Hawaiian monk seals and toxoplasmosis—infographic and frequently asked questions.
Hawaiian Monk Seal
About The Species
The Hawaiian monk seal is one of the most endangered seal species in the world. The population overall has been declining for over six decades and current numbers are only about one-third of historic population levels. Importantly, however, the prolonged decline has slowed over the last 10 years, thanks in many ways to recovery efforts.
Hawaiian monk seals are found in the Hawaiian archipelago which includes both the main and Northwestern Hawaiian Islands and rarely at Johnston Atoll which lies nearly 1,000 miles southwest of Hawai'i. These monk seals are endemic to these islands, occurring no where else in the world. Hawaiian monk seals are protected under the Endangered Species Act, the Marine Mammal Protection Act, and State of Hawai'i law.
The Hawaiian monk seal is one of NOAA Fisheries' Species in the Spotlight.
Rocky, the Famous Hawaiian Monk Seal
Rocky became famous in 2017 when she had a pup on a busy beach in Waikiki. She returned to Kauai on July 14, 2018, and on July 16, 2018, she was observed with a new pup.
The population is estimated to be around 1,400 seals—about 1,100 seals in the Northwestern Hawaiian Islands and 300 seals in the main Hawaiian Islands.
A prolonged decline of the Hawaiian monk seal population in the NWHI occurred after the late 1950s, lasting until very recently. While individual subpopulations increased or decreased during that time, the total number of seals in the NWHI declined. Although this decline means that a full recovery of the species is a long way off, there have been some relatively recent, encouraging developments, including:
- Apparent recolonization and significant growth of the main Hawaiian Islands monk seal subpopulation from low numbers to approximately 300 over the past two or more decades.
- Overall species population growth of 3 percent each year between 2014 and 2016.
- Promising advances in juvenile seal survival enhancement research.
The decline that occurred in the NWHI has been attributed to a number of factors at various regions and time periods. However, low juvenile survival, likely related to inadequate prey availability, has been the primary driver of the decline during the past 25 years.
- Throughout Its Range
CITES Appendix I
- Throughout Its Range
- Throughout Its Range
- Throughout Its Range
Newborn monk seal pups are born black, while weaned pups and older seals are dark gray to brown on their back and light gray to yellowish brown on their belly.
Monk seals undergo a "catastrophic molt" about once per year, where they shed the top layer of their skin and fur (similar to elephant seals). Seals that spend a long time at sea foraging can grow algae on their fur. Those that look green haven't molted recently and may be getting ready to shed into a new silvery coat.
Most Hawaiian monk seals have unique natural markings, such as scars or natural bleach marks (white spots), on their fur which help identify them. Personnel authorized by NOAA Fisheries often apply tracking tags to their rear flippers. Tagging and tracking used in combination with identification of unique markings enable long-term monitoring of individuals.
Male and female monk seals are similar in size. The only way to confirm whether a seal is female or male is by looking at its belly.
Behavior and Diet
Hawaiian monk seals are "generalist" feeders, 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. They do not target most of the locally popular gamefish species such as ulua (giant trevally), pāpio (baby ulua), and ‘ō‘io (bonefish).
Hawaiian monk seals can hold their breath for up to 20 minutes and dive more than 1,800 feet; however, they usually dive an average of 6 minutes to depths of less than 200 feet to forage at the seafloor.
Hawaiian monk seals are mostly solitary and don't live in colonies like sea lions or other seals. But they do sometimes lie near each other—usually not close enough to make physical contact—in small groups. They usually sleep on beaches, sometimes for days at a time. They also occasionally sleep in small underwater caves.
Monk seals do not migrate seasonally, but some seals have traveled hundreds of miles in the open ocean. Individual seals often frequent the same beaches over and over, but they do not defend territories.
Where They Live
Hawaiian monk seals are found throughout the entire Hawaiian archipelago, a distance of 1,549 miles from Kure Atoll in the northwest to Hawaiʻi Island in the southeast. The majority of Hawaiian monk seals (about 1,100 individuals) live in the Northwestern Hawaiian Islands, and a much smaller population (about 300) lives in the main Hawaiian Islands. There have also been rare sightings of Hawaiian monk seals, as well as a single birth, at Johnston Atoll, the closest atoll southwest of the Hawaiian Islands.
