Sealing the Deal

 Hawaiian Monk Seal

  Jenna Dockray 

Adult Hawaiian monk seal basking in the sun. Image from marine conservation. 

Description and Ecology of the Hawaiian Monk Seal

The Hawaiian monk seal, Monachus schauinslandi, is one of the most rare marine mammals, as well as the second most endangered seal species in the world. These endemic species to the Hawaiian Islands spend most of their time at sea, but come ashore to rest or breed on uninhabited, isolated beaches. 

The lifespan of these tropical mammals range from 25-30 years old. Full-size adult monk seals have an average weight of  375-450 pounds and length of 7-7.5 feet long, although females are typically larger than males. The Hawaiian monk seal has a grey, silver, or brown coat with a lighter underbelly. However, newborns have a black body, weighting around 35 pounds and measuring three-feet in length. 

Pup monk seal cuddles with mother.
Image from NOAA.

Newborns are bred between February to July on protected beaches in shallow water. After birth, the female ventures out for food, forcing the pup to survive on its own. Once the newborns enter the marine habitat, they will spend almost two-thirds of their life in the ocean searching for prey. Hawaiian monk seals are "benthic foragers" and will feed off bottom-dwelling organisms at any depth. Their diets consist of fish, cephalopods, and crustaceans. (NOAA)

Geographic and Population Changes

This pinniped species inhabits the Northwestern Hawaiian Islands. The majority of monk seals live in six main breeding subpopulations; Kure Atoll, Midway Islands, Pearl and Hermes Reef, Lisianski Island, Laysan Island, and the French Frigate Shoals. It is crucial to protect these subpopulations because the Hawaiian monk seal is one of the last monk seal populations. 

The Hawaiian monk seal is found on the beaches and in the waters 

of the northwestern Hawaiian islands, or Leeward Chain.Image from the Recovery Plan.   

They are also critical because Hawaiian monk seals do not migrate, and are extremely localized and endemic. Their population ranges from 1,200 to 1,400 individuals. Since 1965, the Monachus schauinslandi population has decreased by 60%, an alarming record low.

This graph shows the negative correlation between time and population abundance since 1998.
Image from National Marine Fisheries Service National Oceanic and Atmospheric Administration.

Listing Date and Type of Listing

On November 23, 1976, the Hawaiian monk seal was officially listed under the Endangered Species Act as an endangered species with a priority number of one, for immense and extensive threats. Since then, two pervious recovery plans have been implemented to research and recover the Hawaiian monk seal. Although the recovery plans did not result in an increase in population, new scientific research has helped study and manage the seals while preventing a loss in genetic diversity amongst the subpopulations. The current Recovery Plan was put into action on August 22,2007. 

The recovery plan protects beaches for Hawaiian Monk Seals. Image from Conservation Hawaii. 

Cause of Listing and Main Threats to Continued Existence

Dead Hawaiian monk seal drifted ashore. Image from NOAA.

The Hawaiian monk seal is a highly endemic, localized species and therefore is constantly threatened by outside disturbances. Natural factors threatening the Hawaiian monk seal include low juvenile rates, male aggression, disease, increase in predators, food limitation, environmental erosion, and climate changes. Anthropogenic factors encompass all human disturbance, marine debris, destruction of habitat, and overexploitation. 

The Recovery Plan

The recovery plan for the Hawaiian monk seal includes four steps in order to assure long-term viability and the removal from the Endangered Species List. 

1. Improve the survival rate of juvenile and adult females by protecting habitats, intervening shark predators, reducing exposure to male aggression, and avoiding entanglement. 
2. Monitoring and maintaining an observatory and active role in the breeding process for Hawaiian monk seals. 
3. Increased collaboration and support from federal, state, and local governments, nonprofits, and volunteers to educate tourists and local citizens. Through funding and awareness, there will be a decline in human disturbances, exposure to diseases, and fatal entanglements for Hawaiian monk seals. 
4. All action to prevent invasive and infectious diseases, toxins, and parasites.   

Once there is a total population over 2,900, subpopulations with over 100 individuals, and a reproductive rate exceeding mortality rate, then Hawaiian monk seals will be considered "threatened" and no longer endangered. 

Click Picture for a video on Monk Seals!! Image from Wikimedia.