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Hawaiian Monk Seal (Monachus schauinslandi)

Status | Taxonomy | Species Description | Habitat | Distribution |
Population Trends | Threats | Conservation Efforts | Regulatory Overview |
Key Documents | More Info

  Hawaiian Monk Seal on beach
Hawaiian Monk Seal
(Monachus schauinslandi)
Photo: NOAA


satellite tracking map
Hawaiian Monk Seal satellite tracking
(Monachus schauinslandi)
Credit: NMFS Pacific Islands
Fisheries Science Center


 

 

 Hawaiian Monk Seal
Hawaiian Monk Seal
(Monachus schauinslandi)
Photo: NMFS Pacific Islands
Fisheries Science Center


Hawaiian monk seal, mom and pup
Hawaiian Monk Seal mom and pup
(Monachus schauinslandi)
Photo: NOAA


Status
ESA Endangered - throughout its range
MMPA Depleted - throughout its range
CITES Appendix I - throughout its range

Taxonomy
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Phocidae
Genus: Monachus
Species: schauinslandi

Species Description
Weight: 375 lbs-450 lbs (170-205 kg), females are slightly larger than males;
pups weigh about 35 lbs (16 kg) at birth
Length: 7.0-7.5 feet (2.1-2.3 m), females are slightly larger than males;
pups are about 3 feet (1 m) at birth
Appearance:  silvery-grey backs with lighter creamy coloration on their underside; newborns are black. They may also have light patches or red and green tinged coloration from attached algae.
Lifespan: 25-30 years
Diet: fish, cephalopods, and crustaceans
Behavior: monk seals breed and haul-out on sand, corals, and volcanic rock; they are often seen resting on beaches during the day

The Hawaiian monk seal is one of the rarest marine mammals in the world. Part of the "true seal" family (Phocidae), they are one of only two remaining monk seal species. The other is the Mediterranean monk seal. A third monk seal species--the Caribbean monk seal--is extinct.

Isolated from their closest relative 15 million years ago, Hawaiian monk seals are considered a "living fossil" because of their distinct evolutionary lineage.

Females generally mature around age 5; it is unknown when males mature. Monk seals are promiscuous and mate underwater. Given male-dominated sex ratios at some breeding colonies, group mobbing of "estrus" females is known to occur, sometimes causing serious injury or even death to the female.

The gestation period is 10-11 months. Birthing rates vary with a range of 30-70% of adult females birthing in a given year. While most births occur in late March and early April, birthing has been recorded year round. Newborns are black, and then molt near the end of their nursing period.

Nursing occurs for about 1 month, during which time the mother fasts and remains on land. After this period, the mother abandons her pup and returns to sea. Although they are generally solitary animals, females have been observed fostering others' offspring.

Monk seals are primarily "benthic" foragers, feeding on a variety of prey including fish, cephalopods, and crustaceans. Their diet varies by location, sex, and age. Adults are generally nocturnal hunters while juveniles spend more time hunting species that hide in the sand or under rocks during the day. Monk seals generally hunt for food outside of the immediate shoreline areas in waters 60-300 feet (18-90 m) deep. Monk seals are also known to forage deeper than 1,000 feet (330 m), where they prey on eels and other benthic organisms.

Tiger sharks and Galapagos sharks prey on monk seals.

  Hawaiian Monk Seal on beach
Hawaiian Monk Seal
(Monachus schauinslandi)
Photo: NOAA

hawaiian monk seal critical habitat
Hawaiian Monk Seal
Critical Habitat

(click for larger view PDF)
» Proposed Revision to Critical Habitat

Habitat
Monk seals live in warm subtropical waters and spend two-thirds of their time at sea. They use waters surrounding atolls, islands, and areas farther offshore on reefs and submerged banks. Monk seals are also found using deepwater coral beds as foraging habitat. When on land, monk seals breed and haul-out on sand, corals, and volcanic rock. Sandy, protected beaches surrounded by shallow waters are preferred when pupping. Monk seals are often seen resting on beaches during the day.

Critical Habitat
Critical habitat has been designated under the ESA to include all beach areas, sand spits and islets, including all beach vegetation to its deepest extent inland, and lagoon waters out to a depth of 20 fathoms (120 ft) in designated areas of use.

In June 2012, NOAA announced a 6-month extension of the deadline for a final determination on the proposed rule, based on comments received during the public comment period. In June 2011, NMFS proposed to revise critical habitat [pdf]. In June 2009, NOAA Fisheries announced its intention to revise [pdf] the Hawaiian monk seal's critical habitat. More information on Hawaiian monk seal critical habitat is available on the NMFS Pacific Isalnds Regional Office website.

 
Hawaiian monk seal range map
Hawaiian Monk Seal Range Map
(click for larger view PDF)

Distribution
The Hawaiian monk seal's entire range is within U.S. waters. The majority of monk seals live in six main breeding subpopulations in the Northwestern Hawaiian Islands (NWHI) at:

  • Kure Atoll
  • Midway Islands
  • Pearl and Hermes Reef
  • Lisianski Island
  • Laysan Island
  • French Frigate Shoals

Smaller breeding sub-populations also occur on Necker Island and Nihoa Island. Monk seals have been observed at Gardner Pinnacles and Maro Reef.