Monk seals live in warm, subtropical waters and spend two-thirds of their time at sea. They use the waters surrounding atolls and islands and areas farther offshore on reefs and submerged banks; they also use deepwater coral beds as foraging habitat. When on land, monk seals breed and haul-out to rest, give birth, and molt on sand, corals, and volcanic rock shorelines. They prefer sandy, protected beaches surrounded by shallow waters for pupping.
Lifespan & Reproduction
Monk seals can live to over 30 years of age, but few live that long.
Monk seals mate in the water. The youngest documented female to give birth was 4 years old, but typically females begin reproducing at age 5 to 6 in the main Hawaiian Islands and age 7 to 10 in the Northwestern Hawaiian Islands.
Limited food intake by juvenile seals was the dominant factor driving the population decline in the Northwestern Hawaiian Islands for many years, and it remains a limiting factor for juvenile survival despite recent, positive signs that the population is stabilizing. In the NWHI, seals must compete for food with large populations of other apex predators, such as large jacks (carangids) and sharks. Shifts in ecosystem productivity, caused by global climate change and/or cyclical changes, may also contribute to food limitation.
Predation by Galapagos sharks on pre-weaned or recently weaned seal pups has become a major cause of injury and mortality specific to French Frigate Shoals in the Northwestern Hawaiian Islands. This is a unique and relatively recent type of seal mortality that appears to result from atypical behavior of a limited number of Galapagos sharks that prey on pups in near shore waters, often in just a few feet of water. Learn more about our monk seal pup protection efforts at French Frigate Shoals.
Hawaiian monk seals have one of the highest documented entanglement rates of any pinniped species, and pups and juveniles are the most often entangled. Marine debris and derelict fishing gear are chronic forms of pollution affecting monk seal habitat, particularly in the Northwestern Hawaiian Islands. The number of monk seals found entangled each year has generally remained unchanged. Undertaken by various agencies within NOAA, the U.S. Coast Guard, and other partners, marine debris removal efforts have extracted over 800 metric tons of debris in the NWHI since 1996, but accumulation rates of marine debris appear to remain constant.
Male Seal Aggression
A significant cause of female and juvenile monk seal mortality—and overall population decline—during the 1980s and early 1990s was by aggression from multiple male seals (especially at Laysan and Lisianski Islands). In other instances, single males have aggressively attacked and lethally injured recently weaned pups at French Frigate Shoals and Kure Atoll. NOAA Fisheries found that removal of specific aggressive males appears to be an effective method to address this threat. Other interventions include hazing of the aggressor, translocating young seals away from areas with the aggressive males, and treating injured seals as appropriate. Male aggression continues to be a concern, even though it tends to be episodic, geographically limited, and largely manageable provided necessary resources are available.
The loss of terrestrial habitat is a significant issue in the Northwestern Hawaiian Islands, which has mostly low-lying atolls (many islands less than 6.5 feet above sea level) subject to beach loss from storm erosion and sea level rise. Some significant habitat loss—such as the disappearance of Whale-Skate Island at French Frigate Shoals which was previously a primary pupping site—has already occurred, and sea level rise over the longer term may threaten a large portion of the resting and pupping habitat in the NWHI.
Since 1990, fishery management measures have eliminated interactions with monk seals in U.S.-managed commercial fisheries in the Northwestern Hawaiian Islands. But interactions in nearshore recreational and subsistence fisheries have occurred in the main Hawaiian Islands. Between 1976 and 2016, there have been 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 that participate in the three main Hawaiian Islands nearshore fisheries that may interact with monk seals: spearfishing, shorecasting, and gillnet fishing.
The primary diseases of concern to monk seals include distemper viruses (morbillivirus), West Nile virus, leptospirosis, and toxoplasmosis. There is also the threat of emergent diseases that have yet to make it to Hawai'i. The lack of antibodies in monk seals to these diseases makes them extremely vulnerable to potential infection. Since 2001, there have been a minimum of eight monk seal deaths from toxoplasmosis in the Hawaiian Islands, with at least three deaths occurring since 2014. This number is likely a significant underestimate of the true numbers of cases of this disease and its impact on the population.
