FAQs about Marine Mammal Strandings

Killer Whale (A73) Rescue Team Photo: Lynne Barre, NOAA

1. How many marine mammal strandings occur?
2. How useful are marine mammal rehabilitation efforts?
3. How can NMFS support the marine mammal rehabilitation network to rescue injured or ill animals, while recommending that commercial fishermen shoot nuisance marine mammals?
4. Does rehabilitation contribute to the pinniped problem on the West Coast?
5. What information is gained from necropsies of stranded marine mammals?
6. In the past, how many strandings or deaths have occurred as a result of commercial fishermen shooting animals to protect gear/catch?
7. Why do marine mammals strand?
8. What is the status of the marine mammal rehabilitation facility guidelines?
9. What is the status of the marine mammal release criteria?
10. What is the scope of the Marine Mammal Health and Stranding Response Program?
11. What is the budget for the Marine Mammal Health and Stranding Response Program?
12. What are the costs of marine mammal rehabilitation?
13. What progress has been made in the contaminants component of the MMHSRP?
14. What are PCBs and DDTs?
15. Has the response to marine mammal unusual mortality events improved?
16. Do stranding networks have the authority to respond to "out of habitat" animals?
17. What happened with the harbor porpoise strandings on the East Coast in 1999?
18. Are there similar pinniped predation and fisheries interaction problems on the East Coast, and what is the NMFS position on lethal removal of East Coast pinnipeds?
19. How many marine mammal rehabilitation facilities are there in the United States?

1. How many marine mammal strandings occur?
   Stranding reporting and response efforts have increased significantly over the last three decades. Therefore, trends in stranding numbers are difficult to interpret. Since 1994, effort has been more consistent, therefore increasing our ability to actually interpret stranding rates. In the five years from 1994 through 1998, a total of 19,130 strandings were reported - an average of 3,826 per year. In 1998, a record number of strandings were reported (5,708), but the total was inflated by the number of pinnipeds stranding due to El Niño. In the Southwest Region alone in 1998, there were 3,568 pinniped strandings. The stranding composition varies by Region with the Southwest always having the highest number of pinniped strandings and the Southeast always having the highest number of cetacean strandings. Over the five year period (1994-1998), the totals by Region were:
   • Southeast Region- 3,683 cetaceans and 44 pinnipeds
   • Northeast Region- 1,013 cetaceans and 1,768 pinnipeds
   • Southwest Region- 624 cetaceans and 10,147 pinnipeds
   • Northwest Region- 119 cetaceans and 1,098 pinnipeds
   • Alaska Region- 462 cetaceans and 172 pinnipeds
   • FIVE YEAR TOTALS- 5,901 cetaceans and 13,229 pinnipeds
   
   
   
2. How useful are marine mammal rehabilitation efforts?
   In a biological sense, most rehabilitation efforts are not significant at a population level. The majority of marine mammals that are successfully rehabilitated are extremely small in proportion to total populations and are generally harbor seals or California sea lions from populations that are already healthy.
   
   Even though rehabilitation may not have significant conservation value on a population basis, rehabilitation centers: 1) have made a significant contribution to our understanding of diseases affecting marine mammals and treatment methods, 2) may help with critically endangered animals faced with catastrophic events (such as a harmful algal bloom), and 3) perform a humane function.
   
   NMFS recognizes that society places value on rehabilitation efforts. NMFS is a management agency, and our primary focus is on biological issues affecting populations in the wild.
   
   
3. How can NMFS support the marine mammal rehabilitation network to rescue injured or ill animals, while recommending that commercial fishermen shoot nuisance marine mammals?
   Both the rehabilitation community and NMFS are concerned about the health of pinniped populations and the health of marine ecosystems. The recommendations in the recent report to Congress include the selective lethal removal of certain seals or sea lions that may be inhibiting salmonid recovery or threatening human safety.
   
   The Marine Mammal Protection Act (MMPA) recognizes the benefits of pinnipeds as well as the health and stability of the ecosystem. These beliefs are maintained in the recommendations (including achieving optimum sustainable populations of Pacific harbor seals and California sea lions) and provide due consideration to declining salmonid populations that have been listed under the Endangered Species Act (ESA). The recommendations are constructed to apply only to very specific situations and would not result in indiscriminate killing of pinnipeds.
   
