Review of the Marine Mammal Unusual Mortality Event 

Response Program of the National Marine Fisheries Service 

Frances M.D. Gulland, Vet. MB, MRCVS, Ph.D. 

 

U.S. Department of Commerce 

National Oceanic and Atmospheric Administration 

National Marine Fisheries Service 

NOAA Technical Memorandum NMFS-OPR-33 

September 2006
A copy of this report may be obtained from: 

National Oceanic and Atmospheric Administration 

National Marine Fisheries Service 

Office of Protected Resources 

1315 East-West Highway 

Silver Spring, Maryland 20910 

Or online at: 

www.nmfs.noaa.gov/pr/health/publications.htm 

This technical memorandum series is used for documentation and timely communication of 

preliminary results, interim reports, or similar special-purpose information. Although the 

memoranda are not subject to complete formal review, editorial control, or detailed editing, 

they are expected to reflect sound professional work. The views and conclusions expressed 

by the authors are not necessarily those of the National Marine Fisheries Service. In 

addition, the mention of trade names or commercial firms is for information only and does 

not imply endorsement by the National Marine Fisheries Service. 

Suggested citation: 

Gulland, F.M.D. 2006. Review of the Marine Mammal Unusual Mortality Event Response 

Program of the National Marine Fisheries Service. U.S. Dept. of Commerce, NOAA Tech. 

Memo. NMFS-OPR-33, 37 p. 
Review of the Marine Mammal Unusual Mortality Event 

Response Program of the National Marine Fisheries Service 

Frances M.D. Gulland, Vet. MB, MRCVS, Ph.D. 

NOAA/Marine Mammal Health and Stranding Response Program 

and 

The Marine Mammal Center 

The Marin Headlands 

1065 Fort Cronkhite 

Sausalito, California 94965 

NOAA Technical Memorandum NMFS-OPR-33 

September 2006 

U.S. Department of Commerce 

Carlos Gutierrez, Secretary 

National Oceanic and Atmospheric Administration 

Vice Admiral Conrad C. Lautenbacher, Jr. USN (Ret), 

Under Secretary for Oceans and Atmosphere 

National Marine Fisheries Service 

William T. Hogarth, Ph.D., Assistant Administrator for Fisheries 

TABLE OF CONTENTS 

 Page 

EXECUTIVE SUMMARY...................................................................................v 

INTRODUCTION.............................................................................................1 

 Why Investigate Marine Mammal Mortality......................................................1 

 Marine Mammal Mortality..........................................................................2 

 Agency Process for Responding to Marine Mammal Unusual Mortality Events............3 

ANALYSIS OF 27 YEARS OF MARINE MAMMAL UNUSUAL MORTALITY 

EVENTS, 1978-2005...........................................................................................4 

 Temporal and Spatial Trends in Mortality Events................................................5 

 Efforts to Improve Response......................................................................22 

CHALLENGES AND FUTURE DIRECTIONS........................................................23 

 Data Quality and Management....................................................................23 

 Administrative Process.............................................................................25 

 Response Logistics.................................................................................27 

 Impact on Population and Role of Environmental Parameters...............................28 

 

ACKNOWLEDGEMENTS................................................................................29 

REFERENCES...............................................................................................30 

iii
iv
EXECUTIVE SUMMARY 

Rising numbers of reports of diseases in marine organisms have raised concerns over 

deteriorating ocean health amongst scientists, politicians, managers and the public. These marine 

diseases and die-offs can alter marine populations and cause major changes in marine 

communities, and may impact human health. Furthermore, these die-offs often command 

considerable public and media interest. Whether or not this increase in reports represents a true 

general deterioration in health of marine mammals is unclear, as investigations of marine 

mammal health remain very limited. To date, the National Marine Fisheries Service (NMFS) has 

implemented a variety of approaches to improve responses to marine mammal Unusual Mortality 

Events (UMEs). These have been achieved with a limited budget and few staff, and have relied 

upon in-kind work and funding from stranding network participants and collaborating 

researchers. This document reviews the NMFS program to respond to marine mammal mortality 

events, and identify strategies to improve responses so that health trends and causes of disease 

can be determined, and effective timely responses that meet animal welfare and public outreach 

needs are mounted. 

Since 1978, 57 mortality events have been detected by the stranding network, of which 29 were 

declared UMEs. Despite significant efforts and financial resources directed at UME responses, 

the causes of many mortality events remain unknown, and the rate of diagnosis has not improved 

over the last 14 years since the UME program was established. Prior to establishing the UME 

response program in 1991, the etiologies of 10/11 (91 percent) mortality events were determined 

and reported. Since 1991, the etiologies of 26/46 (56 percent) mortality events and 14/29 (48 

percent) of UMEs have been identified. Thus it appears that establishing the UME process has 

not enhanced the identification of causes of mortality events. However, mortality events with 

identified causes are more likely to be documented in the peer reviewed literature, and thus 

identified retrospectively, than events with no identified causes. Thus, there may have been a 

number of marine mammal mortality events of unknown etiology between 1978 and 1991 that 

are not recorded here. Determinations of causes of mortalities have also been influenced by the 

development of assays; some assays used today were not available 5-10 years ago. 

Causes of mortality events have included biotoxins, viruses, bacteria, parasites, human 

interactions and oil spills, as well as changes in oceanographic conditions and detection rate of 

carcasses by humans. Prior to 1996, when a manatee UME was caused by brevetoxin, only 5 

marine mammal mortality events of 24 reported (20 percent) were associated with exposure to 

biotoxins. Since then, 12/31 (39 percent) of mortality events have been associated with exposure 

to biotoxins, and events caused by domoic acid and brevetoxin appear to be increasing in 

frequency. Interestingly, influenza virus was the cause of two mortality events in 1979 and 1982, 

but in more recent years, morbillivirus epidemics have been the more common causes of virusassociated mortality events. Some mortality events, such as those along the California coast 

associated with El Niño and leptospirosis, occur at regular intervals, and the decision as to 

whether or not to classify these as UMEs has varied among years. The factors predisposing 

marine mammals to mortality events and the impacts of such events on host population dynamics 

are unclear. 

v
To improve effective responses to marine mammal mortality events, the following actions are 

recommended: 

1. Expand the National stranding database to: include data on causes of death and disease 

investigations; integrate single stranding, mass stranding and UME data into one real 

time searchable database with a method for rapid identification of these “group” events; 

and develop data sharing protocols to facilitate collaborations and extensions of analyses. 

2. Improve the stranding network’s surveillance capabilities by: dedicating funding sources 

(e.g. Prescott program) to stranding network members to ensure a consistent level of 

response; holding regular training workshops for Letter of Authorization Holders 

including necropsy techniques, sample collection, archiving and shipping, chain of 

custody and evidence handling procedures, and disposal techniques for hazardous 

materials and carcasses; directing training and funding to areas of the network with poor 

coverage of the coastline and detection rates; developing protocols for regional stranding 

coordinators on event notification; stocking each region with supplies for emergency 

sampling of marine mammals and identifying appropriate storage facilities in each 

response area; posting response, sampling and shipping protocols to a website for easy 

access; and identifying funds for carcass handling and disposal so that large whales can 

be towed ashore for examination then disposal. 

3. Improve the administrative process involved in mounting mortality event investigations 

by maintaining a full time dedicated UME coordinator (Executive Secretary) to track the 

administrative process, develop effective intra-agency communication, facilitate 

communication between the Working Group and the field investigation team and act as 

an off-site coordinator. 