Intentional feeding, disturbance of sleeping or resting seals, and/or other direct human interactions, such as swimming with juvenile seals, has become a serious concern for the main Hawaiian Islands population. Beaches that are popular for human recreation are increasingly used by monk seals for "hauling out" (resting) and molting, and some female monk seals are also pupping on popular recreational beaches. During these pupping events, mother-pup pairs remain on the beach to nurse for up to 7 weeks, at which time they're particularly vulnerable to human disturbance. This also presents a serious human safety concern, as mother seals are protective and aggressive. Human-seal interactions pose both a threat to human and seal safety and have necessitated the relocation of "conditioned" seals to remote locations in some cases.
Intentional killing of seals is an extreme example of negative human impacts in the main Hawaiian Islands. As of June 2017, at least four seals have died from apparent gunshots (including one pregnant female) and five from blunt force trauma. Foul play could not be ruled out as the cause of death for at least one other seal.
In the Spotlight
The Hawaiian monk seal is one of NOAA Fisheries’ Species in the Spotlight. This initiative is a concerted, agency-wide effort to spotlight and save the most highly at-risk marine species.
The Hawaiian monk seal is the last surviving species in its genus, and is endemic to the 1,500-mile long Hawaiian Islands archipelago, from Hawai'i Island to Kure Atoll.
Only about 1,400 Hawaiian monk seals are left in the world and their population is much lower than historic levels. With numbers that small, the life of every seal can be measured in its impact on the population growth or decline. Focused efforts and heightened partnerships are essential to stabilizing and preventing the extinction of the Hawaiian monk seal. There are inherent challenges to conserving and recovering the Hawaiian monk seal across such an expansive and remote area, especially with a range of ecological and anthropogenic threats affecting the population. Even so, NOAA Fisheries is better poised than ever to save Hawaiian monk seals from extinction and advance recovery.
Hawaiian monk seals face threats that include food limitations in the Northwestern Hawaiian Islands, especially for juveniles and sub-adults, entanglement in marine debris, and human interactions, especially in the main Hawaiian Islands. These human interactions include bycatch in fishing gear, mother-pup disturbance on beaches, and exposure to disease. Other threats to Hawaiian monk seals include loss of haul-out and pupping beaches due to erosion in the Northwestern Hawaiian Islands, disease outbreaks, male aggression towards females, and low genetic diversity.
Although much more work remains before the species is recovered, NOAA Fisheries and our partners have made significant headway in reducing extinction risks thus far. With more than 30 years of research and management experience with Hawaiian monk seals, NOAA Fisheries is currently working across the archipelago to address the population decline, and recovery actions are making a measurable difference—up to 30 percent of the monk seals in the population today are alive as a result of direct recovery interventions to save individual seals and allow them to have future offspring. Over this time period, the rate of monk seal population decline has been cut in half.
Saving this species starts with individual seals. Because of their value to the population growth potential, many monk seal recovery efforts focus on young and reproductive females. One example that highlights the success and impacts of these actions is R5AY, fondly known locally as "Honey Girl". This seal had seven pups, six of which were also female, by the time she was 15 years old. In 2012, she was found extremely emaciated with hook-and-line entanglement damage so extensive that NOAA Fisheries needed to intervene. Through this life-saving intervention, this story has a happy ending—Honey Girl survived and went on to successfully birth two more (female) pups to date. Without the efforts of NOAA Fisheries and our partners, Honey Girl, and other seals like her, would have died and the population trend would be much worse.
NOAA Fisheries is prepared with the plans, permits, and key stakeholder support in place to execute a new recovery initiative that is expected to reverse the species decline within 5 years. In 2014, NOAA Fisheries received a new ESA-MMPA permit to implement these new and expanded recovery actions. We also have reorganized the Monk Seal Recovery Team to assist with implementation and, with their help, released a Main Hawaiian Islands Hawaiian Monk Seal Management Plan (PDF, 72 pages) in 2016.
We will continue to work with our partners to implement priority recovery actions to accelerate monk seal recovery:
- Human Dimensions of Monk Seal Recovery Implementation and Community Empowerment including working with communities and stakeholders to recover the species, institute grant programs, and integrate Native Hawaiian and other traditional resource management values and practices into the efforts.
