About the Hawaiian Monk Seal

Oahu 19-year-old Female Rocky (RH58)

The Hawaiian monk seal, Neomanachus schauinslandi, is one of the most endangered marine mammals in the world

Most seals are at home in frigid waters, but the Hawaiian monk seal is a rare tropical exception. The Hawaiian name for the monk seal is Ilio-holo-i-ka-uaua, meaning dog running in the rough seas.  They are well respected by the people of Hawaii and many locals consider them one of Hawaii’s most unique and valuable marine-life treasures.  The females are particularly coveted as they are the cornerstone of the recovery of the Hawaiian Monk Seal species.

The Hawaiian Monk Seal lives in the waters of the Hawaiian archipelago which includes both the main and Northwestern Hawaiian Islands (NWHI).  Current population estimates are 1,400 total seals with approximately 300 living throughout the main Hawaiian Islands and the remaining in the NWHI chain.

The average monk seal in the wild can live about 25 years; those in captivity can live longer due to better living conditions, medical treatment, diets and no predation challenges. Hawaiian monk seal females are quite a bit larger than the males. Females average about 600 pounds with the males weighing in on average between 400-500 pounds. Females are about 8 feet long and males slightly shorter around 7 feet.

Oahu 3-year-old Juvenile Female Kawena (RH36)

Hawaiian monk seals “haul out” on land sometimes for long resting periods but the average seal spends about 1/3 of its time on land.  The other 2/3 is spent in the water where they can forage and swim at great depths of more than 1,800 feet but they are usually found closer to the surface in depths of about 300 feet or less.  They can stay underwater for about 20 minutes, however, their normal dive time is about 6-10 minutes.

Hawaiian monk seals are mostly solitary marine animals and don’t live in colonies like other similar species. They can be seen lying near each other, even sometimes in small groups, but usually not close enough to make physical contact. They normally can be seen hauling out on Hawaii’s beaches or rocks and staying there, sometimes for days at a time. They also have been seen sleeping in small underwater caves.

Because the monk seal spends so much of its time in the water, it’s fur can get a build up of green algae that can eventually turn a brownish color. Around the same time each year (pregnant females usually after weaning their pups) monk seals will shed their algae-ridden fur during a brief 1-2 week natural process called a “catastrophic molt”.

Kauai 6-year-old Male N02 Molting

Hawaiian monk seals are generalist foragers which means they eat a wide variety of foods depending on what’s available. They eat many types of common fishes, squids, octopuses, eels, and crustaceans (crabs, shrimps, and lobsters). Diet studies indicate that they forage at or near the seafloor and prefer prey that hide in the sand or under rocks. It is noteworthy that they don’t compete with Hawaii’s fishermen since they do not target most of the more popular local gamefish species such as ulua (giant trevally), pāpio (baby ulua), and ‘ō‘io (bonefish).

Threats to monk seals include food limitation, shark predation, net entanglement, male seal aggression, habitat loss, fishery interactions, disease, human interactions, and intentional killings.

STATUS:  Endangered!

What does that mean? It is estimated that there are more than 30 million animal and plant species on our planet.  An “endangered” species is a species which has been categorized as “very likely to become extinct in the near future”.  When a species is measured to be on the brink of extinction mainly due to one or more causes such as man’s intervention for consumption or entertainment it is classified in one of 9 different categories by the International Union for Conservation of Nature (IUCN) Red List.  Endangered (EN) is the second most severe conservation status for wild populations in the IUCN’s schema after Critically Endangered (CR).


Federal and state governments and their law enforcement divisions are responsible for protecting those species who have been categorized as being endangered, threatened, etc.  However, before a species can receive the protection provided by the Endangered Species Act (ESA), it must first be added to the federal lists of endangered and threatened wildlife and plants. The List of Endangered and Threatened Wildlife (50 CFR 17.11) and the List of Endangered and Threatened Plants (50 CFR 17.12) contain the names of all species that have been determined by the U.S. Fish and Wildlife Service (Service) or the National Marine Fisheries Service (for most marine life) to be in the greatest need of federal protection.

