The Captive Care and Release Research Project Seeks to Aid Recovery of the Endangered Hawaiian Monk Seal
![Hawaii monk seal](img/monkseal19.jpg)
The endangered Hawaiian monk seal, a biological treasure unique to the Hawaiian Archipelago, is in crisis. Despite living mostly in the now relatively protected environment of the Northwestern Hawaiian Islands, the monk seal population has declined steadily and is at its lowest level in recorded history — about 1,200 seals. Unless the current trajectory of population numbers is reversed, the species' abundance is expected to fall below 1000 in the next four years. Currently, a monk seal pup's chance of surviving to the reproductive age of seven to ten years is less than one in five.
Monk seal scientists at the Pacific Islands Fisheries Science center and several partner agencies and organizations are trying to improve pup survival, and thereby increase the population growth rate, through captive care and release. This approach has shown success for monk seals and other seal species as well. A captive care pilot project was recently completed at Midway Atoll, in the Papahānaumokuākea Marine National Monument. The Midway project was designed to carefully identify and evaluate care and husbandry issues that need to be resolved to enable launch of a much larger captive care effort.
We are now analyzing data we collected during the Midway Atoll project to assess what was learned in the pilot study and how captive care can be applied to increase the survival and recovery of Hawaiian monk seals. During the project we successfully collected 6 weaned monk seal pups and placed them in shoreline pens at Midway. After providing them with nutritional support over the winter of 2006-2007, we released them into the wild in much improved condition. Additional details of the project are provided below.
The captive care and release initiative is part of a broader strategy of PIFSC monk seal scientific research and recovery. One aspect of the research is satellite tracking of the seals after their release to learn about their movements and behavior.
The Midway Captive Care Project
![hawaiian monk seal](img/feed_monk.jpg)
The purpose of the Midway captive care pilot study was to enhance recovery of the endangered Hawaiian monk seal population by improving early survival of seals, especially females. In October 2006 twin female pups born at Midway Atoll and rehabilitated at the PIFSC Kewalo Research Facility in Honolulu were returned to Midway and placed in a protective pen for further care. Other pups were added later to the Midway care group. All the captive pups were released into the wild in March - April 2007. While under captive care, the seals were housed in protective pens straddling the beach and adjacent shallow water and fed fish to fatten them up in preparation for the challenges they would face learning to feed on their own after release. Keeping the vulnerable pups in captive care ensured their nourishment and also protected them from harm or death due to sharks, aggressive male seals, and entanglement in derelict fishing gear and other marine debris in the nearshore reef habitat.
The pilot Captive Care project just completed was established as a collaboration between the NOAA Pacific Islands Fisheries Science Center and Pacific Islands Regional Office, the Marine Mammal Center, the U.S. Fish and Wildlife Service - Midway Atoll National Wildlife Refuge, Hubbs-Sea World Research Institute, and Sea World. Other partners are the U.S. Coast Guard and NOAA Weather Service. The plan of action includes several steps:
- Collecting female pups at weaning and supporting them in the shoreline pens.
- Continuously observing free roaming seals at Midway while maintaining seals under captive care to better understand the potential causes of pup mortality.
- Using satellite linked telemetry to record geographic location and diving behavior, and to track free roaming male pups (as control animals) and the released female pups, comparing their movements and activities. This phase of the research began in April 2007.
Our partners in the captive care project contributed materially to its success. We thank them and look forward to collaborating with them in the future.
To learn more about why captive care studies and other research are critical to monk seal conservation, take a look at the recently adopted Recovery Plan for the Hawaiian Monk Seal (pdf). Also refer to the Report of the Hawaiian Monk Seal Captive Care Workshop (pdf) held in Honolulu June 11-13, 2007.
Profiles of Captive Care Pups
These female pups were released from captive care into the wild at Midway Atoll. Satellite tracking was used to monitor their post-release movements during the pilot study.
The pups identified as PO22 and PO26 are fraternal twins born on April 9, 2006 on Spit Island, Midway Atoll. Twinning in monk seals is a rare event—this was only the fourth pair known. Underweight at weaning, the twins were rehabilitated at the PIFSC Kewalo Research Facility in Honolulu before being put under captive care at Midway.
![PO22](img/po22.jpg)
- ID: PO22
- Date of Birth: April 9, 2006
- Place of Birth: Spit Island, Midway Atoll
- Admit Date: May 27, 2006
- Admit Weight: 65.5 lbs
- Release Date: March 19, 2007
- Release Weight: 159.0 lbs
- Weight Change: 93.5 lbs
- % Body Wt Change 142.7
![PO26](img/po26.jpg)
- ID: PO26
- Date of Birth: April 9, 2006
- Place of Birth: Spit Island, Midway Atoll
- Admit Date: May 27, 2006
- Admit Weight: 79.5 lbs
- Release Date: March 19, 2007
- Release Weight: 193.0 lbs
- Weight Change: 113.5 lbs
- % Body Wt Change 142.8
![PO40](img/po40.jpg)
- ID: PO40
- Date of Birth: May 20, 2006
- Place of Birth: Eastern Island, Midway Atoll
- Admit Date: October 23, 2006
- Admit Weight: 86.5 lbs
- Release Date: March 22, 2007
- Release Weight: 132.5 lbs
- Weight Change: 46.0 lbs
- % Body Wt Change 53.2
![PO42](img/po42.jpg)
- ID: PO42
- Date of Birth: June 6, 2006
- Place of Birth: Eastern Island, Midway Atoll
- Admit Date: December 24, 2006
- Admit Weight: 94.0 lbs
- Release Date: March 22, 2007
- Release Weight: 123.0 lbs
- Weight Change: 29.0 lbs
- % Body Wt Change 30.9
![PO46](img/po46.jpg)
- ID: PO46
- Date of Birth: June 8, 2006
- Place of Birth: Spit Island, Midway Atoll
- Admit Date: November 01, 2006
- Admit Weight: 124.5 lbs
- Release Date: March 19, 2007
- Release Weight: 170.0 lbs
- Weight Change: 45.5 lbs
- % Body Wt Change 36.5
![PO48](img/po48.jpg)
- ID: PO48
- Date of Birth: July 12, 2006
- Place of Birth: Sand Island, Midway Atoll
- Admit Date: October 31, 2006
- Admit Weight: 96.5 lbs
- Release Date: March 22, 2007
- Release Weight: 140.0 lbs
- Weight Change: 43.5 lbs
- % Body Wt Change 45.1
Project Partners
- NOAA Pacific Islands Fisheries Science Center
- NOAA Pacific Islands Regional Office
- NOAA Weather Service
- Marine Mammal Center
- SeaWorld San Antonio
- Hubbs-SeaWorld Research Institute
- US Fish and Wildlife Service
- US Coast Guard
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