   Further, the use of non-lethal measures to deter pinnipeds is an integral part of the recommendations. Only in circumstances where individual seals or sea lions are affecting the recovery of ESA listed salmonids, subject to ongoing conservation and recovery efforts, do we recommend authorization for Federal or state resource agencies to lethally remove individual seals or sea lions. The use of safe, effective non-lethal deterrents measures needs further development because measures used to deter pinnipeds, such California sea lions from the Ballard Locks, have so far proven to be ineffective. Currently no data suggests that rehabilitated animals are becoming nuisance animals. In order to address this issue, increased post-release monitoring of rehabilitated seals or sea lions is needed. To date, this has been a largely unfunded component of the stranding network.
   
   
4. Does rehabilitation contribute to the pinniped problem on the West Coast?
   Just as the numbers of rehabilitated pinnipeds do not significantly contribute to species conservation, the numbers of rehabilitated pinnipeds should not significantly affect any problems being caused by the numbers of pinnipeds. NMFS would be the first to acknowledge that there is a potential for some rehabilitated animals to become nuisance animals if they become habituated to humans, but with a couple of individual animal exceptions, there are no data which indicate that this is happening. Both, marine mammal rehabilitators and NMFS recognize the need to determine if rehabilitation efforts are exacerbating human/pinniped conflicts. NMFS is encouraging facilities to increase the post-release monitoring of animals to determine both survival and whether the animal integrates into the normal population.
   
   
5. What information is gained from necropsies of stranded marine mammals?
   If a stranded marine mammal has recently died, then a significant amount of valuable information can be gained from it. For instance complete pathology to investigate diseases and parasites can be performed on these animals. In addition, dead animals provide the opportunity to collect and validate reproductive biology data, life history (what does the animal eat; how long do they live; how many calves do they have; how old are they when they first reproduce), pollution, and normal biology and physiology parameters. These types of sampling opportunities also provide validation and increased understanding and interpretation of data collected from wild populations. Through necropsies we have learned a significant amount about the basic physiology and biology of animals that are not accessible in the wild or through any other means. Finally necropsies have provided data on the incidence of human interactions including ship strikes, entanglements, hooks, and marine debris ingestions. These data help NMFS to make better management decisions about these stocks of marine mammals.
   
   
6. In the past, how many strandings or deaths have occurred as a result of commercial fishermen shooting animals to protect gear/catch?
   Gunshot injuries are the most common man-made cause of strandings in sea lions and seals on the West Coast. For example, from January 1986 to September 1998, 6,196 pinnipeds stranded alive on the Central California coast. Of these animals, 464 (7.5%) showed evidence of human interactions, in which 306 were gunshots. The majority of gunshot injuries were in young California sea lions.
   
   Although there seems to be no significant differences in gunshot incidences over the years, peak years were 1992 and 1998, both El Niño years. This is likely because depleted fish stocks drive young pinnipeds to seek out commercial fishing activities as a source of food. It is typically not possible to identify who shot these animals, although this connection with El Niño years suggests that these injuries may be as a result of interacting with commercial fishers.
   
   The effort to detect gunshot and other man-made injuries in stranded marine mammals has increased over the last decade, making it difficult to determine true increases in injuries versus increases in effort. The detection effort is well established now, and future trends will be easier to identify. NMFS will continue to work closely with stranding facilities to improve detection and documentation of man-made injuries in marine mammals.
   
   
7. Why do marine mammals strand?
   Although there are numerous reasons why marine mammals strand, there are typically two types of stranding events - mass strandings and single strandings. In most stranding cases, the cause of stranding is unknown, but some identified causes have included disease, parasite infestation, harmful algal blooms, injuries due to ship strikes or fishery entanglements, pollution exposure, trauma, and starvation. In addition, strandings often occur after unusual weather or oceanographic events. In the past few years, increased efforts in examining carcasses and live stranded animals has increased our knowledge of mortality rates and causes, allowing us to better understand population threats and pressures.
   
   
8. What is the status of the marine mammal rehabilitation facility guidelines?
   NMFS recognizes the need for rehabilitation facilities standards and, in July 1998, hosted a workshop to bring stranding network participants together to discuss possible criteria and facilities standards for marine mammal rehabilitation. The USDA's Animal and Plant Health Inspection Service shares NMFS' belief that rehabilitation facility guidelines are needed, and in August of 1998, NMFS initiated discussions with them to clarify jurisdiction over rehabilitation facilities and the need for rehabilitation facility guidelines. In February, 1999, NMFS reached an agreement with APHIS that NMFS will publish rehabilitation facilities guidelines and will monitor facility standards.
   
