Frequent Questions—Maine Seal Stranding Event

What was announced?

NOAA Fisheries has declared an Unusual Mortality Event (UME) for elevated harbor and gray seal strandings along the southern and central coast of Maine. This event began in June 2022. In June and July of 2022, seals tested positive for for highly pathogenic avian influenza (HPAI). You can track seal stranding numbers on our Maine Pinniped UME webpage.

What is an Unusual Mortality Event?

An Unusual Mortality Event (UME) is defined under the Marine Mammal Protection Act as a stranding event that is unexpected, involves a significant die-off of any marine mammal population, and demands immediate response. There are seven criteria used to determine whether a mortality event is “unusual.” If the Working Group on Marine Mammal Unusual Mortality Events (Working Group), a group of marine mammal health experts, determines that an event meets one or more of the criteria, it forwards a recommendation to NOAA’s Assistant Administrator for Fisheries to declare an UME.

What criteria have been met in this event?

In this case, the Working Group concluded that one of the seven criteria has been met:

• Affected animals exhibit similar or unusual pathologic findings, behavior patterns, clinical signs, or general physical condition (e.g., blubber thickness) (Criterion 5).

The Working Group will continue to monitor stranding rates, as well as all other findings, and may determine that additional criteria are met as the investigation continues.

How widespread is this event for seals?

Currently, increased numbers of dead harbor and gray seals were detected along the southern and mid coast of Maine from Biddeford to Boothbay. Additionally, the Marine Mammal Stranding Network was put on alert from Maine through New York to monitor for increases in stranded seals along the northeast Atlantic coast.

What are the symptoms displayed by the sick seals?

In live seals, symptoms include lethargy, coughing, discharge from the eyes and nose, seizures, and death. Seals with neurological signs including seizures are dying quickly, usually within hours.

What are the findings in stranded animals?

Testing of samples has found some harbor and gray seals positive for highly pathogenic avian influenza (HPAI) H5N1, which is a zoonotic disease that has the potential to spread between animals and people (and their pets). However the health risk posed by the current avian flu to the general public is low. Full or partial necropsy examinations were conducted on several seals, including those that died in care or were euthanized. Many dead seals that were originally reported were decomposed, which limits the ability to analyze samples. Recent research on these seals found that the virus was most likely transmitted from wild birds to seals twice for at least two distinct HPAI H5N1 lineages and likely occurred through environmental transmission of shed virus. It is unlikely that multiple seals acquired the viruses through predation or scavenging of an infected source (such as an infected bird) at this scale, as birds are not a typical food source for harbor or gray seals. The current data from the 2022 samples does not support seal-to-seal transmission as a primary route of infection.

What can I do to help the investigation?

The most important step members of the public can take to assist investigators is to immediately report any sightings of seals in distress or dead stranded seals. In Maine, please call the Maine Marine Animal Reporting Hotline at (800) 532-9551. To report seal strandings south of Maine, please call the NOAA Fisheries Stranding Hotline: (866) 755-6622. Do not approach or touch the seal, and keep your pets far away.

Have other mammals or animals been affected by this die-off event?

Yes, there is an ongoing highly pathogenic avian influenza (HPAI) H5N1 event in domestic birds and wild birds and some species of terrestrial mammals across the United States (e.g., red fox, striped skunk, opossum, raccoon, bobcat, American mink, coyote, fisher cat, bear, river otter, and others). More information can be found at USDA, NWHC, CDC, and State of Maine. Samples from a stranded bottlenose dolphin in Florida that had stranded in March 2022 tested positive for HPAI. This dolphin had brain lesions similar to the seals. This is the first report of HPAI in a dolphin in the United States. Additionally, several seals and a dolphin have tested positive for HPAI in Quebec, Canada. 

Is this influenza outbreak in seals associated with the larger HPAI outbreak in North America?

The current outbreak of HPAI in North America was first detected in early winter 2021 in Newfoundland and Labrador, Canada. The first detections in Maine waterfowl were in February 2022. HPAI H5N1 has now been confirmed in nearly all U.S. states and Canada provinces, in commercial poultry, backyard flocks, many species of wild birds, and several species of mammals.

What do I do if I find a dead bird in Maine?