4. Establish emergency response teams of trained personnel with allocated time to be 

employed during responses to UMEs. These would include an on site coordinator, a 

pathologist, a research assistant and a data manager, from which would be drawn 

appropriate response teams for specific events, based on the existing abilities and needs 

of the local stranding networks. Availability of team members would be accommodated 

with a retainer and NMFS would pay for all travel associated with the response. 

5. Require timely submission of final reports and encourage peer reviewed publications on 

UME investigations by: requiring final reports to be submitted from UMEs as a condition 

of receiving funds; funding report writing by qualified personnel; fostering research 

collaborations through workshops and seminars 

6. Develop a centralized national sample archiving system to include fluids and tissues from 

animals during UME events. 

7. Improve the availability and quality of diagnostic tests performed on samples from 

marine mammals by: identifying and funding dedicated laboratories for pathology, 

infectious diseases, biotoxin and contaminant analyses; developing a quality assurance 

vi
program for laboratories analyzing marine mammal samples; and ensuring collection of 

suitable samples by establishing protocols for investigation of specific events that are 

known to occur, such as domoic acid toxicosis, brevetoxicosis, leptospirosis, beaked 

whale strandings, morbillivirus and influenza epidemics, and human interactions. 

8. Integrate the Marine Mammal Health and Stranding Response Program with stock 

assessment and population monitoring programs of the NMFS, U.S. Fish and Wildlife 

Service, and U.S. Geological Survey, as well as with other federal programs addressing 

environmental and climate parameters impacting marine mammal health (e.g.: the 

Ecology and Oceanography of Harmful Algal Blooms), to determine the impact of 

disease and changes in health on host population dynamics. 

9. Develop and fund a research plan addressing factors predisposing populations to 

mortality events.

vii
0 
INTRODUCTION 

Why Investigate Marine Mammal Mortality 

Rising numbers of reports of diseases in marine organisms have raised concerns over 

deteriorating ocean health amongst scientists, politicians, managers and the public (Epstein 1996, 

Harvell et al. 1999). These marine diseases and die-offs can alter populations and cause major 

changes in marine communities (Harvell et al. 2004, Kim et al. 2005). Furthermore, threats to 

ocean health can directly and indirectly impact human health (National Research Council 1999, 

Knap et al. 2002).Whether or not this increase in reports represents a true general degeneration in 

the health of marine life is unclear (Harvell et al. 1999, Lafferty et al. 2004, Ward and Lafferty 

2004). Also unclear is the impact of human activities on health of marine life. Morbidity and 

mortality of marine mammals have resulted from pathogens originating on land spreading to the 

ocean, as well as from harmful algal blooms and epidemics of virulent viruses and bacteria 

(Geraci et al. 1999). The role of anthropogenic factors and climate change in these die-offs is 

unknown. This lack of information on the true incidence of disease in marine life and its 

underlying causes is due to the lack of long term data on health of marine organisms (Harvell et 

al. 2002, Kim et al. 2005). Amongst marine organisms, marine mammals are hard to study due to 

their pelagic life styles, long generation time and large size. However, when marine mammals 

wash ashore sick or dying, they command considerable attention and concern. There is thus an 

interest from the public, as well as from scientists and managers, to determine the state of marine 

mammal health, and identify the anthropogenic influences on the health of these animals. 

The Marine Mammal Protection Act (MMPA), established in 1972, recognized the need for 

determining the cause of death or injury of marine mammals. The MMPA was amended in 1992 

to specifically establish of a Marine Mammal Health and Stranding Response Program 

(MMHSRP), with three purposes: 

1. Facilitate the collection and dissemination of reference data on the health of marine 

mammals and health trends of marine mammals in the wild; 

2. Correlate the health of marine mammals and marine mammal populations, in the wild, 

with available data on physical, chemical, and biological environmental parameters; and 

3. Coordinate effective responses to unusual mortality events by establishing a process in 

the Department of Commerce. 

Within the Department of Commerce, the National Marine Fisheries Service (NMFS) has 

developed a program to investigate marine mammal health, so as to understand the causes of 

marine mammal morbidity and mortality and their impacts on populations, as well as to 

minimize deaths of marine mammals and provide care for marine mammals during unusual 

mortality events (UMEs). Data from this program can be used to develop a baseline on marine 

mammal health from which changes in ocean health might be inferred. 

1
Marine Mammal Mortality 

There are four sources of information that can be used to detect changes in the frequency of 

disease and die-offs of marine mammals: decreases in population estimates during regular 

population censuses, changes in the prevalence of disease and other health parameters detected 

during handling of animals, changes in individual records of stranded animals, and increases in 

UMEs. Regular population monitoring can reveal declines in abundance suggesting increases in 

mortality occurred, but often carcasses are not found. For example, aerial counts and skiff 

surveys revealed a 70 percent decline in sea otters (Enhydra lutris) around the Aleutian Islands 

from 1992 to 2000 (Doroff et al. 2003). Similarly, demographic data on the western population 

of Steller sea lions (Eumatopias jubatus) indicate a 70 percent decline from the late 1970s 

through the 1980s associated with juvenile mortality (York 1994), and a further 40 percent 

decrease through the 1990s associated with increased adult mortality (Holmes and York 2003). 

The lack of carcasses associated with these declines may be a result of their consumption by 

predators or scavengers, decomposition at sea, or be a result of the lack of detection due to 

inaccessible or sparsely populated coastlines. Furthermore, although surveys detect population 

changes such as declines caused by mortality, the degree of change must be considerable before 

such a decline can be detected, so that significant declines are often not detected for years after 

their initial occurrence (Gerodette 1987). Strandings may thus help identify issues affecting 

marine mammal populations before surveys detect declines. For example, an increase in gray 

whale strandings was observed along the west coast of the U.S. and Mexico in 1999, but a 

decline in the population was not detected by survey effort until 2001 (Gulland et al. 2005). 

Directed health assessments of marine mammal populations can provide information on health 

parameters, incidence and prevalence of disease, and body condition, along with data on factors 

that may impact population health, such as environmental contaminants. For example, 

population health evaluation systems are being developed for bottlenose dolphins utilizing data 

and samples collected during capture, sample, mark, and release operations (Wells et al. 2004). 

These programs are allowing the evaluation of health and reproductive risks from environmental 

contaminants (Schwacke et al. 2002, Wells et al. 2005), and provide a mechanism for comparing 

risks across populations (Hansen et al. 2004). Population health assessments have the potential 

to identify health issues before they lead to increased morbidity and mortality, but logistics and 

expense often limit these kinds of efforts, and thus their coverage of the species’ range. 

An increase in numbers of strandings can indicate that an increase in marine mammal mortality 

is occurring, although stranding rates do not correlate directly with mortality rates due to a 

variety of factors influencing carcass deposition and detection on beaches (Eguchi 2002). A 

stranded animal is defined as “any dead marine mammal on a beach or floating near-shore; any 

live cetacean on a beach or in water so shallow that it is unable to free itself and resume normal 

activity; any live pinniped which is unable or unwilling to leave the shore because of injury or 

poor health” (Wilkinson 1991). Although some causes of strandings have been identified, the 

majority, especially those of cetaceans, remain enigmatic (Geraci 1978, Geraci et al. 1999). 

Documentation of stranding events has improved globally over the last 70 years, the earliest 

organized attempts originating in the United Kingdom. These records have allowed reviews of 

2
such occurrences (Fraser 1934, 1946, 1953, and 1956; Geraci 1978, Sergeant 1982, Dierauf and 

Gulland 2001). 

