Skip to Page Content
banner top art gif
office title gif
NOAA Fisheries
Office of Protected Resources
Acropora palmata thicket on Mona Island, Puerto Rico. Andy Bruckner, 1996Coho salmon painting, Canadian Dept of Fisheries and OceansMonk seal, C.E. BowlbyHumpback whale, Dr. Lou Herman
banner art gif
Programs
Conservation, Protection, & Recovery
Species of Concern
Listing of Species
Recovery of Species
Marine Mammal Conservation Plans
Cooperation with States
Grants to Tribes
Interagency Consultation
   Biological Opinions

Human Impacts
Fisheries Interactions (bycatch)
Ocean Sound/Acoustics
Ship Strikes
Viewing Wildlife

International Cooperation

Marine Mammal Health & Stranding
Marine Mammal National Database
National Tissue Bank
Prescott Grants
Unusual Mortality Events
  Contact OPR
Glossary
OPR Site Map

inner curve gif

Declaration of 2011 Pinniped Unusual Mortality Event in the Northeast


Harbor Seal in the water
Harbor Seal
(Phoca vitulina)
Photo: NOAA

Overview
On November 3, 2011, a marine mammal "Unusual Mortality Event" was declared for Maine, New Hampshire and northern Massachusetts for a high number of seal deaths between September 1, 2011 and the present. As of September 1, 2011, 162 harbor seals (Phoca vitulina) are included in the Unusual Mortality Event, most under six months old. The Unusual Mortality Event is ongoing and all mortalities are being thoroughly investigated to the extent possible. The majority of cases have involved young of the year and many have similar skin lesions (ulcerative dermatitis). Unlike historical young of the year harbor seal mortalities, which are often attributed to malnutrition, many of these animals are in good body condition.

NOAA's National Marine Fisheries Service's Northeast Regional Office (NERO), in collaboration with the New England Aquarium's Marine Animal Rescue Program and the University of New England's Marine Animal Rescue Center, requested a formal consultation with the Working Group on Marine Mammal Unusual Mortality Events (Working Group) resulting in the declaration of an Unusual Mortality Event on November 3, 2011. For more information on the process to declare this Unusual Mortality Event, see our Q&A section.

As part of the Unusual Mortality Event investigation process, an independent team of scientists has been assembled to coordinate with the Working Group to review and interpret the data collected and to develop a plan for further investigation into the recent mortalities. These rigorous investigations may take several more months to complete. However, NOAA will make every effort to make information available to the public as soon as it is scientifically appropriate and possible.

During the Unusual Mortality Event investigation, Influenza A H3N8 was confirmed in five (5) harbor seals that stranded in New Hampshire in mid-September/early October 2011. Additional samples from animals stranded in Maine, New Hampshire, and Massachusetts are being evaluated. These test results are only indicative of the five animals tested, and additional evaluations are underway to determine whether the influenza virus has played a role in the overall mortalities that have occurred throughout this timeframe and area. Please see our Q&A section below for more information.

This particular virus subtype, while found in horses, birds, seals, and dogs, has not been detected in humans in recent decades. While the risk to humans from this virus is low (according to the Centers for Disease Control and National Wildlife Health Center), we want to remind people to keep a safe distance from seals they encounter on the beach and in the water and to keep their pets away from these animals. If they see an animal that looks sick, please report it to the NOAA stranding hotline or local stranding network member.

NOAA Fisheries is collaborating with Federal and State public and wildlife health officials in Massachusetts, Maine, and New Hampshire. The investigation is being coordinated with agriculture, wildlife and human health officials to evaluate the risks to poultry, dogs, wild carnivores, and people, as well as the potential role of wild birds in these infections. Guidance is being provided to stranding responders to minimize the risk of disease transmission to personnel and other species. Our thanks to all of our partners in this effort, including:

  • USGS National Wildlife Health Center
  • New England Aquarium Marine Mammal Rescue Program
  • University of New England Marine Animal Rescue Center
  • Northeast Stranding Network Members
  • SeaWorld
  • The Center for Infection and Immunity at Columbia University's Mailman School of Public Health
  • EcoHealth Alliance
  • Connecticut Veterinary Diagnostic Lab
  • Center for Disease Control
  • Massachusetts
  • Maine
  • New Hampshire

Q&As on the Subtype of Influenza A Virus Found in Five Harbor Seals Tested in Northeast Unusual Mortality Event

Q: What is the Influenza A virus?