   Since NMFS will oversee these facilities APHIS will not inspect them unless requested by NMFS. The guidelines will better define public access and kinds of compensation for marine mammal rehabilitation facilities, will provide greater oversight (including inspections), and will include APHIS care and maintenance standards.
   
   As was pointed out at July 1998 workshop, the vast majority of rehabilitation facilities are already operating within the realm of good animal husbandry and care standards. This reflects the intent of the guidelines not to dramatically impact facilities, but to "raise the bar" for facility standards so that stranding centers can reasonably comply with them, while improving overall animal care.
   
   
9. What is the status of the marine mammal release criteria?
   For over seven years, NMFS, FWS, and numerous other institutions, individuals, and facilities have worked together to draft release criteria for marine mammals that have been rehabilitated at a stranding center. Under the MMPA, these guidelines were to be completed by the end of 1994. Although there are basic guidelines that NMFS and stranding network participants follow in determining the releasability of an animal, the document in preparation outlines comprehensive criteria and guidance. Because of its level of detail, it has undergone many iterations, with quickly developing fields of study and methodologies constantly changing the scope and content of the document. The last draft version went out for 60-day public comment period in May-June, 1998.
   
   As a result, over 300 pages of comments were received, which for the most part were substantial. NMFS is currently prioritizing and categorizing these comments and other document content needs for a small group of advisors to incorporate and to restructure document where needed. Further, NMFS is negotiating a contract with a rehabilitation veterinarian to work with the advisory group to finalize document. It is expected that the release criteria will be out for public comment by fall 2000.
   
   
10. What is the scope of the Marine Mammal Health and Stranding Response Program?
    Marine mammal stranding networks in the United States make up one facet of a broader, more comprehensive program called the Marine Mammal Health and Stranding Response Program (MMHSRP), established in the late 1980s in response to growing concern about marine mammals washing ashore in U.S. waters. The MMHSRP goals are: to facilitate collection and dissemination of data, to assess health trends in marine mammals, to correlate health with available data on physical, chemical, environmental, and biological parameters, and to coordinate effective responses to unusual mortality events.
    
    This program was formalized by the 1992 Amendments to the Marine Mammal Protection Act, and the National Marine Fisheries Service (NMFS) was designated as the lead agency to coordinate related activities. The program has the following components: stranding networks, responses/investigations of mortality events, biomonitoring, tissue/serum banking and analytical quality assurance.
    
    Stranding networks
    To respond to marine mammal strandings, volunteer stranding networks were established in all coastal states and are authorized through Letters of Authority from the NMFS regional offices. Through a National Coordinator and five regional coordinators, NMFS oversees, coordinates, and authorizes these activities and provides training to personnel.
    
    Biomonitoring
    In recent years, high concentrations of potentially toxic substances in marine mammals and an increase in new diseases have been documented, and scientists have begun to consider the possibility of a link between these toxic substances and marine mammal mortality events. These studies contribute to a growing, worldwide effort of marine mammal biomonitoring not only to help assess the health and contaminant loads of marine mammals, but also to assist in determining anthropogenic impacts on marine mammals, marine food chains and marine ecosystem health. NMFS provides participants in the program with training and some financial support. Using strandings, and bycatch animals, the participants provide tissue/serum archiving, samples for analyses, disease monitoring and reporting and additional response during disease investigations.
    
    The Analytical Quality Assurance (AQA)
    This aspect of the MMHSRP was designed to ensure accuracy, precision, level of detection, and intercomparability of data in the chemical analyses of marine mammal tissue samples. The AQA consists of annual interlaboratory comparisons and the development of control materials and standard reference materials for marine mammal tissues. The new NIST Charleston facility is taking the lead for this activity.
    