Strandings have been defined as single, mass or part of unusual mortality events. A mass 

stranding of cetaceans is an event in which two or more individuals of the same species, 

excluding a single cow-calf pair, beach within a given spatial and temporal reference (Wilkinson 

1991). Typically mass strandings involve a single species known to have strong social bonds 

although multi-species events also occur. A mass stranding event may span one or more days, 

and range over miles of shoreline bridging multiple counties, or sandbars and outlying islands. 

Despite the attention mass strandings receive from both the public and scientific community, 

they remain hard to manage as they are often logistically overwhelming, and the reasons for their 

occurrence remain hard to identify. UMEs are strandings of multiple animals under unusual 

circumstances, involving a significant die-off of marine mammals and demanding an immediate 

response. 

Agency Process for Responding to Marine Mammal UMEs 

In 1988, the dramatic phocine distemper epizootic that killed over 18,000 harbor seals (Phoca 

vitulina) in Europe raised awareness of the need for contingency plans to investigate marine 

mammal die-offs, and for long-term monitoring of strandings (Heide-Jorgensen et al. 1992, 

Thompson and Hall 1993). In 1989, the Department of the Environment in the United Kingdom 

established a national program to investigate marine mammal mortalities, and to coordinate 

responses. In the U.S., three specific events triggered the development of a legal framework that 

addressed marine mammal unusual mortality events. The first was a stranding of 14 humpback 

whales (Megaptera novaeangliae) off Cape Cod, Massachusetts in 1987 (Geraci et al. 1989). 

The second was a bottlenose dolphin (Tursiops truncatus) die-off along the Atlantic seaboard 

during 1987 and 1988 (Geraci, 1989), and the third was the Exxon Valdez oil spill in Prince 

William Sound, Alaska, in 1989 (Loughlin 1994). As a response to the increased concerns over 

these die-offs and potential for environmental degradation, the Marine Mammal Health and 

Stranding Response Act was established as Title IV of the MMPA. 

To determine when an unusual mortality event is occurring, and then to direct responses to such 

an event, a body of scientific experts called the Working Group on Marine Mammal Unusual 

Mortality Events (the Working Group), was developed in 1991 as an advisory board to the 

Secretary of Commerce and Secretary of the Interior. In 1992, the legislation (Title IV Section 

404) was codified to establish the group. The Working Group is now composed of 12 members 

from academia, conservation organizations, state and/or federal natural resource agencies who 

have expertise in marine mammal biology, toxicology, pathology, ecology and epidemiology, 

and marine conservation. Agencies represented at meetings of the Working Group include the 

NMFS, the U.S. Fish and Wildlife Service (USFWS), the Marine Mammal Commission, the U.S. 

Environmental Protection Agency, and the U.S. Department of Agriculture. Since 1999, in 

response to die-offs of species crossing the U.S. border (gray whales, harp seals and right 

whales) an international liason from Canada and another from Mexico have joined the WG. A 

staff person from NMFS serves as Executive Secretary of the Working Group, working for the 

Chair of the Working Group, the latter being elected by the Working Group members every two 

years from among its 12 members. Working Group member terms are three years, with no 

3
person being allowed to serve more than two consecutive terms. Every three years, a third of the 

Working Group members may rotate off, and new members are invited to join the Working 

Group. The charges of the Working Group, as mandated in Title IV, are to determine whether or 

not a UME is occurring, to determine, after a UME has begun, when response to that UME is no 

longer necessary, and to help develop a Contingency Plan for responding to and investigating 

marine mammal UMEs. The Working Group is not currently mandated to review reports on 

UMEs or to issue follow up advice, however NMFS has established that as policy for NMFS 

marine mammal species. 

Despite the establishment of a protocol and Working Group to advise on UME responses and 

investigations, funding for such activities was minimal until 2000. An emergency fund for UMEs 

was authorized under Title IV in 1992, but funds were not appropriated until 2005. In 2000, a 

small amount of MMHSRP research funds were used establish a cooperative agreement with the 

National Fish and Wildlife Foundation to reimburse stranding network members. In 2005, 

specific appropriations language enabled establishment of the formal fund within the U.S. 

Department of Treasury into which private donations can be accepted. 

There are four aims of a UME investigation: to minimize deaths, determine the cause of the 

event, determine the effect of the event on the population, and to identify the role of 

environmental parameters in the event. These investigations are logistically difficult, labor 

intensive and expensive. Preparation, training and detection of events have been difficult to 

maintain due to minimal funding. Efforts thus need to be focused to maximize the success of the 

program with the resources available. This report reviews the response of the MMHSRP to 

UMEs, and identifies areas for future investment to improve our understanding of marine 

mammal health and its impact on populations. 

ANALYSIS OF 27 YEARS OF MARINE MAMMAL UNUSUAL MORTALITY EVENTS, 

1978-2005 

Marine Mammal UMEs are detected by the stranding network members through their regular 

stranding response. This response effort varies temporally and spatially around the coast of the 

U.S. depending upon the topography of and access to the coastline, the density of human 

population, the weather, and the level of expertise of the personnel involved. The stranding 

network personnel are authorized by either NMFS or the USFWS to collect stranded marine 

mammals through Letters of Agreement (LOA), or are local, state or federal government 

employees operating under Section 109h of the MMPA. The locations of LOA holders 

authorized to respond to stranded marine mammals are shown in Figure 1. The training and 

financial resources available to LOA holders varies enormously, from individuals with an 

interest in marine mammals, to organizations with all the resources of a veterinary school. 

Stranding data collected by these LOA holders are used to detect UMEs, and the stranding 

network members are the key responders to the UME. When an increase in strandings or an 

unusual type of stranding occurs, the LOA holders contact NMFS or USFWS who consult with 

the Working Group to determine whether or not a UME is occurring using seven criteria. 

4
Although the criteria were established in 1991, the formal declaration of a mortality event as a 

UME by the NMFS was not routine until 1994. From 1991 to 2003, the criteria were: 

1. A marked increase in the magnitude of strandings when compared with prior records. 

2. Animals are stranding at a time of the year when strandings are unusual. 

3. An increase in strandings is occurring in a very localized area. 

4. The species, age, or sex composition of the affected animals is different than that of 

animals that normally strand in the area at that time of the year. 

5. Stranded animals exhibit similar and/or unusual pathologic findings, or the general 

physical condition of stranded animals is different from what is normally seen. 

6. Mortality is accompanied by behavior patterns observed among living individuals in the 

wild that are unusual, such occurrence in habitats normally avoided or abnormal patterns 

of swimming and diving. 

7. Critically endangered species are stranding. 

In 2004, these were modified by the Working Group to the following, but have not been formally 

adopted: 

1. A marked increase in the magnitude or a marked change in the nature of morbidity, 

mortality or strandings when compared with prior records. 

2. A temporal change in morbidity, mortality or strandings is occurring. 

3. A spatial change in morbidity, mortality or strandings is occurring. 

4. The species, age, or sex composition of the affected animals is different than that of animals 

that are normally affected. 

5. Affected animals exhibit similar or unusual pathologic findings, behavior patterns, clinical 

signs, or general physical condition (e.g. blubber thickness). 

6. Potentially significant morbidity, mortality or stranding is observed in species, stocks or 

populations that are particularly vulnerable (e.g. listed as depleted, threatened or endangered 

or declining). For example, stranding of three or four right whales may be cause for great 

concern whereas stranding of a similar number of fin whales may not. 