A: There are three types of influenza viruses: A, B and C. Human influenza A and B viruses cause seasonal epidemics of disease almost every winter in the United States. Influenza type C infections cause a mild respiratory illness and are not thought to cause epidemics. 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 can be species specific, so not all subtypes are found in all species. For more information, visit the CDC website.

Q: What subtype of influenza A virus did you find?

A: The five seals initially collected by the New England Aquarium tested positive for the Influenza A H3N8 virus at two independent laboratories. An influenza subtype can be further broken down into lineages that represent the molecular structure of the virus. Although the H3N8 subtype encompasses the virus responsible for canine and equine influenza, this seal virus is molecularly different from those viruses and appears more similar to wild bird influenzas and falls into a different lineage. The H3N8 virus was previously detected in a by-caught harp seal (Phoca groenlandica) (see Bogomolni et al. 2008), although it appears to be molecularly different than this virus.

Q: What is canine influenza virus (dog flu)?

A: This is a contagious respiratory disease that originated with H3N8 infecting horses and then spread to dogs. Although the same subtype of virus, the seal virus is different than either the equine or the canine flu viruses.

Q. What is the risk to humans from this virus?

A. To date, there has not been a single reported case of human infection with the seal H3N8. However, human infections with new influenza viruses would be concerning if they occurred. Influenza viruses are constantly changing and it is possible for a virus to change so that it could infect humans and spread easily between humans. For this reason, the Centers for Disease Control, the National Wildlife Health Center and other organizations are investigating the H3N8 influenza virus related to this event and other animal influenza viruses very closely. More information on the CDC's influenza program can be found on the CDC website.

Q: What are the symptoms?

A: In the case of the five seals that tested positive for this virus, they all had pneumonia, lesions on the skin, and presumptive secondary bacterial infections. More information on general flu symptoms is available on the CDC website.

Q: How long has this influenza virus been around?

A: We currently don't know when this virus was introduced into this population and will be evaluating stored tissues to determine if this virus was present prior to the current infections. Those studies are underway. Additional studies of influenza in marine mammals along the west coast of the US and Canada have not resulted in detection of this virus subtype.

Q: Has influenza virus ever been detected in seals in the northeastern US before?

A: Yes, influenza has been detected in seals in New England

  • 1979-1980 harbor seal mortality event in the NE USA: H7N7
  • 1982-1983 harbor seal mortality event in the NE USA: H4N5
  • 1991- 1992: Influenza A viruses isolated from seals that died of pneumonia in Cape Cod, MA - H4N6 isolated from lung of 2 seal; H3N3 isolated from lung of three seals. The H3N3 strain identified here was more closely related to one that infects birds than any other species (see Callan et al. 1995).

Q: How does the virus spread among seals?

A: In most species, influenza virus can be spread within a species by direct contact with aerosolized respiratory secretions from infected individuals, by contact with contaminated objects, or can sometimes be transmitted between different species. It is not clear how this particular virus is transmitted among seals and whether there is any connection with circulating infections in wild birds or other species in the area.

Q. Is there anything you can do to protect the seals?

A. One of the challenges of wildlife management is managing large, healthy populations, and harbor seals in this region are one such group of wildlife. As is the case in many deer populations, diseases can spread quickly within large, dense populations. Typically, the best course of action is to let nature run its course in wild, free ranging robust animal populations. We are working to reduce the potential spread of the disease in rehabilitation centers and to reduce exposure for employees. The public can also help by keeping themselves and pets far away from seals in the wild.