If you find a dead bird, it is best to wear gloves if interacting with the carcass, including picking it up for disposal. Maine Department of Inland Fisheries and Wildlife encourages the public to report five or more dead birds in a small area to the Department for further investigation. If you need to report a dead bird(s), please contact a regional wildlife biologist. Because of the impact on birds of prey, if someone from the public finds an ill or dead bald eagle, owl, or other bird of prey, you are encouraged to notify the Department and eagles found dead are to be collected by Maine Department of Inland Fisheries and Wildlife staff only. If an eagle is found, please call Maine Police dispatch at (207) 624-7076 or the Gray Regional Office at (207) 287-2345.

What are influenza viruses?

There are three types of influenza viruses: A, B and C. Avian influenza A viruses, which include the virus that has been detected in seals in 2022, occasionally cross over the species barrier from birds and cause clinical disease and epidemics in people and other mammalian species, including seals (these are known as “zoonotic diseases” meaning they have the potential to spread between animals and people (and their pets). Influenza B viruses are primarily a virus in people with no known wildlife reservoir, and cause clinical disease epidemics in people. However, they have been isolated from apparently healthy gray and harbor seals in the North Sea in Europe. Influenza C is a virus that infects people and may cause a mild respiratory illness but is not thought to cause epidemics in people.

Influenza A viruses are divided into subtypes based on two proteins on the surface of the virus: hemagglutinin (H) and the neuraminidase (N). There are 16 different hemagglutinin subtypes and 9 different neuraminidase subtypes. Influenza A viruses can be further broken down into different strains. Subtypes may be species specific, so not all subtypes are found in all species. Both Influenza A and Influenza B viruses have been documented to cause illness and deaths in seals in North America and in Europe. Learn more about flu viruses 

What is bird flu?

Avian influenza, or bird flu, refers to a respiratory disease caused by infection with a type of influenza virus. Avian flu viruses normally spread among wild water birds, such as ducks and geese. These viruses can spread to domestic poultry, such as chickens, ducks, geese, and guinea hens. Avian flu viruses do not normally make humans sick but human infections with avian flu viruses have occurred. People who have regular contact with poultry or wild birds are most at risk.

What is the risk to humans from the influenza virus?

Some influenza viruses are “zoonotic diseases,” which means they can be shared between animals and people. Influenza A viruses especially have a relatively high rate of mutation, or change, which may allow them to cross species barriers and may cause severe disease in their new hosts. For this reason, the Centers for Disease Control, the National Wildlife Health Center, National Institute of Health, state agencies, and other organizations like NOAA monitor events involving animal influenza viruses very closely, and advise the public to take precautions for themselves and their pets.

What is the risk to humans from the H5N1 Highly Pathogenic Avian Influenza?

According to the CDC, the health risk posed to the general public is low; however, precautions are recommended.

Are there any risks to pets?

Yes. Dogs and cats also share infectious diseases with marine mammals and should not be allowed to approach live or dead marine mammals or to consume dead marine mammals or their parts. Dogs are susceptible to a canine influenza virus. Additionally, sick seals that do not feel well may bite you or your pet if you get too close. NOAA Fisheries recommends contacting your pet’s veterinarian to discuss the potential risk to pets in your local area, or if your pet bites or is bitten by a seal.

What should I do to protect myself and my pets against these viruses?

You should never approach or allow a pet to approach a live or dead marine mammal. Seals, like other marine mammals (dolphins, whales, and sea lions), are protected under the Marine Mammal Protection Act. It is important that people and their pets maintain a safe distance of 150 feet from these animals so as not to disturb the animal, which may be just resting on the beach, and to avoid injury to themselves, their pets, or the seals. While seals look cute, they are wild animals and can transmit disease. Some safe viewing tips:

• Stay at least 150 feet away from seals or other marine mammals.

• Keep dogs on a leash and don’t allow them to approach seals. Seals and dogs can easily infect each other with diseases since they are closely related species.  

• Call NOAA Fisheries’ stranding hotline at (866) 755-NOAA (6622), or a local marine mammal stranding network member or visit our Stranding Network web page for local contact information.

Has influenza virus ever been detected in seals in the northeastern United States?

Yes, Influenza A viruses have been detected previously, both during outbreaks in which the virus caused clinical disease and/or mortality events in seals, and in apparently healthy individuals not associated with any outbreak.