Most of the population is within the Papahānaumokuākea Marine National Monument, which was designated in 2006.

Monk seals are now also found on the Main Hawaiian Islands (MHI), where births have occurred on many of the major islands.

Population Trends
The monk seal population is currently declining at about 4% annually and is estimated at around 1,200 individuals. Hunted to the brink of extinction in the late 19th century, Hawaiian monk seals have been declining since modern surveying began. Biologists predict this number will dip below 1,000 in the next few years, placing this species among the world's most endangered. While the larger NWHI population is shrinking, the MHI population is growing, with a population estimated at around 150 animals.

 

entangled hawaiian monk seal
Hawaiian Monk Seal, entangled
(Monachus schauinslandi)
Photo: NOAA



Threats

  • Food limitations in NWHI, especially for juveniles and sub-adults
  • Entanglement in marine debris
  • Human interactions (especially in the MHI) including
    • bycatch in fishing gear
    • mother-pup disturbance on beaches
    • exposure to disease
  • Loss of haul-out and pupping beaches due to erosion in NWHI
  • Disease outbreaks
  • Male aggression towards females
  • Low genetic diversity
 

Hawaiian Monk Seal Recovery Plan Signing Ceremony
Recovery Plan Signing
Photo: NOAA



Conservation Efforts
NOAA Fisheries and partners are implementing the Recovery Plan [pdf] for the hawaiian monk seal.

Research investigating resource availability, foraging behavior (including use of crittercam This link is an external site.), reproduction, and disease will help scientists and resource managers make better decisions.

Public education campaigns, including projects to reduce monk seal-human interactions on the MHI, are building awareness about conserving the species and habitat.

Volunteer groups are being expanded to help rescue and rehabilitate animals and prevent undue stress by keeping beachgoers away from resting animals. Direct efforts to disentangle seals and remove debris from haul-out sites have led to the removal of 492 metric tons (over 1 million pounds) of marine debris in NWHI since 1996, reducing injuries and death due to entanglement and digestion of marine debris.

The Hawaiian monk seal is listed as "endangered" in the IUCN Red List of Threatened Species This link is an external site..

NMFS has developed a video, "Good Neighbors: How to Share Hawaii's Beaches with Endangered Hawaiian Monk Seals," to enhance understanding of human-seal interactions and the direct impact that has on the population and recovery of the monk seal species:

link to Good Neighbors video
Video: How to Share Hawaii's Beaches with Endangered Monk Seals
Credit: NMFS Pacific Islands Regional Office

 
Hawaiian Monk Seal in the water
Hawaiian Monk Seal
(Monachus schauinslandi)
Photo: NMFS Pacific Islands
Fisheries Science Center

Hawaiian Monk Seal
Hawaiian Monk Seal
(Monachus schauinslandi)
Photo: NMFS Pacific Islands
Fisheries Science Center

Regulatory Overview
In 1976, the Hawaiian monk seal was listed as endangered under the Endangered Species Act.

Under the MMPA, Hawaiian monk seals are classified as "strategic stocks" and are considered "depleted".

NMFS designated critical habitat [pdf] in May 1988 (53 FR 18988) that includes all beach areas, sand spits and islets, including all beach vegetation to its deepest extent inland, and lagoon waters out to a depth of 20 fathoms (120 ft) for the following areas:

  • Kure Atoll
  • Midway Islands, except Sand Island and its harbor
  • Pearl and Hermes Reef
  • Lisianski Island
  • Laysan Island
  • Maro Reef
  • Gardner Pinnacles
  • French Frigate Shoals
  • Necker Island
  • Nihoa Island

In June 2012, NOAA announced a 6-month extension of the deadline for a final determination on the proposed rule, based on comments received during the public comment period. test In June 2011, NMFS proposed to revise critical habitat [pdf]. In June 2009, NOAA Fisheries announced our intention to revise the Hawaiian monk seal's critical habitat.

Hawaiian monk seals are also listed on Appendix I of the Convention on International Trade in Endangered Species (CITES).

Key Documents
(All documents are in PDF format.)

Title Federal Register Date
Revised taxonomy and nomenclature for Hawaiian monk seals, effective 01/16/2015 79 FR 68371 11/17/2014
Programmatic Environmental Impact Statement (PEIS) for Recovery Actions 79 FR 20172 04/11/2014
NMFS proposes to revise critical habitat for Hawaiian monk seals
  • 6-Month Extension of Deadline for Final Critical Habitat Determination
76 FR 32026


77 FR 37867
06/02/2011


06/25/2012
NMFS "12-month finding" to Revise Critical Habitat 74 FR 27988 06/12/2009
Possible Revisions to Critical Habitat Designation 73 FR 57583 10/03/2008
Recovery Plan (2007) 72 FR 46966 08/22/2007
n/a 03/24/1983
Response to Comments on 2007 Recovery Plan 72 FR 46966 08/22/2007
5-Year Review 72 FR 46966 08/22/2007
Critical Habitat Designation (1988 Revised) 53 FR 18988 05/26/1988
51 FR 16047 04/30/1986
ESA Listing Rule 41 FR 51611 11/23/1976
Stock Assessment Reports n/a various

More Information

Updated: November 19, 2014

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