SOLVING THE MYSTERIES OF MARINE MAMMAL UNUSUAL MORTALITY EVENTS

December 15, 2003 — Imagine 700 dead bottlenose dolphins washing up on the mid-Atlantic coastline or dozens of California sea lions seizuring and dying on a public beach. Now imagine discovering 273 dead gray whales along their migratory route between Mexico and Alaska, followed by discovering another 377 dead gray whales the next year. Unfortunately, these scenarios don’t need to be imagined because they actually occurred over the past fifteen years, along with 26other events classified as marine mammal “Unusual Mortality Events” or UMEs. Responsibility for investigating the causes of UMEs does not fall to the cast of TV’s “CSI” team, although many of the same processes utilized by detectives and criminal forensic scientists are involved. Instead, it’s members of the national marine mammal stranding networks who investigate UMEs in coordination with NOAA Fisheries’ Marine Mammal Health and Stranding Response Program to solve the mysteries. While television detectives glamorously determine “whodunit” within an hour (including commercial breaks), in real life the investigation into an UME can take weeks, months or even years (and without a theme song or support from advertisers).

An UME is a series of marine mammal strandings that are unexpected, involve a significant die-off of any marine mammal population and/or demand an immediate response. According to Janet Whaley, D.V.M., the National Marine Mammal Stranding Network Coordinator for the MMHSRP, “It's important that we understand marine mammal UMEs because they can serve as barometers of ocean health, giving us insight into larger environmental issues which may also have implications for human health and welfare.”

Typically, UMEs are initially detected by members of the volunteer local marine mammal stranding networks, which are established in all coastal states. For all cetaceans and most pinnipeds, the stranding network is facilitated by the MMHSRP and six Regional Coordinators. Whaley adds, “In order to know if something is unusual or unexpected, you have to know what is normal. The marine mammal stranding network is the first line of detection and the principal line of defense.”

What happens if a Stranding Event Occurs?
If a stranding event is suspected to be abnormal, NOAA Fisheries will consult with the Working Group on Unusual Marine Mammal Mortality Events to determine if the event qualifies as an UME. The Working Group was established by the U.S. Congress under Section 404 of the Marine Mammal Protection Act as an advisory board to the Secretary of Commerce and Secretary of the Interior¹. It is comprised of 12 U.S. members (who serve three-year terms), two international observers (one from Canada and one from Mexico), and four permanent U.S. government agency representatives from NOAA Fisheries, the U.S. Fish and Wildlife Service, the Marine Mammal Commission and the U.S. Environmental Protection Agency. Working Group members come from a variety of backgrounds and organizations, including pathologists, toxicologists, veterinarians, biologists and population dynamics ecologists from government and non-government organizations.

Upon receiving a request for consultation, the Working Group has 24 hours to evaluate the information presented and determine if an event qualifies as an UME and if an “Onsite Coordinator” is needed to facilitate the response. In addition, during an ongoing UME investigation, the Working Group is charged with:

• Determining when response actions are no longer necessary,
• Guiding the investigation and
• Developing (and periodically reviewing and revising) a contingency plan to address foreseeable situations

Within 48 hours of the Working Group’s recommendation, the Secretary of Commerce or the Interior must make the official determination that an UME is in progress, notify the stranding network participant and designate an Onsite Coordinator, if needed. In addition to the Onsite Coordinator, an Offsite Coordinator, investigative team and administrative team are assembled.

What Makes a Stranding Event “Unusual?”
The Working Group has established seven criteria to evaluate whether a mortality event qualifies as “unusual,” which take into account marine mammal population dynamics, biology and environmental factors. A single criterion or combination of any criteria may be used to declare an UME.