- Northwestern Hawaiian Island Research and Recovery Initiatives including restoring Northwestern Hawaiian Island Recovery Camps to optimal levels to maximize the number of seals benefiting from interventions and ensure robust data collection, while expanding recovery activities, and initiating critical research on the effects of climate change on monk seals.
- Health Assessment, Monitoring, and Emerging Disease Research and Prevention including increased disease monitoring and health assessments, research on diseases and mitigation strategies, implementation of a vaccination plan to prevent disease outbreaks, and establishing a network of partners to prevent and manage the threats of disease.
- Research, Management, and Mitigation of Human-Seal Interactions by developing a consortium of partners to mitigate seal-fisheries interactions, developing tools and strategies to address dangerous aberrant behaviors in monk seals, and implementing a multi-faceted social marketing strategy to effectively promote co-existence around monk seals.
- Hawaiian Monk Seal Recovery Program Infrastructure including hiring additional staff, equipment, tools, and consumables to fully implement recovery initiatives.
NOAA Fisheries is at a crucial juncture where continued commitment and investment in new monk seal recovery efforts will yield significant benefits for both monk seals and our stakeholders, including local fisheries and communities. We are developing a 5-year plan of action for this species that builds on the recovery plan and details the focused efforts that are needed over the next 5 years. Through continued commitment and dedication, we can reverse population trends and increase the chances that this rare seal will survive, and future generations can enjoy and co-exist with monk seals—like R5AY Honey Girl and her pups—for years to come.
Hawaiian monk seals are protected under the Endangered Species Act, the Marine Mammal Protection Act, and Hawai'i state law. They have been listed as endangered under the ESA since 1976. The Hawaiian monk seal is endemic to the Hawaiian Islands archipelago and Johnston Atoll, meaning they are native and exist nowhere else on Earth. NOAA Fisheries is working to protect this species in many ways, with the goal that its population will increase.
Recovery Planning and Implementation
Under the ESA, NOAA Fisheries is required to develop and implement recovery plans for the conservation and survival of listed species. The ultimate goal of the Recovery Plan for the Hawaiian Monk Seal is to the recover the species, with an interim goal of down-listing its status from endangered to threatened.
The major actions in the recovery plan are:
Investigate and mitigate factors affecting food limitation.
Prevent entanglement of monk seals.
Reduce shark predation on monk seals.
Conserve Hawaiian monk seal habitat.
Reduce Hawaiian monk seal interaction with fisheries.
Reduce male aggression toward pups/immature seals and adult females.
Reduce the likelihood of human disturbance.
Investigate and develop response to biotoxin impacts.
Reduce impacts from compromised and grounded vessels.
Reduce the impact of contaminants.
Continue population monitoring and research.
Create a Main Hawaiian Islands Hawaiian Monk Seal Management Plan (PDF, 72 pages).
Implement the Recovery Program for the Hawaiian monk seal.
NOAA Fisheries is committed to implementing the revised Hawaiian Monk Seal Recovery Plan, focusing on the overarching recovery strategies listed above. Actions being undertaken to implement the plan include:
- Coordination of NOAA, non-governmental organizations, and other federal, state, and local agencies to facilitate monk seal recovery.
- Reduction of mortality factors, including shark predation, male aggression, and risk of exposure to infectious diseases.
- Conservation of monk seal habitat.
- Development of comprehensive outreach and education programs focused on minimizing human disturbance and other adverse impacts and maximizing public support for monk seal conservation.
- Coordination of volunteer groups in the main Hawaiian Islands to facilitate monitoring and response for Hawaiian monk seal pupping events and haul-outs.
In recent years, NOAA Fisheries has developed additional strategic implementation plans that focus on partnerships and collaboration, and on issues affecting the main Hawaiian Islands monk seal population. These include:
- Species in the Spotlight Priority Actions: 2016-2020
- Main Hawaiian Islands Monk Seal Management Plan (PDF, 72 pages)
- Hawaiian Monk Seal 5-Year Review: Summary and Evaluation
Once a species is listed under the ESA, NOAA Fisheries evaluates and identifies whether any areas meet the definition of critical habitat. Those areas may be designated as critical habitat through a rulemaking process.