7. Morbidity is observed concurrent with or as part of an unexplained continual decline of a 

marine mammal population, stock, or species. 

If a mortality event is officially declared a UME, then the Contingency Fund can be used to 

finance response to the event. This response consists of care of live animals, response to dead 

animals, determining the cause of the event, its impact on the population, and the role of 

environmental variables in triggering the event. 

Temporal and Spatial Trends in Mortality Events 

From 1978 to the establishment of the Working Group in 1991, 11 die-offs were reported in U.S. 

waters. Since 1991, there have been 46 die-offs, of which 29 were formally declared UMEs 

(Table 1). These occurred in all regions of the stranding network (Figure 1), although most 

events and declared UMEs occurred in California and Florida. These are also areas with more 

LOA holders in the stranding network per state than other areas (Figure 1). California and 

Florida are also states with very accessible coastline and high human population density to detect 

5 
strandings. There were one to six mortality events a year, with no significant trend in the number 

of UMEs or mortality events per year (Figure 1). Bottlenose dolphins were the species most 

commonly impacted by UMEs, followed by California sea lions and Florida manatees (Figure 2), 

this species distribution corresponding to the spatial distribution of mortality events (Figure 1). 

Despite significant efforts and financial resources directed at UME responses, the causes of 

many mortality events remain unknown, and the rate of diagnosis has not improved over the last 

14 years. Prior to 1992, the etiologies of 10/11 (91 percent) mortality events were determined 

and reported in peer reviewed literature. Since 1992, the etiologies of 26/46 (56 percent) 

mortality events and 14/29 (48 percent) of UMEs have been identified (Table 1, Figures 3, 4, and 

5). It therefore appears that establishing the UME process has not enhanced the identification of 

causes of mortality events. However, mortality events with identified causes are more likely to 

be documented in the peer reviewed literature, and thus identified retrospectively than events 

with no identified causes. Thus there may have been a number of marine mammal mortality 

events of unknown etiology between 1978 and 1992 that are not recorded here. 

Causes of mortality events have included biotoxins, viruses, bacteria, parasites, human 

interactions and oil spills, and changes in oceanographic conditions and detection rate of 

carcasses by humans (Figure 3 and 5). Prior to 1996, when a manatee UME was caused by 

brevetoxin, only five mortality events (20 percent) were associated with exposure to biotoxins. 

Since then, 12/31 (39 percent) of mortality events have been associated with exposure to 

biotoxins. Events caused by domoic acid on the west coast of the U.S. and brevetoxin on the east 

coast appear to be increasing in frequency. Comparing the etiologies of mortality events before 

the UME process was established in 1992 to afterwards (Figure 5) the percentage of mortality 

events due to harmful algal blooms (HABs) has increased, although the determination of etiology 

of die-offs has not changed significantly. This may reflect an increase in the frequency of HABs 

around the U.S., although some of the diagnostic tests for detecting biotoxins have only recently 

become available. Interestingly, influenza virus was the cause of two mortality events in 1979 

and 1982, but in more recent years, morbillivirus epidemics have been the more common causes 

of virus-associated mortality events. Some mortality events, such as those along the California 

coast associated with El Niño and leptospirosis, occur at regular intervals, and the decision as to 

whether or not to for classify these as UMEs has varied among years. The factors predisposing 

marine mammals to mortality events and the impacts of such events on host population dynamics 

are unclear. 

6
Table 1. Summary of Mortality Events in the United States Reported by the Stranding Network 

between 1978 and 2005. 

Year Species and number 

affected 

Location Working Group 

consulted, 

Declared a UME,

Onsite 

coordinator 

appointed 

Cause and 

comments 

References 

1978 Hawaiian monk seal 

Monachus schauinslandi 

(50) 

North West 

Hawaiian 

Islands 

Not applicable Ciguatoxin and 

maitotoxin 

suspected 

Gilmartin et al. 1980 

1979-

1980 

Harbor seals 

Phoca vitulina 

(400) 

Cape Cod, 

Massachusetts 

Not applicable Influenza A 

A mycoplasma 

was concurrently 

isolated from 

these seals 

Geraci et al. 1982 

1982 Harbor seals 

Phoca vitulina

Cape Cod, 

Massachusetts 

Not applicable Influenza A Hinshaw et al. 1984 

1982 Florida manatees 

Trichechus manatus

latirostris

(39) 

Southwest 

Florida 

Not applicable Brevetoxin O’Shea et al. 1991 

1983 Several pinniped species 

(Hundreds) 

West coast of 

U.S. 

Not applicable El Nino Trillmich and Ono 1991 

1984 California sea lions 

Zalophus californianus 

(226) 

California Not applicable Leptospirosis Dierauf et al. 1985 

1987 Sea otters 

Enhydra lutris 

(34) 

Kodiak Island, 

Alaska 

Not applicable Saxitoxin DeGange and Vacca 1989 

1987 Humpback whales 

Megaptera novaeangliae 

(14) 

Massachusetts Not applicable Saxitoxin Geraci et al. 1989 

1987-

1988 

Bottlenose dolphins 

Tursiops truncatus 

(645) 

New Jersey 

Delaware 

Virginia 

North Carolina 

South Carolina 

Georgia 

Florida 

Not applicable Morbillivirus. 

Brevetoxin was 

detected in 

dolphins, its role 

in the event is 

unclear. 

Scott et al. 1988 

Geraci et al. 1989 

Lipscomb et al. 1994 

Duignan et al. 1996 

Schulman et al. 1997 

Friedlaender 2000 

McLellan et al. 2002 

1989 Sea otters 

Enhydra lutris

(3,500-5,000) 

Alaska Not applicable Exon Valdez oil 

spill 

Loughlin 1994 

1990 Bottlenose dolphins 

Tursiops truncatus 

(146) 

Texas 

Louisiana 

Mississippi 

Alabama 

Not applicable Unknown. 

Unusual skin 

lesions observed 

Memo B. Brown to N. Foster 

March 2 1990 

Kuehl and Haebler 1995 

Hansen 1992 

Medway report to Fox 

June 29 1990 

7
Year Species and number 

affected 

Location Working Group 

consulted, 

Declared a UME,

Onsite 

coordinator 

appointed 

Cause and 

comments 

References 

Formation of the Working Group on Marine Mammal Unusual Mortality Events 

1991 Harbor seals 

Phoca vitulina 

(34) 

New Jersey Yes, no, no (WG 

consulted. Formal 

criteria not in 

place). 

Unknown. 

Erysipelothrix 

rhusiopathiae

cultured from 4 

seals, poxvirus 

present in one, 

saxitoxin negative 

Informational Memo J.A. 

Knauss 

May 10 1991 

1991 California sea lions 

Zalophus californianus

(160) 

California Yes, no, no Leptospirosis Gulland et al. 1996 

1991 Bottlenose dolphins 

Tursiops truncatus 

(30) 

(Sarasota) 

Florida 

Yes, yes, medical 

director requested 

Unknown 

1992 Harbor seal 

Phoca vitulina (29) 

Harbor porpoise 

Phocoena phocoena (5) 

Rough toothed dolphin 

Steno bredanensis (1) 

Oregon 

Washington 

Yes, yes, no. Unknown H. Braham. Memo to W. 

Aron 

Oct 9 1992, Oct 16 1992 

and December 1992 

1992 Phocids (24) Maine 

Massachusetts 

Connecticut 

Yes, yes, yes Unknown. 