Frances Gulland, Vet. M.B., M.R.C.V.S., Ph.D., current chair of the Working Group and director of veterinary science at The Marine Mammal Center in Sausalito, Calif., explains “Mortality events are often a result of a combination of factors modifying the health of a marine mammal, each one of which alone would not necessarily result in death of the animal. It is important to determine not just the ultimate cause of death, but predisposing factors, and this requires a comprehensive investigation.” She sited the example of the gray whale UME in 1999-2001, when whales died along the West Coast from boat strikes, viral encephalitis and/or domoic acid toxicity — all seemingly separate events. However, the observed causes of death were likely secondary to severe malnutrition. Suffering from a lack of food, whales were observed feeding in non-traditional sites where they were exposed to additional ship traffic and areas with algal blooms.

Official designation as an UME makes funding available for the investigation through the Marine Mammal Unusual Mortality Event Fund, which was established by Congress and is managed by NOAA Fisheries and the National Fish and Wildlife Foundation. This funding helps to ensure complete collection and analysis of samples and is an important source of financial support for the marine mammal stranding networks to respond to UMEs. Members of the public who want to contribute to the fund and help support UME investigations can make donations to the National Fish and Wildlife Foundation.

The UME Investigation Experience
An UME involving primarily humpback whales in the Northeast United States and Canada was declared during the summer of 2003. Katie Touhey, program director for the Cape Cod Stranding Network, consulted with NOAA Fisheries and the Working Group following the discovery of several dead whales floating in the open ocean east of Cape Cod. Following the determination that an UME was in progress, Touhey was designated the Onsite Coordinator, thereby responsible for coordinating and directing the investigation, including “on the ground” logistics and preparing the event final report.

Touhey describes the experience: “It’s solving a mystery, or at least trying to. The support I received from NOAA Fisheries at both the regional and national levels helped me to focus on the tasks at hand, which included administration, as well as scientific investigation of the event. The primary goal was to sample as many carcasses as possible.”

Conducting necropsies on large whales, such as humpbacks, stranded on the beach or close to shore is routine for Touhey’s team. However, the carcasses of the animals involved in this UME were floating more than 150 miles offshore. “With the help of the crew of the U.S. Coast Guard Cutter Tahoma, we were able to gain access to three humpback whale carcasses and one pilot whale carcass floating on Georges Bank. Necropsy and sampling involved the use of a small rigid hulled inflatable boat launched from the cutter.” Touhey, Michael Moore (Woods Hole Oceanographic Institute) and Jooke Robbins (Center for Coastal Studies) sampled the carcasses, which proved to be a difficult task. “In order to collect the necessary samples, Moore had to literally stand on (and in) the floating whales, keep his balance in choppy seas and watch for sharks, which were feeding on the carcasses.”

“After the two and half days at sea collecting samples, my daily work associated with the UME involved overseeing the packaging and shipping of the samples to several labs for viral and biotoxin analyses,” said Touhey. “In addition, much of my time was spent tracking carcasses and working with both vessel and aerial survey teams to maintain a sighting database to catalog the whales that were found. The not-so-glamorous job of tracking expenses and submitting invoices for payment also became a daily task. I think the most important responsibility of the Onsite Coordinator is acting as a clearinghouse for information. Collating the data and then maintaining open lines of communication with the Working Group and the Investigative Team are essential elements of a successful UME response. They are also two of the most challenging aspects.”

Traces of domoic acid, a naturally occurring biotoxin produced by algae, have been found in tissue samples taken from five of the 21 large whales that died during the UME. Domoic acid causes a condition known as amnesic shellfish poisoning and has been responsible for whale and other mammal deaths on the West Coast.

Since 1991, marine mammal die-offs have been comprehensively investigated as a result of more focused scientific inquiry. Twenty-nine die-offs have been designated UMEs and the thousands of animals involved have been thoroughly examined thanks to support and guidance from the UME program. Species affected include right whales, gray whales, manatees, humpback whales, California sea lions, bottlenose dolphins, common dolphins and harbor seals. Nine events were caused by biotoxins, five were attributed to infectious disease and no specific cause has yet been determined in an additional nine cases.