In 2010, because of a human’s intentional and brutal attack of a Hawaiian Monk Seal on the Island of Kauai, which resulted in both the death of a pregnant female and her unborn pup, volunteers rallied to instate stricter laws to protect the Hawaiian Monk Seals. Then, Hawaii Lt. Gov. James “Duke” Aiona signed Senate Bill 2441 into law, making the intentional harassing, harming or killing of a monk seal—or any endangered or threatened Hawaii species—a class C felony. The Hawaii law extends punishment already imposed by violations of the federal Endangered Species Act, to include a fine of up to $50,000 and five years in prison.

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Oahu 14-year-old Male Buster (RV08)

“Coexistence”:  Viewing Monk Seals Responsibly

Recreation near or in the ocean is what Hawaii is all about.  It’s one of the main reasons  visitors flock to Hawaii all year long and residents love where they live.  In 2018, Oahu alone hosted an estimated 6 million tourists.  More than likely at some point during their stay they ventured out to spend time taking in paradise either on the beach or in the ocean.   With that many visitors it’s highly likely that humans and monk seals came into contact with each other.   To promote coexistence and provide protection for the monk seal and safety for Oahu’s visitors and residents, NOAA suggests the following responsible viewing guidelines:

  • DO give them their space; view them from a distance both on land AND in the water!  To live a long and healthy life, monk seals need rest to forage for food and ward off predators.  Use binoculars or your camera’s zoom for a close up.
  • DO respect any roped off areas or signage that indicate the presence of a monk seal. Do not cross the line!
  • DO limit your viewing time to a few minutes.
  • DO follow the “rule of thumb” to calculate a safe distance when observing resting monk seals.  To figure out how much space to give them, simply make a “thumbs-up” gesture and extend your arm out straight in front of you, with your thumb parallel to the ground. If your thumb covers the entire seal, you are far enough away. NOAA’s recommended safe viewing distance is 50 feet or 150 feet for pupping locations. View from a distance. Use binoculars or your camera’s zoom for a close up.
  • DON’T ever touch, chase, or feed a monk seal. Animals are wild, unpredictable and protected.
  • DON’T push them back into the water – they’re resting!
  • DON’T interact with the monk seals…move away from them slowly and please, no seal selfies!  If you’re in the ocean, cautiously exit the water.
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Oahu 18-month-old Juvenile Male Kuokala (RK88) drowned in a lay gil net August 2019

Monk Seal-Friendly Fishing Tips

Two of 9 major threats to Hawaiian Monk Seals are fishing related – entanglement and fishery interactions.  Serious and sometimes fatal injuries occur when monk seals are caught in nets or accidentally hooked.

Entanglement – Hawaiian monk seals have one of the highest documented entanglement rates of any pinniped species, and pups and juveniles are the most often entangled. Just this year, Oahu lost a juvenile monk seal on the North Shore when it got caught in a fishing net that was left unattended for an extended length of time.  Because Hawaiian Monk Seals can only stay under water for up to 20 minutes, juveniles even less time, once caught in a net they have very little time to find their way out.  Marine debris and derelict fishing gear are chronic forms of pollution affecting monk seal habitat and sometimes even being ingested by seals which can cause serious and even fatal complications.

Fishery InteractionsBetween 1976 and 2016*, there were 155 documented hookings and entanglements in gill nets, which resulted in 12 monk seal deaths. Expert fishermen, together with state and federal wildlife managers, have developed best practice guidance for fishermen who may interact with monk seals: spearfishing, shorecasting, and gillnet fishing.

Just by implementing these seal-friendly tips, fishermen and monk seals can co-exist with less occurrences of harm or death to the species:

  • Use barbless circle hooks.
  • Reuse or share leftover bait, don’t feed the seals
  • Reel in your line if monk seals get near
  • Change locations if seals show interest in your bait or catch
  • If net fishing, do not leave a net unattended for more than a half hour
  • Visually check nets every 2 hours or more frequently if possible
*most up-to-date NOAA statistics on line
Oahu 11-year-old Adult Male PV Kauai (RW04)


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