Morbillivirus 

and/or influenza 

suspected 

Geraci et al. 1993. 

Callan et al1995. 

Early 1992. 

1992 Bottlenose dolphins 

Tursiops truncatus

 (220) 

Calhoun and 

Aransas 

counties, 

Texas 

Yes, yes, no Carbamates 

suspected 

Colbert et al. 1999 

Duignan et al. 1996 

Sweeney 1992 

1992-

1993 

California sea lions 

Zalophus californianus

(Approximately 1000) 

California Yes, no, no El Nino, 

50 gunshot 

Greig et al. 2005 

1993 Harbor porpoises 

Phocoena phocoena 

(64) 

Maine 

Massachusetts 

Connecticut 

New Jersey 

Delaware 

Virginia 

North Carolina 

No, no, no Fisheries 

interaction 

Haley and Read 1993 

Read and Murray 2000. 

1993 Pinnipeds (53) 

9 Steller, 15 California 

sea lions, 28 harbor seals, 

1 unknown species sea 

lion 

Washington Yes, no, no. 

Considered 

unusual by the 

Region due to 

strategic stock 

(Steller sea lions) 

involved. 

Gun shot. 

Bullets found on 

gross necropsy 

and X-ray. 

Norberg, pers. comm.. 

8
Year Species and number 

affected 

Location Working Group 

consulted, 

Declared a UME,

Onsite 

coordinator 

appointed 

Cause and 

comments 

References 

1994 Common dolphins 

Delphinus delphis 

(53) 

California Yes, no, no Listed in 

Wilkinson 1996 

as a mortality 

event but not 

formally voted a 

UME by the 

Working Group. 

Etiology unknown 

Reidarson et al. 1998 

1994 Bottlenose dolphins 

Tursiops truncatus 

(72) 

Texas Yes, yes, yes Morbillivirus Lipscomb et al. 1996 

1995 California sea lions 

Zalophus californianus 

(222) 

California No, no, no Leptospirosis Greig et al. 2005 

1996 Sea otters 

Enhydra lutris 

 (68) 

(Cordova), 

Alaska 

No, no, no Malnutrition, 

parasites, cold 

Ballachey et al. 2002 

1996 Right whales 

Eubalaena glacialis 

 (6) 

Florida, 

Georgia 

Yes, yes, no Blast injury 

suspected 

Ridgway 1996 

1996 Florida manatees 

Trichechus manatus

latirostris

(149) 

Florida (west 

coast) 

Yes, yes, yes Brevetoxin Bossart et al. 1998 

Landsberg and Steidinger 

1998 

1996 Bottlenose dolphins 

Tursiops truncatus 

(30) 

Mississippi Yes, yes, no, 

response by 

NMFS lab 

Unknown. 

Coincident with 

algal bloom. 

WG annual meeting report 

1997 notes 

1997 Harbor seals 

Phoca vitulina 

(90) 

California Yes, yes, yes Pseudomonas 

aeruginosa

associated with 

pneumonia. Virus 

suspected. 

None 

1998 California sea lions 

Zalophus californianus

(70) 

California Yes, yes , yes Domoic acid Scholin et al. 2000 

Gulland 2000, 

Silvagni et al. 2005 

1997-

1998 

California sea lions 

Zalophus californianus 

(hundreds) 

California No, no, no El Nino Greig et al 2005 

1999 Harbor porpoises 

Phocoena phocoena 

(216) 

Maine, 

Massachusetts, 

Maryland, 

Virginia, 

North Carolina 

Yes, no, no Oceanographic 

factors suggested 

(Hohn pers. 

comm..) 

Marine Mammal 

Commission, Annual report 

to Congress 

2000 Sea otters 

Enhydra lutris 

(100) 

Cordova, 

Alaska 

No, no, no Parasites ingested 

at a fish 

processing plant 

with discarded 

waste 

Minutes of Working Group 

meeting 2001 

9
Year Species and number 

affected 

Location Working Group 

consulted, 

Declared a UME,

Onsite 

coordinator 

appointed 

Cause and 

comments 

References 

1999-

2000 

Bottlenose dolphins 

Tursiops truncatus 

(115) 

Florida 

(Panhandle) 

Yes, yes, yes Brevetoxin Mase et al. 2000 

1999-

2001 

Gray whales 

Eschrichtius robustus 

(651) 

California, 

Oregon, 

Washington, 

Alaska 

(Canada, 

Mexico) 

Yes, yes, multiple 

OSC one for each 

region, 

Unknown Gulland et al. 2005 

Moore et al. 2001 

2000 California sea lions 

Zalophus californianus 

(178) 

California No, no, no Leptospirosis Greig et al. 2005 

2000 California sea lions 

Zalophus californianus 

(184) 

California Yes, yes, yes Domoic acid Gulland et al., 2002 

2000 Harbor seals 

Phoca vitulina 

(26) 

California Yes, yes, no Unknown. Viral 

pneumonia 

suspected. 

2001 Bottlenose dolphins 

Tursiops truncatus

(35) 

Florida 

(Indian River 

Lagoon) 

Yes, yes, yes Unknown. 

Saxitoxin present 

in puffer fish. 

Barros 2001 unpublished 

Leighfield 2002 unpublished 

2001 Harp seals 

Phoca groenlandica

(453) 

Maine 

Massachusetts 

No, no, no Unknown Harris et al. 2002 

2001 Hawaiian monk seals 

Monachus schauinslandi

(11) 

Hawaii 

(Northwest 

Hawaiian 

Islands) 

Yes, yes, yes Malnutrition Antonelis et al. 2001 

2002 Multispecies 

(Common dolphin, 

California sea lion, sea 

otter) approx. 500 

California Yes, yes, yes Domoic acid Mazet et al. 2005 

2002 Florida manatees 

Trichechus manatus 

latirostris 

(34) 

Florida (west 

coast) 

Yes, yes, yes Brevetoxin Flewelling et al. 2005 

2003 Multispecies 

(Common dolphin, 

California sea lion, sea 

otter) approx. 500 

California No, no, no Domoic acid 

2003 Sea otters 

Enhydra lutris

(69) 

California Yes, yes, yes Ecological factors Draft report to WG 

2003 Beluga whales 

Delphinapteus leucas 

(20) 

Cook Inlet, 

Alaska 

No, no, no Increased 

detection, 

ecological factors 

Vos and Shelden 2005 

10
Year Species and number 

affected 

Location Working Group 

consulted, 

Declared a UME,

Onsite 

coordinator 

appointed 

Cause and 

comments 

References 

2003 Large whales (16 

humpback, 1 fin, 1 

minke, 1 pilot, 2 

unknown) 

Maine Yes, yes, yes Unknown. 

Saxitoxin and 

domoic acid 

detected in 2 and 

3 humpbacks 

respectively. 

2003- 

2004 

Harbor seals 

Phoca vitulina 

Minke whales 

Balaenoptera 

acutorostrata 

Gulf of 

Maine-EEZ 

Yes, yes, yes Unknown Touhey, pers. comm. 

2003 Florida manatees 

Trichechus manatus

latirostris 

(96) 

Florida (west 

coast) 

Yes, yes, yes Brevetoxin 

2004 Bottlenose dolphins 

Tursiops truncatus 

(107) 

Florida 

(Panhandle) 

Yes, yes, yes Brevetoxin Draft report to WG, Gaydos, 

in prep. 

