Mixed News for the Hawaiian Monk Seal

Telemetry equipment is providing valuable information about the habitat needs of the Hawaiian monk seal.

Photo Credit: Justin Viezbicke

by T. David Schofield

Question: What is the most critically endangered marine mammal whose entire range lies within the United States?

Answer: The Hawaiian monk seal (Monachus schauinslandi).

Photo Credit: NOAA

This "living fossil" is documented in the scientific literature as the most ancient of all pinniped (fin-footed animal) species. Originating 14 to 15 million years ago, this species is older than some of the Hawaiian Islands it now inhabits. The bad news is that only about 1,100 Hawaiian monk seals remain. Ninety percent of them live in the Refuge and Monument systems of the Northwestern Hawaiian Islands (NWHI) in the Midway Atoll and Hawaiian Islands National Wildlife Refuges, which are managed by the U.S. Fish and Wildlife Service, and at the very tip of the state’s Kure Atoll Seabird Sanctuary. The NWHI population is declining by 4 percent per year. The somewhat good news is that the remaining 10 percent—estimated at 100 individuals found throughout the eight main Hawaiian Islands—are increasing.

Problems such as poor female juvenile survival, entanglement in fishing gear and other marine debris, shark predation, diminishing beach habitat due to sea level rise, and reduced prey availability (which is due to people fishing and other top predator animals) are recognized as causes for the recent decline in the NWHI. Historical causes included pressure from military use of the islands and an intensive sealing and exploration expedition in the mid-1850s. However, the seal population in the main Hawaiian Islands appears to be on the rebound. Although the carrying capacity for monk seals in the main islands is unknown, 88 individuals are routinely sighted, a number that is based on such mark-recapture methods as identifying markings, flipper tags, and tracking by telemetry equipment.

Abundance trend at 6 NWHI subpopulations (source: Jason Baker, NOAA/NMFS/PIFSC).

The Recovery Plan for the Hawaiian Monk Seal established a range-wide population goal of maintaining 2,900 individuals for 20 years before the seal can be removed from Endangered Species Act protection. Projections suggest that the main Hawaiian Islands would have to sustain 500 of the seals. Currently, seals there appear to be thriving; the adults appear to be larger than those in the NWHI, mothers appear to be very healthy prior to giving birth, births are increasing, and pups are larger and healthier in comparison to the NWHI pups.

Photo Credit: NOAA

While the monk seal population growth in the main islands is encouraging, these animals face complex and unique impacts that were not previously observed in the larger NWHI population. Non-fatal hookings during recreational fishing, fatal entanglements, dog attacks, and conditioning to humans are among the threats that may be disastrous for the population in the main islands. For example, "R042," a female monk seal born on a popular beach on the Big Island of Hawai‘i, quickly became desensitized to humans. As a result, she began to exhibit friendly behaviors and interactions with people that led to swimming together, tactile petting, and feeding. This seal was first adopted by the local community, but she was soon admonished after becoming too playful and occasionally aggressive. After she jumped onto kayaks and surfboards, it was clear that these behaviors could become a nuisance to people, and the seal had to be relocated to another island. This is the third monk seal that required removal from its island of origin due to negative interactive behavior. In 2003, another monk seal from the Big Island was moved to the island of Kaho‘olawe and eventually moved farther away to Johnston Atoll. A second seal was removed from Kaua‘i and sent to Ni‘ihau. Moving seals away from their island of origin is not a preferred management practice. It demonstrates the need for increased public education about the problems caused by conditioning monk seals to interact with people.

With the decline of the NWHI population, the future of the Hawaiian monk seal may depend on the survival of the increasing population in the main islands. The National Marine Fisheries Service (NMFS) Pacific Islands Regional Office has developed a network of dedicated community members to foster public involvement in monk seal conservation. During the past three years, several island coordinators and a large cadre of volunteers throughout the state have enlisted in the effort. The volunteer network includes approximately 300 members from diverse backgrounds. On a daily basis, they respond to reports of seal haul-outs (literally, seals hauling themselves onto the beach), educate local citizens and tourists, record information, and provide the NMFS Pacific Islands Fisheries Science Center with images that are used to identify and monitor the seals. Outreach programs include a statewide Hawaiian Monk Seal Count every April and October, and school programs have been developed by volunteer teachers. These tools have proven useful in fostering the concept that recovering the monk seal will require efforts by all of us.

Births of Hawaiian monk seals in the main Hawaiian Islands are increasing (source: Tracy Wurth NOAA/NMFS/PIFSC).

Learning from the growing public awareness of the humpback whale following its designation as the official Hawaii State Marine Mammal, monk seal response volunteers lobbied to appoint the seal as the official Hawaii State Mammal. This process helped to inform the Hawaii State Legislature on the critical status of the monk seal while elevating public awareness.

It is imperative that the public understand the plight of the Hawaiian monk seal and support efforts to prevent its continued decline. This year, one of the world’s three species of monk seal was declared extinct (see the following article on the Caribbean monk seal). We all need to work to avoid such a fate for the Hawaiian monk seal—a unique natural treasure.

T. David Schofield, Interim Hawaiian Monk Seal Recovery Coordinator and Marine Mammal Response Network Coordinator in the NMFS Honolulu, Hawaii, office, can be reached at David.Schofield@noaa.gov or 808-944-2269.