Rehabilitation and Relocation of Young Hawaiian Monk Seals
August 29, 2011
A study of the 1984-1995 program that collected 104 monk seals whose mortality appeared certain; and attempted to nourish and rehabilitate these animals to enable their release.
Observed high pup and juvenile mortality, as a result of starvation conditions that were prevalent in the Hawaiian monk seal (Monachus schauinslandi) population in the Northwestern Hawaiian Islands (NWHI), led to the development of a rehabilitation and reintroduction program for underweight monk seals.
During 1984-1995, the program collected 98 young female monk seals whose mortality appeared certain (underweight and in some cases ill) from French Frigate Shoals (FFS) and attempted to nourish and rehabilitate these animals to enable their release as healthy individuals.
Six additional young females of normal size were relocated from FFS (5) and Oahu (1) to Kure Atoll where their survival rate was expected to be higher than at their birth islands.
The goal of the program was salvaging the reproductive potential of young female monk seals to aid in the recovery of this endangered species.
Of the 104 animals collected, 17 died in captivity, 13 were converted to permanent captivity (for health or behavioral reasons), and the remaining 74 were released at Kure Atoll or Midway Islands within 14 mo of collection. Survival during the first year post-release was compromised, compared to native seals (born at the release site) but was similar to survival of natives in the second year.
The released monk seals migrated among the three westernmost atolls at a higher rate than native seals. Monk seal monitoring continued through 2005 when 32 animals were known to be alive; they, with their offspring, constituted at least 12 to 14% of the animals in the three western NWHI populations. Captive-care management strategies were developed in a rapid response and varied greatly as did the success.
These results are critical to the development of future captive-care initiatives that may be necessary to mitigate the continuing high loss of young monk seals in the NWHI.
Gilmartin W, Sloan AC, Harting AL, Johanos TC, Baker JD, Breese M, Ragen TJ. 2011. Rehabilitation and relocation of young Hawaiian monk seals (Monachus schauinslandi) Aquatic Mammals 37(3): 332-341. DOI:10.1578/am.37.3.2011.332