

Janet Neilson
Humpback Whale Monitoring Program
Glacier Bay National Park & Preserve
PO Box 140
Gustavus, AK 99826

Xunaa Káawu Aaní áwé yéi xat yatee ka ax’ yéi jixané

I live and work in Huna Tlingit Homeland.

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