    Response to Unusual Mortality Events
    In response to the 1987-88 dolphin die-off, NMFS established a Working Group on Marine Mammal Unusual Mortality Events to create criteria for determining when an unusual mortality event is occurring and then to direct responses to such events. The Working Group is periodically called upon to lend its expertise in situations where circumstances indicate an unusual mortality event may be occurring and may provide guidance throughout the event. This Group meets annually, and at the last meeting discussed many issues including recent mortality events involving endangered species both in the United States and abroad. Through consultation with other government agencies, the Working Group has been able to build on its existing knowledge of mortality events to better respond to marine mammal unusual mortality event.
    
    National Marine Mammal Tissue Bank
    The National Marine Mammal Tissue Bank was formally established in 1992 and provides protocols and techniques for the long-term storage of tissues from marine mammals for retrospective contaminant analyses. The Tissue Bank is currently expanding at the Ft Johnson NOAA facility in Charleston, South Carolina. The Tissue Bank uses the biomonitoring sites noted above and other trained personnel to collect tissues on specific indicator species (Atlantic bottlenose dolphins, Atlantic white sided dolphins, pilot whales, harbor porpoise), mass stranding animals, and mortality events. In addition, a serum bank and long-term storage of histopathology tissues are being developed.
    
    
11. What is the budget for the Marine Mammal Health and Stranding Response Program?
    The MMHSRP was established in 1992 and initial funding focused on contaminant analyses and tissue banking. Over the last 5 years funding has increased to include disease and health related issues and stranding network training.
    
    The stranding network receives $50K per year with each NMFS regional network receiving $10K. The money is used for regional supplies, responses, analyses, training and education or outreach. In addition, there has been additional small amounts of money ($10-20K per year) available for large whale response with the focus being on right whales as a priority. Each region has a Regional Coordinator (either full time or only 10% time NMFS employee) and may allocate a small amount of money for regional responses also. Finally, meetings and workshops are held for additional training to the network, and these vary in numbers from year to year (1998 had two workshops totaling $50K).
    
    Unusual mortality response contingency fund never received funds from 1992 to 1999. This has hampered the responses and increased the burden to the stranding network and to other NMFS programs. When an event has happened in the past, funding has been taken from ongoing research programs. Funding needs have varied from $15,000 to $300,000.
    
    Contaminant monitoring and research has continued from 1991 to 1999 with funding being at higher levels in the early 1990s and at lower levels in the last three years. In addition, personnel working on the program have also decreased in headquarters.
    
    The National Marine Mammal Tissue Bank has maintained funding from both NMFS and U. S. Geologic Survey (DOI)(for Alaskan animals). Although the costs have increased, the funding has remained static.
    
    The 1998 budget* included:
    
    • Contaminant program and tissue bank - $376K
    • Disease/health program - $80K
    • Stranding networks and issues - $120K
    • Travel for collections/responses/investigations/annual meetings - $42K
    • Unusual mortality event - $15K
    • TOTAL for 1998 - $633K
      * this does not include NMFS personnel costs
    
    
    
12. What are the costs of marine mammal rehabilitation?
    The costs of rehabilitation vary depending on the species, location, facility involved, injury or disease, age of animal and length of rehabilitation. For instance, the estimated costs to rehabilitate the gray whale were $1 million. The costs for a typical pinniped rehabilitation can vary from $400 per animal to $50K per animal. Cetacean rehabilitation is much less frequent but often more costly and may range from $50K to $120K per animal. Transport costs are often donated through collaborations and agreements with the Department of Defense or the Coast Guard.
    
    
13. What progress has been made in the contaminants component of the MMHSRP?
    The contaminants component of the MMHSRP includes a biomonitoring, research, methods development, archival and quality assurance. The program has developed new methodologies to screen tissues for pollutants and has evaluated tissue residue levels in over 669 animals to establish baselines and evaluate trends in pollution exposures. Research has focused on projects evaluating pollutant effects on marine mammals, understanding pollutant exposure pathways through the food chain, understanding the kinetics of pollutants in marine mammal tissues, and evaluating stock differences in marine mammal species. Recent projects have included the evaluation of immune function in Northern fur seals in relation to pollutant levels, the correlation of tumors in California sea lions with pollutant levels, stock differentiation in Alaskan belugas based on pollutant types, and differentiation on feeding strategy and pollutant levels in killer whales. In addition to these activities, the National Marine Analytical Quality Assurance Program has been established as a cooperative program with the National Institute of Standards and Technology and has instituted annual interlaboratory comparisons between participating labs which are evaluating pollutants in marine mammals. These interlaboratory comparisons include national and international labs to increase the comparability and consistency of analyses. Finally, the National Marine Mammal Tissue Bank as part of the NIST Environmental Specimen Bank is continuing to collect tissues under strict protocols for archival for future retrospective studies and investigations. The samples are collected from indicator species through strandings, subsistence hunts, and fishery by-catch. The National Marine Mammal Tissue Bank is supported financially through NMFS, U.S. Geologic Survey and NIST. Future directions of the overall contaminants component include further evaluation of pollutant effects, continued method development, evaluation of food web sources of contaminants, trends in levels, expanded quality assurance program and expansion of the banking program to include blood banking.
    