Examples of previous influenza events and results of biomonitoring of seals over the past 40 years are below, with most recent events listed first:

• 2013–present: various forms of influenza detected during health assessments of gray seals with no clinical disease
• 2011: H3N8 isolated from harbor seals during the Unusual Mortality Event in Maine, New Hampshire, and Massachusetts
• 2006: H3N8 isolated from a by-caught harp seal with no clinical disease in Northeast United States
• 1991-1992: Influenza A viruses isolated from seals that died of pneumonia in Cape Cod, Massachusetts—H4N6 isolated from lung of two seals; H3N3 isolated from lung of three seals. These viruses were isolated from seals that died during a mortality event. The H3N3 strain identified here was more closely related to one that infects birds than any other species
• 1982–1983: H4N5 harbor seal mortality event in the Northeast United States
• 1979–1980: H7N7 harbor seal mortality event in the Northeast United States 

Has influenza ever been detected in seals outside of the northeastern United States?

Yes, influenza A viruses have been detected in marine mammals in other parts of the world.

2023: H5N1 in a sea lion and sea otter in Chile

2022: H5N1 in harbor and gray seals in Canada, harbor and gray seals in Scotland, sea lions in Peru, harbor porpoise in Sweden, bottlenose dolphin in Florida, common dolphin in Peru

2021: H10N7 isolated from a harbor seal in British Columbia

2021: H5N8 detected in 4 harbor seals and 1 gray seal after exposure to an infected swan in the United Kingdom; two additional harbor seals were found to have H5N8 in the Wadden Sea

2017: H3N8 isolated from a gray seal in the UK

2014–2015: H10N7 harbor and gray seal mortality event in the North Sea

2012: H4N6 isolated from Caspian seals in Russia

2010 and 2022: H1N1 detected in elephant seals in California

How does the influenza virus spread among seals?

Influenza viruses are usually spread through inhalation of respiratory particles, direct contact with feces, or between animals, including between mothers and pups. Animals can also be exposed to the virus through other entryways such as the eyes, mouth, stomach, skin wounds, and the urogenital tract.

How do seals catch influenza?

While this is still an area of active investigation, it is believed that most cases initiate from waterfowl or seabirds, which are the natural reservoirs for a diverse range of Influenza A variants. Seals can be exposed by being close to birds through respiratory droplets or exposure to infected bird feces. Once a new variant of influenza has entered into a seal population, it is then often able to spread from seal to seal.

How do influenza viruses affect seals?

The most common organs affected are the lungs and brain. Sick animals may appear thin, have respiratory clinical signs such as coughing, or difficulty breathing and may exhibit teary eyes, lethargy, and/or abnormal behavior due to a brain infection.

Is there anything you can do to protect the seals?

One of the challenges of wildlife management is managing large, healthy populations; harbor seals in this region are one such group of wildlife. We have instituted testing and management within our rehabilitation facilities to reduce the potential spread of the disease in rehabilitation centers and to reduce exposure for employees and their pets. The public can also help by keeping themselves and pets far away from seals in the wild.

If the animals are sick, when does the Marine Mammal Stranding Network consider euthanasia for marine mammals?

Situations that may necessitate the consideration of euthanasia include an animal’s suffering with severe injuries (either internal or external) or illness (e.g., disease or poor body condition). If an animal has a serious injury or illness from which recovery is unlikely, euthanasia may be the best and most humane course of action to alleviate its prolonged suffering. Each scenario will be carefully evaluated on a case-by-case basis to provide the most humane outcome for the individual animal. The decision to euthanize a marine mammal is made by the NOAA Fisheries Regional Stranding Coordinator, the local Stranding Network group, the attending veterinarian, the Marine Mammal Health and Stranding Response Program staff, and/or other management agencies, depending upon the circumstances.

Does euthanasia cause pain to seals? How do they react when euthanized? How long does euthanasia take?

Seals are generally given a sedative to reduce pain and stress during the administration of euthanasia drugs. The sedatives will often result in the animal being unconscious or “asleep” prior to euthanasia. When euthanizing by chemical methods (e.g., barbiturates), the time of death varies for each case—from seconds to several minutes. Stranding Network veterinarians and/or NOAA Fisheries designate authorized responders that have the experience and training to relieve unnecessary pain and suffering through euthanasia, if the recovery and return to the wild of a stranded marine mammal is not possible. The goal of euthanasia is to make the death of an animal as painless, quick, and free of distress as possible by using the best and most effective method for the specific situation.

Are seal rehabilitation hospitals closing or closed to new patients?

Marine Mammals of Maine, the local rehabilitation hospital, had closed during the peak of this disease event. Currently, they are open and new seals are admitted on a case-by-case basis and are quarantined and tested upon arrival. Other facilities in the Greater Atlantic Region may pause intakes of animals while diagnostically screening current patients, or may need to limit or restrict new patients to be able to enact the stricter quarantine precautions that an identified infectious disease requires.