Flewelling et al. 2005 

2004 Small cetaceans 

(67) 

Virginia Yes, yes, yes Unknown Barco, report to WG 

2004 Small cetaceans North Carolina Yes, yes, yes Unknown Hohn, pers. comm.. 

2004 California sea lions 

(405) 

California. 

Oregon, 

Washington, 

Canada 

Yes, no, no Leptospirosis Raverty et al. 2005 

2005 Manatees 

Trichechus manatus 

Bottlenose dolphins

Tursiops truncatus 

(ongoing Dec 2005 )

Florida (west 

coast) 

Yes, yes, yes Brevetoxin. 

Bird, turtle and 

fish kills 

associated with 

the event 

2005 Harbor porpoises 

Phocoena phocoena 

(ongoing at Dec 2005) 

North Carolina Yes, yes, yes Unknown Hohn, pers. comm.. 

2005 California sea lions 

Zalophus californianus 

Northern fur seals 

Callorhinus ursinus 

(several hundred) 

California Yes, no, no Domoic acid Goldstein et al. 2005 

2005 Large whales North Atlantic Yes, yes, yes Domoic acid 

suspected 

Touhey pers. comm.. 

2005-

2006 

Bottlenose dolphins 

Tursiops truncatus 

(ongoing at Dec 2005) 

Florida Yes, yes, yes Brevetoxin 

suspected 

11
Figure 1. Stranding Network LOA Holders and Number of Mortality Events in Each Region. 

Alaska

0

1

2

3

4

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

Year

Number of MEs

pinniped

otter

cetacean

12
North West Region

0

1

2

3

4

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

Year

Number of MEs

pinniped

cetacean and pinniped

cetacean

13
Hawaii

0

1

2

3

4

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

year

number of MEs

pinniped

14
South West Region

0

1

2

3

4

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

Year

Number of MEs

otter

pinniped

cetacean, pinniped, otter mixed

cetacean

15
South East Region

0

1

2

3

4

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

Year

Number of MEs

manatee

cetacean

16
North East Region

0

1

2

3

4

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

Year

Number of MEs

pinniped

cetacean and pinniped

cetacean

17
Figure 2. Marine Mammal Mortality Events in Different Taxa, 1978-2005. 

0

1

2

3

4

5

6

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

Number of mortality events

sirenian

pinniped

sea otter

mixed taxa

cetacean

cetacean

39%

mixed taxa

7%

pinniped

36%

sea otter

9%

sirenian

9%

cetacean

mixed taxa

sea otter

pinniped

sirenian

18
Figure 3. Identified Causes of Marine Mammal Mortality Events, 1978-2005 

0

1

2

3

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

Number of mortality events

Influenza

Ciguatoxin

saxitoxin

parasites

oil

morbillivirus

malnutrition

leptospirosis

human interaction

domoic acid

brevetoxin

Brevetoxin

20%

Ciguatoxin

3%

Domoic acid

17%

Human 

interaction

9%

Influenza

6%

Leptospirosis

15%

Malnutition

12%

Oil

3%

Morbillivirus

6%

Parasites

3%

Saxitoxin

6%

19
Figure 4. Unknown Causes of Marine Mammal Mortality Events 

0

1

2

3

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

Number of mortality events

20
Figure 5. Causes of Mortality Events in 1978-1992 Compared to 1993-

2005.

1978 to 1992

Brevetoxin

6%

Malnutition

11%

Morbillivirus

6%

Oil

6%

Parasites

0%

Saxitoxin

11%

Unknown

32%

Ciguatoxin

6%

Influenza

11%

Domoic acid

0%

Leptospirosis

11%

Human interaction

0%

Brevetoxin

Domoic acid

Human interaction

Leptospirosis

Malnutition

Morbillivirus

Oil

Parasites

Saxitoxin

Unknown

Ciguatoxin

Influenza

1993 to 2005

Brevetoxin

16%

Domoic acid

16%

Human interaction

8%

Leptospirosis

Malnutition 8%

5%

Unknown

41%

Morbillivirus

3%

Oil

0%

Parasites

3%

Saxitoxin

0%

Influenza

0%

Ciguatoxin

0%

Brevetoxin

Domoic acid

Human interaction

Leptospirosis

Malnutition

Morbillivirus

Oil

Parasites

Saxitoxin

Unknown

Ciguatoxin

Influenza

21
Efforts to Improve Response

To date, NMFS has implemented a variety of approaches to improve responses to marine 

mammal UMEs. These have been achieved with a limited budget and few staff, and have relied 

upon in-kind work and funding from stranding network participants and collaborating 

researchers. 

A National Contingency Plan for response to UMEs was published in 1996 (Wilkinson 1996). 

This has details of the UME legislative process; outlines public health and welfare concerns and 

advance planning needs; gives considerations required for live animal management; lists 

methods for tissue collection, preservation and shipping; post-event activities; and gives lists of 

stranding network members and agencies. Since then, several species specific contingency plans 

have been developed with greater details about response logistics. A contingency plan for 

responding to mortality of Florida manatees was developed in 1997 and has been regularly 

updated by the U.S. Department of the Interior (Geraci and Lounsbury 1997) and a plan for 

unusual mortality of Hawaiian monk seals was developed in 2004 (Yochem 2004). There are 

also response plans for events involving oil discharges or releases of hazardous substances 

developed by NOAA and by the USFWS distributed through its Contaminants Program (USFWS 

1995). 

 

In 1999, the addition of the international members as liaisons on the Working Group greatly 

enhanced communication amongst agencies in Mexico, the U.S. and Canada concerned with 

health and conservation of marine mammals. Wildlife disease surveillance is an international 

concern, as not only is the impact of the disease on transboundary marine mammal stocks 

important, but disease outbreaks can have important impacts on trade and movement of domestic 

animals and animal products. With the increased use of the internet for disease reporting, the 

public and scientific community is rapidly informed of emerging diseases, and wildlife disease 

surveillance needs to cross national boundaries to be effective. 

Additional preparation of the stranding network for response to a UME has been achieved by 

training members likely to be On-site Coordinators (OSC). A training workshop was held in 

October 2003 at the National Conservation Training Center that covered contingency planning, 

necropsy techniques, data management, report writing and media management. The OSCs for 

two events in 2004 had attended this training prior to becoming OSCs. Supplementing these 

detailed training sessions, and involving larger numbers of stranding response personnel were 

two National Stranding Conferences, held in December 1987 and April 2005. 

A common concern for network members when responding to dead marine mammals is the 

availability of diagnostic resources that can examine samples collected from stranded animals. 

To address this concern NMFS has ongoing contracts with several laboratories to provide 

histology, serology and bacterial culture diagnostics on samples submitted from stranding 

network members. These contracts improve the quality and reliability of data resulting from 

investigations by eliminating potential problems associated with inter-laboratory variability, and 

provide opportunities to establish acceptable levels of quality assurance and quality control. The 

contacts and methods for sample collection and submission for these services were provided 

22
during the OSC training in 2003. However, it should be noted that the long-term availability of 

contracted independent laboratories is not guaranteed, and in the near future several crucial labs 

will cease operations, leaving significant gaps in diagnostic capabilities. 

A limited amount of sample archiving from animals dying during UMEs has been achieved 

through the National Marine Mammal Tissue Bank program, jointly managed by the NMFS and 

the National Institute of Standards (NIST). Tissues banked include blubber, liver, kidney and 

muscle, which have been used for retrospective toxicological analyses. 

