Hawaiian Monk Seal
Federally-Listed - Endangered
State-Listed - Endangered
State Recognized - Indigenous and Endemic
IUNC Red List – Critically Endangered
Monk seals are divided into 2 genera (Monachus, which was the original genus for all monk seals, and Neomonachus); the Mediterranean monk seal is still in the original genus Monachus, whereas the Hawaiian and Caribbean monk seal have been placed in the new genus Neomonachus. Because the Caribbean monk seal is extinct, this recent reclassification means that the endangered Hawaiian monk seal is the only surviving member of the Neomonachus genus and is also the only endangered marine mammal that occurs exclusively within the United States.
Īlio-holo-i-ka-uaua, or Hawaiian monk seals, are benthic feeders and rely on a general foraging tactic aimed at food hiding in the rocks or under it. This would include reef fishes, octopus, squid, and lobsters over many substrates up to depths of 305 meters (1,000 feet). Juveniles feed on a higher proportion of nocturnal fish species.
Distribution & Abundance
In a 2018 report, data collected in 2016 shows that the total population of Hawaiian monk seal is about 1415 across the entire Hawaiian archipelago. 80% of the total population, about 1132 monk seals, are living in the Northwestern Hawaiian Islands. The total monk seal subpopulation on Kure is about 98 seals with just about 78 adults and 20 pups. The number of monk seal pups born from year to year varies from 11 to 21.
Location & Condition of Key Habitat
They are usually solitary, except on preferred beaches where they rest and interact with each other. Mating generally occurs in the spring and summer. The period of gestation is unknown, however, the interval between consecutive births is a little over one year. Pupping can occur in all months of the year with the majority occurring in late winter and spring/summer months. Weaning lasts five to six weeks and pups and mothers stay ashore or in nearshore waters until pups are weaned. Foster parenting occurs. Sexual maturity occurs at around five to ten years of age. The oldest know monk seals have lived for over 30 years, but few reach that age.
Monk seals rest periods provide the time to regain energy in between foraging. They can sometimes be found resting on beaches or in high vegetation along the shoreline for days at a time. They can also be found resting underwater in small caves, and sometimes on exposed reef flats in between dives.
From the early 19th century, sealing expeditions aggressively harvested Hawaiian monk seals for commercial use to the brink of extinction. By the turn of the 20th century, and in response to these industry-wide overharvesting practices of many different marine species, the first layers of environmental protections were established to give Northwestern Hawaiian Island (NWHI)I the space to recover. The monk seal population increased following exploitation and by 1958, when the first beach count of all major NWHI was conducted, the population was about three times what it is today. The population declined thereafter and in 1976, it was designated “Depleted” under the Marine Mammal Protection Act of 1972 and as “Endangered” under the Endangered Species Act of 1973.
From the late 1970s, and over the next 40 years, the population has continued to decline and is one of the highest priority species in Hawaiʻi conservation today. The species relies heavily on conservation and species-specific wildlife management to provide the interventions necessary to ensure its survival.