    
14. What are PCBs and DDTs?
    PCB (polychlorinated biphenyl), a class of man-made chemical with world-wide industrial applications, and DDT (dichlorodiphyenyltrichloroethane), a pesticide, are both considered persistent organic pollutants and both have been banned in the U.S. for their harmful effects in wildlife and humans Even though these compounds have been banned for decades in the U.S., the levels of these compounds are still high in marine mammals sampled along our coasts. Both compounds are long lasting, reside in fat tissues (particularly in the blubber of marine mammals), and can be toxic causing such effects as reproductive impairment and immunosuppression. The actual impacts these compounds have on marine mammals is still unknown, but similar levels in other mammals has shown impacts on health, survival and reproductive function. The United Nations Environment Program is leading international negotiations to ban 12 persistent organic pollutants including DDT and PCB.
    
    
15. Has the response to marine mammal unusual mortality events improved?
    NMFS and the U.S. Fish and Wildlife Service have both benefited from the structure set up by the Marine Mammal Health and Stranding Response Act. With the preparation of the National Contingency Plan and the advice of the Working Group on Marine Mammal Unusual Mortality Events, our response to unusual mortality events is a real success story. We have been able to determine a variety of causes for unusual mortality events ranging from diseases such as morbilliviruses, to harmful algal blooms that produce biotoxins, to environmental conditions such as El Niño. Back in 1987-88, it was assumed that such events were relatively rare. With increasing sophistication, we have found that such events are not nearly as rare as had been assumed. Since the Working Group on Marine Mammal Unusual Mortality Events was set up in 1993, they have been consulted ten different times. Last month they were consulted on the increase in harbor porpoise deaths on the east coast. That consultation demonstrates how far we have come. Using information that had already been generated by the stranding network when NMFS detected an increase in stranding rates, the Working Group determined that the deaths did not meet the criteria for a mortality event because there was a multiplicity of causes including emaciated juveniles, human interactions, and interspecific aggression. In other words, a preliminary investigation had been well underway before the consultation occurred.
    
    List of Consultations
    1993- Harbor seals, Steller sea lions, and California sea lions on the central Washington coast-Determined to be human interaction
    1993-94- Bottlenose dolphins in the Gulf of Mexico-morbillivirus
    1994- Common dolphins in California-cause not determined
    1996- Right whales off Florida Georgia coast-evidence of human interactions
    1996- Manatees on west coast of Florida-brevetoxin
    1996- Bottlenose dolphins in Mississippi-cause not determined
    1997- Harbor seals in California-Unknown infectious respiratory disease
    1997- Pinnipeds on Pacific coast-El Niño
    1998- California sea lions in central California-harmful algal bloom, domoic acid
    1999- Harbor porpoise on the east coast, determined not to meet criteria for event because of multiplicity of causes
    
    
16. Do stranding networks have the authority to respond to "out of habitat" animals?
    Occasionally, marine mammals are found out of their normal range of habitat. An "out of habitat" animal can be on that is found in an area that is too warm or cold for that particular species, an offshore species of animal in coastal waters, or a strictly marine animal in a freshwater area. For example, dolphins that live only in the ocean may swim up a freshwater river for extended periods of time. An animal in this situation may not be in immediate need of assistance, but after a while can suffer negative effects of its unnatural surroundings, such as not being able to locate appropriate prey items. In many cases, these out of habitat animals will return to known areas of distribution on their own accord, with no ill effects and no need for intervention. However, the presence of "unusual" animals in a particular location may draw public attention, and as a result, stranding networks participants are often called to the scene to respond. In the past, stranding networks have been able to passively monitor the animal and assess its condition, and on rare occasions, stranding network participants have, through consultation with their Regional Stranding Coordinator, been authorized to capture the animal for reasons of medical treatment or relocation. This situations are handled on a case-by-case basis with the utmost regard for the health and safety of the stranding network participants, and with the resolve that there is no other alternative for the survival of the animal.
    