 

CHALLENGES AND FUTURE DIRECTIONS 

Although there are four aims of responses to UMEs: to minimize deaths, determine the cause of 

the event, determine the effect of the event on the population, and to identify the role of 

environmental variables in the event, only the first two of these have been significantly 

addressed since the UME program was established in 1992. Efforts to minimize deaths have 

improved as an increasing number of stranding network facilities employ veterinarians to advise 

on medical care of stranded marine mammals, and the field of marine mammal medicine has 

developed considerably over the last 10 years (Dierauf and Gulland 2001). Identification of the 

cause of mortality events has been achieved in just over half (56 percent) of the investigations, 

some of these resulting in the detection of novel disease syndromes in marine mammals (Geraci 

et al. 1989, Lipscomb et al. 1994, Bossart et al. 1998, Scholin et al. 2000). Identification of novel 

diseases requires significant resources and collaboration, thus achieving this through 

investigations of mortality of wild mammals is a considerable accomplishment. However, trends 

in the frequency of these diseases, the impact of environmental change on these diseases, and the 

effects of these mortality events on host populations cannot be determined from the data 

currently available to the UME program, given the limited resources available. Without this 

information, the status of marine mammal health and the impacts of anthropogenic activities and 

environmental factors (e.g. climate change) on it cannot be assessed. Thus the first two purposes 

of Title 1V of the MMPA are not being adequately met by the current program to investigate 

marine mammal mortality events. Specific issues that need to be addressed to improve the ability 

of the stranding network to respond successfully to UMEs are discussed below.

Data Quality and Management 

The results of the majority of these marine mammal mortality event investigations have not been 

published in peer reviewed journals, nor in many cases have technical reports been filed for the 

administrative record with the NMFS or USFWS (Table 1). Thus efforts to compile data on 

mortality events have been severely compromised, and have relied heavily on personal 

communications and anecdotal reports. Furthermore, not all marine mammal mortalities have 

been assessed consistently to determine whether or not they fulfill the criteria for UME 

classification. In some cases, significant die-offs of marine mammals occurred, but neither the 

National Stranding Coordinator nor the Working Group Executive Secretary were notified, and 

the event was not recorded in the UME database. The stranding data have, however, been 

recorded by local networks, and sometimes published in the peer reviewed literature. 

Notification of the National Stranding Coordinator, and consultation of the Working Group on 

23
whether or not an event is a UME, have both been somewhat arbitrary, and have depended upon 

the levels of concern, the degree to which local stranding network responder resources have been 

strained by stranding increases, and involvement of the stranding network responder and the 

regional stranding coordinator. This means that the UME record is not a reliable dataset from 

which to assess trends in marine mammal health and frequency of die-offs. 

For example, Table 1 lists one mortality event of California sea lions (Zalophus californianus) in 

1991 due to leptospirosis about which the Working Group was consulted. However, leptospirosis 

epidemics also occurred in 1994, 1995, 1999 and 2000 (Greig et al. 2005). Each of these had 

higher sea lion mortality than in 1991, yet the neither the National Stranding Coordinator nor the 

Executive Secretary were notified. In another example, there were increased strandings of 

malnourished sea lions in California in 1992, some of which were gunshot, and this event was 

declared a UME. In 1998, twice as many sea lions stranded associated with El Niño conditions 

(Greig et al. 2005), but this event was not reported to the National Stranding Coordinator. 

A second limitation of the current UME process for assessing the frequency of disease outbreaks 

in marine mammals and using the frequency of UMEs as a metric of health is that it does not 

include data on gradual increases in single strandings that might reflect increases in mortality, or 

mass strandings. Stranding network members submit Level A data (species, age class, size, 

strand location, date, sign of human interaction) to the National Stranding database, but this does 

not include disease data or cause of mortality. Trends in individual strandings or mass strandings 

may provide important insights into the role of environmental variables in UMEs (the third aim 

of UME response). 

The third limitation to the data in the UME database as it is currently structured is that detection 

of UMEs relies upon an efficient stranding network that detects stranded animals, has the 

training and expertise to examine animals and collect the required samples and data, and submits 

the data to a centralized database. Changes in the baseline stranding data are used to detect 

UMEs, using the criteria listed above. In many areas of the U.S., there is poor detection rate of 

stranded marine mammals, due to low human population density, social attitude, few trained 

LOA Holders (Figure1), and lack of funding to support response to stranded animals. Detection 

of stranded marine mammals will also be influenced by weather conditions affecting human 

activity on beaches, as well as by tides and currents affecting carcass deposition. 

To address these limitations and improve the utility of the data collected through the UME 

response, the following actions are recommended: 

1. Expand the National Stranding database to: 

a. Include data on cause of death and disease investigations. 

b. Integrate single stranding, mass stranding and UME stranding data into one real 

time searchable database with a method for rapid identification of these “group” 

events. 

c. Develop data sharing protocols and agreements to facilitate collaborations and 

extensions of analyses. 

24
2. Improve the stranding network’s surveillance capabilities by: 

a. Dedicating funding sources (e.g. Prescott program) to stranding network members 

to ensure consistent levels of response capabilities for surveillance to detect 

UMEs. This should include responders who are employed by federal agencies 

whose primary employment duties do not include stranding response or UME 

investigation. 

b. Holding regular training workshops for LOA Holders. 

c. Increase data collection requirements from LOA Holders during UMEs. 

d. Directing training and funding above to areas of the network with poor coverage 

of the coastline and detection rates (Figure1). 

e. Developing protocols for regional stranding coordinators on event notification. 

3. Require development and submission of final reports and encourage peer reviewed 

publications on UME investigations by: 

a. Requiring final reports to be submitted from UMEs as a condition of receiving 

funds. 

b. Funding report writing by qualified personnel. 

c. Fostering research collaborations through workshops and seminars. 

4. Review of the reports on UMEs by the Working Group, and incorporate 

recommendations on improved response and investigation based on the reports into 

future UME responses. 

Administrative Process 

Responses to UMEs have been hindered by the administrative process involved in the 

declaration of a mortality event as unusual, as well as by logistics on site. Most stranding 

network responders do not have the extra financial resources immediately at hand to mount 

effective responses to UME events, and rely upon the federal funding available through the UME 

program of the MMHSRP to do so. Thus there is a need for a rapid response from the agency to 

a notification by a LOA Holder that a UME may be occurring. Section 404 of the Marine 

Mammal Health and Stranding Response Act provides the framework for responding to UMEs. 

Essentially, the UME coordinator is required to contact as many members of the Working Group 

as possible within 24 hours of a Regional Stranding Coordinator or standing network member 

contacting the NMFS, each person in the Working Group then responds within 24 hours with a 

vote on whether or not a UME is occurring, and, unless time is needed to gather additional 

information as requested by any member of the Working Group, determination of whether or not 

an UME is occurring takes place within 48 hours of a Regional Stranding Coordinator contacting 

the NMFS about a possible event. Over the last 10 years, however, many events have not been 

addressed within this time frame, and it has taken weeks to months for events to be declared 

UMEs. This has limited network member’s abilities to respond to the event, and has required 

stranding network responders to utilize their own funds for UME response. Furthermore, there 

has been limited communication between the field investigation team and the Working Group. 