Q: Did Influenza A H3N8 cause the Unusual Mortality Event?

A: It is too soon to tell if H3N8 is responsible for the overall Unusual Mortality Event.We will need to conduct additional testing on more samples and analyze other environmental and external data before a determination can be made about what may have caused this Unusual Mortality Event. These tests may take several months, even years to complete. It is important to note that since some of the animals were badly decomposed additional testing will not be possible on samples from these animals, which may further complicate the investigation into what caused this event.

Q: What else did you learn from testing these five seals?

A: Test results for twelve other viral pathogens and biotoxins were negative. In addition to influenza, some seals had bacterial infections which may be secondary to the influenza and further evaluations are being conducted. At this point these results are only indicative of the five cases, and additional evaluations are underway to determine whether the influenza A H3N8 virus has played a role in the overall mortalities.

Q: What should I do to protect myself and my pets against this virus?

A: 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 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 50 yards (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 1-866-755-NOAA (6622), or a local marine mammal stranding network member or visit NOAA's Northeast Region website for local contact information if animal has been on the beach for several days or appears to be in distress.

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

A: 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 will be distributing an infectious disease prevention fact sheet to our network responders. We have already provided the Network with the option to be involved in the Centers for Disease Control occupational risk assessment.

Q: Does eating seafood pose a risk?

A: Influenza A virus does not cause disease in fish so there is no risk of catching this virus by eating fish.

Q: Are there any risks to pets?

A: Pets should also be kept away from marine mammals. Dogs and cats also share infectious diseases with marine mammals and therefore should not be allowed to approach live or dead marine mammals or to consume dead marine mammals or their parts. NOAA Fisheries recommends contacting your pet's veterinarian to discuss the potential risk to pets in your local area. More information on canine flu can be found on the CDC website.

Q: How many Unusual Mortality Events have previously occurred in the Northeast?

A: To date, 60 Unusual Mortality Events have been formally declared in U.S. waters since 1991 (including the current Unusual Mortality Event), and 11 of these Unusual Mortality Events have occurred in the Northeast (6 involved cetaceans, 4 were specific to seals only, and 1 involved both taxa).

Q: What are the causes of previous Unusual Mortality Events in the Northeast and what is the cause of the current Unusual Mortality Event?

A: There have been 11 previous Unusual Mortality Events in the Northeast, 2 have been attributed to infectious diseases and 8 cases have unknown causes.

The investigation into the current Unusual Mortality Event is ongoing and no definitive cause has yet been identified for the increase in harbor seal mortalities in this area over the past two months.

Q: Was Influenza A H3N8 a factor in any of these previous events?

A: The influenza A virus has been linked to at least three seal dieoffs in the late 1970s, early 1980s, and early 1990s. During the winter of 1979 to 1980, an H7N7 influenza virus was associated with a severe outbreak of pneumonia in the New England harbor seal population (see related article). To our knowledge, H3N8 has only been detected in seals once before – in a by-caught harp seal (see Bogomolni et al. 2008 [pdf]).

Q: How are the sea bird, bluefin tuna and pilot whale strandings related to the seal deaths?

A: It is not unusual for strandings of other marine species to occur along our shore. At this point, NOAA Fisheries does not have any evidence to suggest that these strandings are related to the seal mortalities, but strandings of other marine species will be examined by collaborating partners and evaluated under the investigation. Of particular concern is determining whether wild birds in the area are infected.

Q: Are you collecting samples to compare from these other animals?

A: Collection and sampling of these animals falls under the purview of state agencies and local communities. Where possible, NOAA Fisheries is coordinating efforts to get a better understanding of what might have caused these deaths and see if there is any relationship to the seal mortalities.

Q: How do the harbor seal mortalities here in New England relate to the recent mortalities of ringed seals in Alaska?