The designation of an area as critical habitat does not create a closed area, marine protected area, refuge, wilderness reserve, preservation, or other conservation area; nor does the designation affect land ownership. Federal agencies that undertake, fund, or permit activities that may affect these designated critical habitat areas are required to consult with NOAA Fisheries to ensure that their actions do not adversely modify or destroy designated critical habitat.
In 2008, NOAA Fisheries received a petition to revise critical habitat for the Hawaiian monk seal—the terrestrial and marine areas the mammal needs to survive and recover—requesting the 1988 designation be extended in the Northwestern Hawaiian Islands and include new areas in the main Hawaiian Islands. Since the the original critical habitat designation, new information became available regarding monk seal habitat use revealing that monk seals forage at greater depths than previously thought and that they successfully utilize habitat in the main Hawaiian Islands.
NOAA Fisheries revised the Hawaiian monk seal critical habitat to further describe habitat features and areas that support Hawaiian monk seal conservation. Specific areas designated include 16 occupied areas within the range of the Hawaiian monk seal. These areas contain one or more features essential to Hawaiian monk seal conservation, including:
- Preferred pupping and nursing areas.
- Significant haul-out areas.
- Marine foraging areas out to 200 meters in depth.
In 2015, NOAA Fisheries issued the final rule to revise the Hawaiian monk seal critical habitat expanding the previous designation in the Northwestern Hawaiian Islands and identifying new key beach areas and marine-foraging areas in the main Hawaiian Islands.
Areas included in the final Critical habitat designation
Northwestern Hawaiian Islands
Critical habitat in the Northwestern Hawaiian Islands includes all beach areas, sand spits, and islets, including all beach crest vegetation to its deepest extent inland as well as the seafloor and marine habitat 10 meters in height above the seafloor from the shoreline out to the 200-meter depth contour around:
Pearl and Hermes Reef
French Frigate Shoals
Main Hawaiian Islands
Critical habitat in the Main Hawaiian Islands includes the seafloor and marine habitat to 10 meters above the seafloor from the 200-meter depth contour through the shoreline and extending into terrestrial habitat 5 meters inland from the shoreline between identified boundary points around:
Kaula Island (includes marine habitat only)
Niʻihau (includes marine habitat from 10 to 200 meters in depth)
Maui Nui (including Kahoʻolawe, Lānaʻi, Maui, and Molokaʻi)
For each threat identified as a source of negative impacts to monk seals (see the Threats section on Overview), NOAA Fisheries, with assistance from our partners, has developed and implemented targeted conservation and recovery efforts to address each threat. We have also developed broader management and outreach strategies that seek to engage the general public as an active part of monk seal recovery.
Responding to Strandings and Haul-Outs
The Pacific Islands Region Marine Mammal Response Network responds to strandings and haul-outs of all marine mammals, including monk seals. NOAA Fisheries manages the Network in partnership with several government agencies, including the Hawai'i Department of Land and Natural Resources, the Hawaiian Islands Humpback Whale National Marine Sanctuary, University of Hawaiʻi at Mānoa, the U.S. Coast Guard, and the National Park Service. Network volunteers, managed directly by NOAA Fisheries and/or our partners, donate thousands of hours to public education and day-to-day human-seal management in the main Hawaiian Islands.
Volunteers assist with the following:
- Responding to seals that haul out to rest by setting up "seal resting areas" and using them as a platform to educate the public about monk seal biology, conservation, and responsible wildlife viewing practices, which helps to deter potential disturbance.
- Monitoring monk seal pupping and molting events.
- Reporting seals in distress (due to fish hook injury, entanglement, or otherwise) and standing by until arrival of certified NOAA assistance.
- Searching for and long-term monitoring of seals of concern (seals reported with injuries, hookings, entanglements, behavioral concerns, etc.) and providing NOAA with observation data on these animals.
- Visiting schools, festivals, local businesses, and other venues to provide public education and outreach regarding the ecology and conservation of Hawaiian monk seals.
Implementing Targeted Conservation Strategies
Our work includes:
- Translocation of seals to other islands or atolls with improved foraging conditions.
- Captive rehabilitation of malnourished animals.
Of note, NOAA’s partnership with Ke Kai Ola, a facility built by The Marine Mammal Center in Kona, Hawai'i in 2014, has opened up a new world of rehabilitation possibilities for monk seals. In 2017, Ke Kai Ola was recognized as a NOAA Species in the Spotlight Hero for their contributions to monk seal conservation and recovery.