What guidance has been provided to the marine mammal stranding response teams regarding handling seals and potential human health impacts?

The Network normally follows safety precautions for handling stranded seals as provided in each organization's safety plans and NOAA Fisheries’ “Best Practices for Marine Mammal Stranding Response, Rehabilitation, and Release.” In addition, we have distributed fact sheets and other materials on avian influenza and infectious disease prevention to our network responders.

Does eating seafood pose a risk?

Influenza viruses do not cause disease in fish so there is no risk of catching this virus by eating fish.

What are the current harbor and gray seal populations along the Northeast coast?

The Western North Atlantic stocks of Atlantic harbor and gray seals are involved in this unusual mortality event. Harbor and gray seals involved in this event are not listed as threatened or endangered under the Endangered Species Act.

Atlantic Harbor Seals

The Western North Atlantic stock of Atlantic harbor seals primarily ranges from the eastern Canadian Arctic and Greenland south to southern New England and New York, and occasionally into the Carolinas. The estimated abundance of this stock in the U.S. is 75,834 from the 2019 Stock Assessment Report.

Atlantic Gray Seals

The Western North Atlantic stock of Atlantic gray seals primarily ranges from Labrador Canada to New Jersey. The estimated abundance of this stock in the U.S. is 27,131 from the 2019 Stock Assessment Report.

Where can I find additional information on harbor and gray seals? 

• Harbor seals
• Gray seals
• Seal Viewing Guidelines

What should people do if they see a person or animal harassing a seal?

To report violations or for more information on NOAA’s Office of Law Enforcement call the toll- free number: (800) 853-1964.

How many seal UMEs have previously occurred along the Northeast coast?

Five previous UMEs involving harbor and/or gray seals have occurred along the Northeast coast in 1991–1992, 2003, 2006–2007; 2011–2012, and 2018–2021 respectively. The 1991–1992 UME was localized in Massachusetts, involved ~24 harbor seals and the cause of this event was suspected avian influenza virus infection. The 2003 UME was localized in Maine and involved ~42 harbor seals and the cause was undetermined. The 2006–2007 UME extended from Maine to Virginia, involved ~1,500 seals including harbor and gray seals, and the cause of that event was phocine distemper virus. The 2011–2012 UME extended from Maine to Massachusetts, involved~784 seals including harbor and gray seals, and the cause of that event was avian influenza. The 2018–2021 UME extended from Maine to New Jersey, involved ~3,000 seals including harbor, gray and harp seals, and the cause of that event was phocine distemper virus.

What can I do to help the response to the UME?

The most important step members of the public can take to assist investigators is to immediately report any sightings of seals in distress or dead stranded seals. In Maine, please call the Maine Marine Animal Reporting Hotline at (800) 532-9551. To report seal strandings south of Maine, please call the NOAA Fisheries Stranding Hotline: (866) 755-6622.  Do not approach or touch the seal.

The public may use Pay.gov to donate to the UME Contingency Fund for this or other UMEs and help cover costs incurred by the Marine Mammal Stranding Network. We also encourage you to reach out to your local stranding network organization to see how they could use your support. 

What is the UME Contingency Fund?

MMPA section 405 (16 USC-1421d) establishes the Marine Mammal Unusual Mortality Event Fund describing its purposes and how the public can donate to the fund. According to the MMPA, the fund: “shall be available only for use by the Secretary of Commerce, in consultation with the Secretary of the Interior:

• To compensate persons for special costs incurred in acting in accordance with the contingency plan issued under section 1421c(b) of this title or under the direction of an Onsite Coordinator for an unusual mortality event.
• For reimbursing any stranding network participant for costs incurred in preparing and transporting tissues collected with respect to an unusual mortality event for the Tissue Bank.
• For care and maintenance of marine mammals seized under section 1374(c)(2)(D) of this title.”

The National Contingency Plan for Response to Unusual Marine Mammal Mortality Events outlines the types of expenses that are reimbursable under the fund and the process for requesting reimbursement. 

Learn more about the UME Contingency Fund.

How can deposits be made into the UME Contingency Fund?

The following can be deposited into the fund:

• Amounts appropriated to the fund.
• Other amounts appropriated to the Secretary for use with respect to UMEs.
• Amounts received by the United States in the form of gifts, devises, and bequests under subsection (d) of section 405(d) of the MMPA.

The public may use Pay.gov to donate to the UME Contingency Fund for this or other UMEs and help cover costs incurred by the Marine Mammal Stranding Network.