A: At this point we have not determined that there is any relationship between these events. However an assisting pathologist is looking at samples from Alaska to see if a relationship does exist. It is not unusual for some level of natural mortality to occur in robust seal populations. However NOAA Fisheries intends to stay in close contact with our international stranding network contacts to monitor if anything out of the ordinary is occurring in other locations as well.

Q: Where can I find additional information on harbor seals?

A: More information on harbor seals is available on our website. You can also find seal viewing guidelines [pdf] on the Northeast regional office website.

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

A: To report violations or for more information on NOAA's Office of Law Enforcement call the toll-free number: 1-800-853-1964.

Q&A on Declaration of UME for Harbor Seal Mortalities in New England

Q: What is an Unusual Mortality Event (UME)?

A: An Unusual Mortality Event (UME) is defined under the Marine Mammal Protection Act as a stranding 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, then an official UME is declared.

Q: What criteria have been met?

A: The Working Group concluded that at least four of the seven criteria established for designation of a UME have been met. These mortalities are unusual because:

  • There is a marked increase in the magnitude or a marked change in the nature of morbidity, mortality or strandings when compared with prior records (criterion #1);
  • There is temporal change in morbidity, mortality or strandings is occurring (criterion #2);
  • There is a spatial change in morbidity, mortality or strandings is occurring (criterion #3);
  • Affected animals exhibit similar or unusual pathologic findings, behavior patterns, clinical signs, or general physical condition (e.g., blubber thickness) (criterion #5).

Q: What is the extent of the area where animals are stranding?

A : These strandings have been concentrated between Cape Elizabeth Maine and Cape Ann (northern Massachusetts). In the past few weeks, we have had additional strandings reported south of Boston in Cohasset and Scituate, Massachusetts.

Q: What are the next steps in the investigation now that a UME has been declared?

A: As part of the UME investigation process, an independent team of scientists is being assembled to coordinate with the Working Group to review the data collected and to determine potential next steps.

Q: Will you be collecting additional biological and environmental information?

A: The investigation team will continue to evaluate and analyze samples as needed to evaluate the situation. The decision on whether additional information is needed will be made by the UME Working Group.

Q: When will you have some results to share?

A: The investigative team is taking a tiered approach relying on pathology and epidemiology to guide the direction additional analyses may need to go as we rule in or out physical, chemical or biological factors that may be contributing to or causing these mortalities.

The initial evaluations are underway and further evaluations will continue over the next several months as new animals are found or new evidence determines the direction of the investigation. These rigorous investigations may take several more months, if not years, to complete. However, NOAA will make every effort to make these data available to the public as soon as it is legally and scientifically appropriate and possible.

Q: How many UMEs have previously occurred in the Northeast?

A: To date, 60 UMEs have been formally declared in U.S. waters since 1991 (including the current UME), and 11 of these UMEs have occurred in the Northeast (6 involved cetaceans, 4 were specific to seals only, and 1 involved both cetaceans and pinnipeds).

Q: What are the causes of previous UMEs in the Northeast and what is the cause of the current UME?

A: There have been 10 previous UMEs in the Northeast: 2 cases have been attributed to infectious diseases and 8 cases have unknown causes.

The investigation into the current UME is ongoing and no definitive cause has yet been identified for the increase in harbor seal mortalities in this area over the past two months.

Q: Where can I find additional information on harbor seals?

A: More information on harbor seals is available on our website.

Q: What should I do if I encounter a seal on the beach?

A: 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 from these animals so as not to disturb the animal, which may be just resting on the beach, and to avoid injury to themselves or their pets. While seals look cute, they are wild animals and can transmit disease. Some safe viewing tips:

  • Stay at least 50 yards (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 Service's stranding hotline at 1-866-755-NOAA (6622), or a local marine mammal stranding network member or visit NOAA's Northeast Region website for local contact information.

Seal viewing guidelines [pdf] can also be found on the Northeast Region's website.

Q: What should I do if I see a person or animal harassing a seal?

A: Call NOAA's Office of Law Enforcement at 1-800-853-1964.

Updated: March 27, 2013

NOAA logo Department of Commerce logo