Our work includes:
- Translocation of newly weaned pups to areas with low shark predation risk.
- Limited lethal removal of Galapagos sharks from nearshore pupping habitat.
Entanglement in Marine Debris
Our work includes:
- Disentangling seals and removal of marine debris from beaches and marine habitat.
Adult Male Aggression
Our work includes:
- Treating injured seals when appropriate.
- Hazing of identified aggressors.
- Translocating pups from areas where aggressive males frequent.
- Removing the aggressive males.
Our work includes:
- Continued monitoring to assist in planning mitigation strategies necessary, particularly for the Northwestern Hawaiian Islands.
Human-Seal Interactions (Including Fisheries)
Our work includes:
- Education and outreach to prevent/minimize human-seal interactions.
- Applying behavioral conditioning, translocating, or bringing into captivity seals that pose a human safety risk.
- Dehooking seals.
- Encouraging fishermen to use barbless hooks and to avoid fishing when a seal is in the area.
NOAA Fisheries partners with the Hawai'i Department of Land and Natural Resources' Division of Aquatic Resources to increase fishermen's awareness and promote seal-friendly fishing practices through a joint effort called the Barbless Circle Hook Project. This work is funded in part via an ESA Section 6 Program grant. Efforts by the Hawai’i Department of Land and Natural Resources have focused on response support and community outreach and education, especially outreach to fishermen and other local ocean users.
Our work includes:
Monitoring health, including disease, parasitic infection, and toxin screening.
Providing appropriate medical treatment (including deworming).
Continuing vaccination research and response planning.
Coordinating Volunteer Participation
We coordinate volunteer groups in the main Hawaiian Islands to assist with monitoring and response for monk seal pupping events and haul-outs. Volunteers help put up signs near hauled-out monk seals to help alert the public to their presence and help prevent disturbance. They also educate beachgoers about monk seal natural history and responsible viewing of this endangered species.
Volunteers also assist NOAA’s monk seal researchers to assess the population of this endangered species by counting seals on beaches across all of the main Hawaiian Islands.
For more information or to apply to be a volunteer, contact your island's Marine Mammal Response Coordinator.
Evaluating the Environmental, Social, and Economic Effects of the Monk Seal Recovery Program
In compliance with the National Environmental Policy Act, NOAA Fisheries prepared and published a programmatic environmental impact statement in 2014. This comprehensive review of the monk seal recovery program describes and analyzes a suite of research and enhancement (management) actions proposed by NOAA Fisheries to promote recovery of endangered Hawaiian monk seals.
Key Actions and Documents
Incidental Take Authorization: U.S. Navy Hawaii-Southern California Training and Testing (HSTT) (2018-2023)
Incidental Take Authorization: Lamont-Doherty Earth Observatory Marine Geophysical Survey in the North Pacific Ocean
Incidental Take Authorization: U.S. Navy Operations of Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) Sonar (beginning in
Incidental Take Authorization: U.S. Navy Hawaii Southern California Training and Testing (HSTT) (2013-2018)
NOAA Fisheries uses innovative science to explore monk seal biology and interactions with humans and the environment, and apply the best available science to guide our management and recovery plans for monk seals. Our Hawaiian Monk Seal Research Program leads these efforts.
The Hawaiian Monk Seal Research Program
Our overarching goal is to achieve an optimal and sustainable monk seal population. This program is organized into three teams that work together and with outside collaborators on five key research and conservation initiatives designed to address the recovery strategies outlined in the Hawaiian Monk Seal Recovery Plan.
Research and Conservation Initiatives
Five key research and conservation initiatives are undertaken by integrated teams of Hawaiian Monk Seal Research Program personnel and collaborators to further identify impediments to survival and respond with appropriate science-based conservation measures.
Population Assessment and Enhancement Research
The work performed under this initiative provides annual high-resolution information from each monk seal subpopulation required to assess the species status, population trends, and current threats. Survival enhancement activities are implemented and tracked to evaluate their effectiveness.
