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Continuing a Conservation Science Legacy: 40 Years of Monitoring Hawaiian Monk Seals

September 06, 2023

For more than 40 years, our monitoring and recovery work in the Papahānaumokuākea Marine National Monument has been critical to guiding the protection of Hawaiian monk seals.

A rainbow appears over the shoreline with a row of green wall tents, two boats moored offshore, and dozens of albatross chicks sitting on the beach. The Hawaiian monk seal Assessment and Recovery Camp at the remote atoll of Manawai. Credit: NOAA Fisheries/Jessica Bohlander (Permit # 848-1695)

We have monitored monk seals in the Papahānaumokuākea Marine National Monument for 4 decades. This has resulted in one of the most comprehensive and long-running datasets in conservation science to guide the recovery of this Hawaiian seal. Now, their gradual population growth is allowing us to continue this important work in more efficient ways!

A Large Undertaking

The Endangered Species Act designated the Hawaiian monk seal as endangered in 1976. The historical rapid decline of the Hawaiian monk seal population urged immediate action to help preserve the species. In the early 1980s, NOAA developed a standardized monitoring program to assess the Hawaiian monk seal population in the monument. This created the foundation of the work NOAA continues to do to this day. 

During a standard Hawaiian monk seal assessment and recovery camp season, camps are established for 3 to 4 months at five sites: Lalo (French Frigate Shoals), Kamole (Laysan), Kapou (Lisianski), Manawai (Pearl and Hermes Reef), and Hōlanikū (Kure Atoll). Given the remoteness of the monument, these camps are a massive logistical undertaking. They require a significant seasonal hiring effort to staff all camps, and roundtrip voyages aboard large research vessels.  

While at camp, field biologists perform important work such as: 

  • Conducting survival-enhancing interventions like disentangling seals from marine debris, and treating abscesses
  • Monitoring births to maintain data crucial to understanding reproductive rates of the population
  • Tagging weaned pups to identify individuals and track survival
  • Documenting threats to seal survival
  • Identifying marked individuals for population counts and tracking (with a priority on juvenile individuals that contribute most to survival estimates)
Hawaiian monk seal research program team members use transit time on the ship to make final gear preparations and test communications equipment while smiling for the camera.
It takes a lot of people and gear to make a field camp happen in the remote Papahānaumokuākea Marine National Monument! Credit: NOAA Fisheries (Permit # PMNM-2023-001)

Scaling Back While Moving Forward 

The Hawaiian monk seal population has slowly and steadily increased over the last decade. As a result, the team evaluated decades of data to strategize what future camps might look like and make the best plan moving forward. The data showed that, at most sites, deploying teams for a few weeks after the peak of summer pupping would suffice. It would allow teams to tag almost all newborn pups and likely identify 80 to 95 percent of the older seals.

Identification tags on each of the hind flippers of a Hawaiian monk seal pup.
NOAA field biologists work hard to give each weaned pup a set of identification tags on their hind flippers. These tags are essential to identifying individual seals to track survival rates and numbers in the population. Credit: NOAA Fisheries (Permit #10137)

Assessment and recovery camps can now be adjusted to continue essential objectives while lightening the load on staffing and logistics. Throughout August and September, the team is conducting a 30-day research mission and establishing short (16- to 20-day) camps at Kamole, Kapou, and Manawai. We are relying heavily on partnerships with other agencies conducting year-round work at the following locations:

  • Hōlanikū: State of Hawai‘i Department of Land and Natural Resources
  • Kuaihelani (Midway Atoll): U.S. Fish and Wildlife Service 
  • Nihoa, Kamole, and Kapou: Papahānaumokuākea Marine Debris Project and U.S. Fish and Wildlife Service

In future years, we will alternate between larger and lighter assessment and recovery camp seasons as determined by the data. This approach will allow us to direct people and resources to other areas like growing the monk seal population in the main Hawaiian Islands.

Two people carrying backpacks are hiking on the beach along the shoreline.
After conducting rapid surveys for 2 days, in partnership with the Department of Land and Natural Resources team at Hōlanikū, seal researchers begin surveys at Manawai, where they will be camping for 16 days. Credit: NOAA Fisheries/Christy Kozama (Permits: NMFS 22677, PMNM-2023-001)

An Exception to the Rule: Lalo 

Lalo is an important exception to this lighter approach. Lalo is a large and complex atoll, so surveys take a lot more effort and time. Seals at Lalo make up 20 percent of the population in the monument, making it a significant location for research and monitoring. Pups at Lalo tend to be born later in the year, so it would be difficult to tag the majority of pups here. Lalo is a dangerous place for monk seals (especially young seals). There is aging infrastructure from an old military installation on Tern Island and an unusually high rate of shark predation. While many sites can have a shortened camp without detrimental impacts, Lalo needs a full-length camp every year. 

Lalo is also an important nesting area for Hawaiian green sea turtles. We set up camp on Lalo in May and are working through October.

Two field biologists carry a seal pup to move it to a safer location.
Hawaiian monk seals at Lalo face a number of threats including high shark predation on seal pups. NOAA field biologists help safeguard the population by conducting numerous life-saving interventions. Here a seal pup is being moved from an islet with frequent shark attacks to one with lower predation. Credit: NOAA Fisheries (Permit # 848-1695)

Making Preparations To Monitor Monk Seals 

We are excited to continue this important conservation science legacy with the goal of supporting the continued growth and conservation of Hawaiian monk seals. Mahalo to our partners and community for your continued support. This 30-day research mission is underway. Follow along for updates and news!