Between October 13-17, 2003, the MMHSRP held a workshop at the National Conservation Training Center in Shepherdstown, W.Va. to train members of the marine mammal stranding networks how to serve as UME Onsite Coordinators. The workshop involved more than 50 participants from the U.S. and Mexico, including representatives from the marine mammal stranding networks, NOAA Fisheries, USFWS, NOAA Ocean Service, Marine Mammal Commission, Armed Forces Institute of Pathology, Smithsonian Institution and U.S. Navy. The workshop included instruction on policies and procedures for administering UMEs, as well as “hands on” training in necropsy procedures, media and public outreach and data management.

Other MMHSRP Programs
The MMHSRP, also known as “Team Health” for NOAA Fisheries, has three primary mandates:

• To facilitate the collection and dissemination of reference data on health of marine mammals and health trends of marine mammal populations in the wild,
• To correlate marine mammal health with physical, chemical and biological environmental factors and
• To coordinate effective responses to UMEs.

To fulfill these mandates, the MMHSRP is comprised of five components. In addition to the stranding network and UME investigation responsibilities discussed above, the MMHSRP also conducts biomonitoring, analytical quality assurance and tissue/serum banking.

• Biomonitoring: In recent years, high concentrations of potentially toxic substances in marine mammals and an increase in new diseases have been documented. Scientists are investigating the possible links between these toxic substances and marine mammal mortality events. These studies are contributing 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. Since marine mammals share habitats and food sources with people, monitoring their health can provide scientists with important insight about the quality of the marine environment and potential impacts on human health and welfare. The Northwest Fisheries Science Center is the NOAA Fisheries lead for the contaminant component of the MMHSRP's biomonitoring program.
• Analytical Quality Assurance: The Analytical Quality Assurance aspect of the MMHSRP was designed to ensure accuracy, precision, level of detection and comparability 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 National Institute of Standards and Technology lab in Charleston, S.C., implements the AQA.
• Tissue/Serum Banking: The MMHSRP and the NIST Charleston lab have partnered to develop and curate the National Marine Mammal Tissue Bank, which was formally established under the MMPA in 1992. The program provides protocols and techniques for the long-term storage of tissues from marine mammals for retrospective contaminant analyses. Tissues archived in the Tissue Bank have greatly aided UME investigations long after the initial stranding events by providing reference materials and historical samples for comparative analyses.

The work of the MMHSRP team involves interagency and international collaborations, and actively links with marine mammal rehabilitation programs to investigate and understand marine mammal mortalities and the health of wild populations. Investigating UMEs is a team effort requiring cooperation from experts in all branches of marine and veterinary science. As advancements are made in the medical and forensics fields, our ability to respond to UMEs continues to improve. “We want to get to the point where we can predict UMEs and mitigate them,” says Whaley. “We have to be able to differentiate between naturally occurring situations and ones caused by humans so we can minimize the negative impacts to marine mammals and people alike.”

Notes
¹Under the Marine Mammal Protection Act, jurisdiction for marine mammals is shared between NOAA Fisheries (which is under the Department of Commerce) and the U.S. Fish and Wildlife Service (USFWS, which is under the Department of the Interior). NOAA Fisheries is responsible for managing all species of cetaceans (whales, dolphins and porpoises) and most species of pinnipeds (seals and sea lions). USFWS is responsible for managing manatees, sea otters, walrus and polar bears.

Relevant Web Sites
NOAA

Unusual Mortality Events

NOAA Fisheries’ Marine Mammal Health and Stranding Response Program

Marine Mammal Stranding Network Participants

NMFS Regional Stranding Coordinators

NOAA Fisheries

Working Group on Unusual Marine Mammal Mortality Events

Marine Mammal Protection Act

Criteria for Determining an Unusual Marine Mammal Mortality Event

NOAA Marine Mammal Unusual Mortality Event Fund

NOAA Ocean Service

NOAA MMHSRP Biomonitoring

NOAA MMHSRP Analytical Quality Assurance Program

NOAA MMHSRP Tissue/Serum Banking

John H. Prescott Marine Mammal Rescue Assistance Grant Program

Northwest Fisheries Science Center

Media Contact:
Susan Buchanan or Connie Barclay, NOAA Fisheries, (301)713-2370.