    
17. What happened with the harbor porpoise strandings on the East Coast in 1999?
    There was a marked increase in the number of stranded harbor porpoises along the East Coast. Since January 1999, there have been 216 strandings reported. The previous highs for harbor porpoise strandings on the East Coast were 103 in 1977, 91 in 1994, and 75 in 1997. The attached tables provide detail on the strandings by state. The increase in strandings was highest in Massachusetts in January - February and in the Mid-Atlantic (MD-NC) in March and April. The effort to detect and examine strandings was increased significantly this year in Massachusetts, but was stable or decreased in the Mid-Atlantic. Most of the porpoises which stranded in Massachusetts were sub_adults, many were emaciated., and none showed evidence of human interactions. In contrast, a significant portion of the animals which stranded in the Mid-Atlantic had indications of human interactions (fishery by-catch - mesh size or fishery not determined by animal examination). Excluding the porpoises from Massachusetts, of 55 animals fresh enough to make a determination, 33 showed evidence of human interactions.
    
    Excluding the human interactions noted above, gross necropsies did not found any consistent, remarkable findings other than that a majority of animals were immature and often emaciated. Three animals in Massachusetts and one animal in North Carolina had oral ulcers, one animal (NC) had pox lesions, one animal had hepatitis (MA), several had parasitic pneumonia, several had non-specific infections, and the majority showed evidence of atrophy of fat. Two animals from NC showed evidence of trauma induced by bottlenose dolphins. Tissues from these animals are being analyzed with PCR for morbillivirus, and initial results have all been negative.
    
    During the peak of the increase in the Mid-Atlantic, NMFS requested that the stranding network carefully examine all animals for evidence of human interactions and that when conditions of carcasses were appropriate, samples be collected for analyses. Unfortunately most of the carcasses were condition 3-5 and too decomposed to easily determine the cause of death. The decomposed carcasses have been frozen and will be examined by a team of experts in September 1999 at the Smithsonian Institute National Museum of Natural History. In addition, the NOAA Beaufort Lab is the environmental conditions this year as compared to recent years and to peak stranding years. The working group on Marine Mammal Unusual Mortality Events was consulted about the event and decided that although the stranding rate was high it did not warrant designation as an unusual mortality event because there appear to be multiple factors, the rates are decreasing now, and the total rate was temporally and spatially spread out.
    
    NMFS will examine all the data and analyses after the September necropsy session and will provide a report to the working group on the findings of this increased stranding rate in harbor porpoises.
    
    
18. Are there similar pinniped predation and fisheries interaction problems on the East Coast, and what is the NMFS position on lethal removal of East Coast pinnipeds?
    NMFS has not identified any fish stocks for which pinniped predation is a significant issue. Fisheries interactions also seem to be much less of an issue on the east coast. Although not well documented, pinniped predation can affect salmon aquaculture. Last year, NMFS submitted a report to the Congress on pinniped-salmon aquaculture interactions in the Gulf of Maine. That report pointed out that non-lethal methods of limiting pinniped predation had not been fully utilized. Although currently prohibited under the MMPA, the report did recommend that aquaculture operators be allowed to kill the rare pinniped that actually enters a net-pen.
    
    
19. How many marine mammal rehabilitation facilities are there in the United States?
    NMFS oversees marine mammal stranding response through a Regional Stranding Coordinator in each of the five NMFS regions. In all, there are over 400 organizations authorized by NMFS to respond to marine mammals strandings in some form or another. However, there are currently only 42 facilities that can rehabilitate stranded marine mammals under NMFS jurisdiction. In addition to these live stranding centers, there are many stranding network participants who are strictly beach or "first" responders (i.e., they rescue the animal, but don't have adequate facilities to rehabilitate marine mammals over a period of time). Further, there are even more network participants that respond solely to dead marine mammal strandings. Responders to dead strandings make up the vast majority of LOA holders and may include Federal, state, and local governmental entities; non-profit organizations, academic institutions, museums, scientists, and managers among others.