25 
Once a UME is declared, an appropriately qualified OSC should be designated to mobilize and 

manage the response to the event. The OSC is responsible for directing the response, and needs 

to have strong management and leadership capabilities, highly effective communication skills, 

the capacity to make decisions with minimal use of intermediaries, the ability to access 

information and expertise including interagency expertise, and, a familiarity with the 

Contingency Plan and the Stranding Network and sufficient time released from regular job 

obligations to serve as coordinator. The OSC is also responsible for preparing a report 

containing results of investigations and recommendations for subsequent monitoring or 

management activities. Despite training in 2003, few stranding network members currently have 

the skills or the flexibility in their work schedules to become OSCs during events, and fewer 

have had time to complete reports on UMEs after the events are over. Furthermore, the work 

load of all these responsibilities is too much for one person, especially one who often has another 

job. 

A third concern with the process involved in declaring mortality events UMEs and mounting 

effective responses is that some events involve multiple species managed by separate agencies, 

and communication amongst these can be poor. For example, in California in 2002, sea otters 

(Enhydra lutris nereis), California sea lions and common dolphins (Delphinus delphis) died 

during the UME. Sea otters are managed by the USFWS, examined post mortem by the state 

California Department of Fish and Game and data on their population numbers collected by the 

U.S. Geological Survey, whereas NMFS is responsible for management of sea lions and 

dolphins. Lack of an efficient method of communication between these agencies delayed 

allocation of financial resources to the investigation, and limited interpretation of stranding data 

and detection of associations between mortality and environmental variables. 

To address these concerns over the administrative process, the following are needed: 

1. A full time dedicated Executive Secretary to: 

a. Track the administrative process. 

b. Develop effective inter and intra-agency communication. 

c. Facilitate communication between the working group and the field investigation 

team. 

d. Act as an off-site coordinator. 

2. Weekly communication between the Working Group and the OSC. This could be 

achieved by dedicating one member of the Working Group as the liaison for each UME, 

and would provide the Working Group with real time information on the UME 

response, and the OSC with moral and logistic support. 

3. Trained personnel with allocated time to be the OSC on emergency response and 

members of teams employed during responses to UMEs. These teams would consist of 

at least three people, from which would be drawn appropriate response teams for 

specific events, based on the existing abilities and needs of the local stranding networks. 

Availability of team members would be accommodated with a retainer and NMFS 

would pay for all travel associated with the response. Teams are described in more 

detail below. 

26
Response Logistics 

Logistical constraints in the field have limited investigations into the causes of UMEs, with the 

result that many UMEs have unknown etiologies. These constraints include lack of resources in 

the field, such as lack of trained personnel to examine stranded animals and collect appropriate 

samples, lack of equipment to collect samples with, and lack of heavy equipment or transport to 

access, store or dispose of carcasses. Delayed access to animals for sampling limits the quality of 

the samples that can be collected as decomposition affects most analyses and diagnostic tests 

(Geraci and Lounsbury 1993, Rowles et al. 2001). There is considerable variation in the level of 

training among network members, resulting in variation in the quality of post mortem 

examination of carcasses. For example, in northern California, marine mammals that live strand 

and die are examined fully at post mortem by veterinarians and board-certified pathologists, 

whilst dead stranded animals are examined by museum curators and typically only archival skull 

material is collected from these cases. Once samples are collected from marine mammals, they 

are shipped to diagnostic laboratories or banked for future analyses. There are a limited number 

of laboratories with tests adapted for these species, and many of these have no quality control 

program. Thus test results are often delayed and unreliable. Also, the future of some of these 

crucial laboratories is in jeopardy as key staff members retire or move to other positions. 

Problems will arise from the lack of availability of diagnostic tests, or from an inability to 

calibrate test results across past and future diagnostic labs, as has occurred multiple times during 

long-term health studies of free-ranging bottlenose dolphins (Wells et al. 2004). 

There is no formal archiving system for samples collected during UME responses. Samples 

banked from UME events are often stored in freezers with no emergency generator for use in the 

event of power outages, and have limited tracking data by network responders and are often 

untraceable years after an event is over. This makes retrospective analyses impossible. As novel 

diseases and toxins are identified it is not possible to re-examine earlier UMEs to determine 

whether they played a role. For example, in 2002 domoic acid was identified as the cause of a 

UME of common dolphins in California, after being first identified as a cause of marine mammal 

mortality in 1998 (Scholin et al. 2000). There was a die-off of common dolphins in California in 

1994 with very similar features to the 2002 event. However, as domoic acid had not been 

considered at the time, it was not tested for. After the 2002 event, efforts to re-examine the 1994 

event to determine whether domoic acid could have been the cause were limited by the lack of 

archived tissues or fluids for examination. 

To address these logistical difficulties, the following actions are recommended: 

1. Enhance resources of stranding network members by: 

a. Regular training in necropsy techniques, sample collection, archiving and 

shipping to all network responders. 

b. Stocking each region with supplies for emergency sampling of marine mammals. 

c. Identifying appropriate storage facilities in each response area. 

d. Developing a permanent response team available to rapidly mobilize during a 

UME with a trained pathologist, research assistant and a data manager. 

e. Posting response, sampling and shipping protocols to a website for easy access. 

27
f. Identifying funds for carcass handling and disposal so that large whales can be 

towed ashore for examination then disposed of. 

2. Develop a centralized national sample archiving system to include fluids and tissues from 

animals during UME events. 

3. Improve availability and quality of diagnostic tests performed on samples from marine 

mammals by: 

a. Identifying and funding dedicated laboratories for pathology, infectious diseases, 

biotoxin and contaminant analyses. 

b. Developing a quality assurance program for laboratories analyzing marine 

mammal samples. 

c. Ensuring collection of suitable samples by establishing protocols for the 

investigation of specific events that are known to occur, such as domoic acid 

toxicosis, brevetoxicosis, leptospirosis, beaked whale strandings, morbillivirus 

and influenza epidemics, and human interactions. 

4. Develop the means to fund crucial aspects of a response that are currently not allowed, 

such as salary support for personnel dedicated to a UME, and for carcass disposal. 

Impact on Population and Role of Environmental Parameters

Two of the aims of UME responses, determining the impact of the event on the host population, 

and determining the role of environmental parameters in the mortality event, have rarely been 

addressed during UME investigations. To achieve these aims, 

1. The MMHSRP needs to be integrated with the stock assessment programs of the NMFS 

and population monitoring programs of the FWS and USGS, as well as other federal 

programs addressing environmental and climate variables impacting marine mammal 

health (e.g. the Ecology and Oceanography of Harmful Algal Blooms). Of equal 

importance to performing diagnostic analyses of tissues from stranded animals is the need 

to identify their stock of origin, through genetic or other techniques. Stock identification 

facilitates evaluation of population impacts and recovery, and the identification of 

geographical ranges of affected animals, facilitating investigation of exposure to 

environmental factors. Integration with the regular, ongoing stock assessment process 

will not only enhance knowledge about UME impacts, but will also inform managers 

regarding factors influencing scheduling of stock assessment updates. 

2. A research plan addressing factors predisposing marine mammal populations to mortality 

events must be developed and funded. 

28
ACKNOWLEDGEMENTS 

I thank all members of the National Marine Mammal Stranding Network for their hard work in 

collecting the data presented here and caring for the stranded animals, and the staff of the 

National Marine Fisheries Service for managing the Marine Mammal Health and Stranding 

Program, especially Teri Rowles, Janet Whaley, Trevor Spradlin, Sarah Wilkin, Michelle 

Ordono, Angela Collins-Payne, Joe Cordaro and Brent Norberg. I also thank Denise Greig for 

assistance with this manuscript, and Randy Wells, Tim Ragen, Katie Touhey, Aleta Hohn, Ailsa 

Hall, Elsa Haubold and Tracey Goldstein for comments on earlier versions of this report. 

29 
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