Foraging and Fisheries Interactions Research
This initiative aims to characterize the foraging ecology of monk seals by evaluating monk seal diet, foraging behavior and habitat use, and via examination of ecological links affecting monk seal foraging. Additional studies include quantifying the level and types of direct and indirect interactions with fisheries and determining ways to mitigate them to the benefit of both seals and fishermen.
Survival Enhancement Research and Activities
This initiative focuses on developing effective tools and activities to mitigate threats, and thus enhance monk seal survival throughout its range.
Health and Disease Research and Emergency Response
Our scientists investigate the role infectious diseases, parasites, and toxins play in the recovery of monk seal populations. Other activities include critical response for compromised seals (e.g., hooked, entangled, sick, and/or injured).
Our scientists use molecular techniques to advance knowledge of Hawaiian monk seal health, population dynamics, and diet.
Population Status/Stock Assessment
The prolonged and steep decline of Hawaiian monk seal populations has occurred more or less continuously since the 1950s. However, there have been some relatively recent encouraging developments, including:
Promising advances in juvenile seal survival enhancement research and local community engagement.
The best estimate of the current total Hawaiian monk seal population is 1,400 seals—about 1,100 in the Northwestern Hawaiian Islands (from Nihoa to Kure Atoll), and about 300 in the main Hawaiian Islands (from Ni'ihau to Hawai'i Island). The most recent annual population assessment shows that the Hawaiian monk seal, bucking past trends, has increased in numbers by 3 percent annually for the past three years. While numbers have increased since 2013, the long-term decline in abundance at the six main Northwestern Hawaiian Islands sites—French Frigate Shoals, Laysan Island, Lisianski Island, Pearl and Hermes Reef, Midway Atoll, and Kure Atoll—remains concerning.
Hawaiian Monk Seal Movements Among Islands and Atolls - It was once assumed that monk seals did not travel between the Northwestern Hawaiian Islands and the main Hawaiian Islands, but research now shows that in rare cases they do, and even make it down to Johnston Atoll.
The Role of Diet as a Driver of Divergent Population Trends - Monk seals in the Northwestern Hawaiian Islands and main Hawaiian Islands eat a similar diet, but seals in the main Hawaiian Islands may experience less competition for food. In addition, prey that may be more bountiful and better quality, allowing the main Hawaiian Islands population to increase while the Northwestern Hawaiian Islands population continues to decrease.
Non-Lethal Efforts to Deter Shark Predation of Monk Seal Pups - Monk seal pups at French Frigate Shoals are heavily preyed upon by Galapagos sharks, but it’s unclear if non-lethal efforts to deter this behavior are effective. However, translocating newly weaned pups to areas with less shark predation has proven beneficial to pup survival.
Translocation Strategy for Improving Juvenile Survival of Hawaiian Monk Seals - Research suggests that immature monk seals may benefit (in terms of survival) from being moved from areas of lower to higher juvenile survival.
Education and Outreach
Volunteers help put up signs near hauled-out monk seals to help protect them from disturbance and educate beachgoers about monk seal natural history and responsible viewing of this endangered species. For more information or to apply to be a volunteer, contact your island's Marine Mammal Response Coordinator:
Hawaiʻi Island: (808) 987-0765
Kauaʻi: (808) 651-7668
Maui and Lānaʻi: (808) 292-2372
Molokaʻi: (808) 553-5555
Oʻahu: (808) 220-7802
Watch our video about monk seal rehabilitation and the Ke Kai Ola Marine Mammal Center and hospital.
And there's good news...since we produced this video, NOAA Fisheries' lead Hawaiian monk seal scientist, Charles Littnan, and his team recently crunched the numbers and have found a very robust way to include more data to present a complete range-wide population estimate, driving the estimated number of Hawaiian monk seals up from 1,100 to about 1,400.
In 2015, NOAA Fisheries announced a new program to focus and redouble our efforts to protect eight…
The plan includes years of work and input from stakeholders and partners, drawing on outcomes from…
Data & Maps
The Recovery Action Database tracks the implementation of recovery actions from Endangered Species…
Researchers examine Instagram posts for human interactions with the endangered Hawaiian monk seal.
Our team surveys and cleans up derelict fishing nets and ocean plastics from the reef and shoreline habitats of the Northwestern Hawaiian Islands, an ecologically and culturally significant area.