The Marine Mammal Health and Stranding Response Program was developed under Title TV of the Marine Mammal Protection Act as a response to the 1987-88 Atlantic bottlenose dolphin die-off. This multi-agency program has developed a bio-monitoring component, an archival component, a stranding component, an unusual mortality response component and a Quality assurance component to address the issues of marine mammal population health. The basic parameters evaluated include incidence and types of disease, incidence of serious injury and mortality related to human interactions, and levels and effects of contaminants. Bio-monitoring and archival samples are collected from animals taken incidentally in commercial fisheries, taken in Native American subsistence hunts, live captured and released and from stranded animals. Once a problem is identified through the bio-monitoring component, specific aspects of the program are designed to characterize the problem and investigate unusual events or mortalities which impact marine mammal populations. The information gained from this program is used for management decisions by NMFS and FWS who serve as the stewards of marine mammals and their environment.

Marine mammal stranding networks have been established in each of the NMFS regions and consist primarily of volunteers who respond both to live and dead strandings. In 1995, network members reported 898 cetacean strandings and 1973 pinniped strandings. More live strandings of single cetaceans were recorded in 1995 due, in part, to the increased efforts of stranding volunteers to respond more quickly to events and to increased reporting of strandings to the volunteers. The total number of reported strandings (live and dead) was the lowest of any year since 1990. Among the interesting trends is a continuing increase in the number of arctic seals stranding in the Northeast region of the United States. In particular the number of harp seals has risen dramatically from a 1989 level of 3 to the current 1995 level of 78. This increase may reflect an expansion of the range and numbers for some seal species. Evidence of human interactions such as gun-shots, entanglement in fishing gear, mutilation, boat strikes, and entrainment in nuclear power plants were reported. Of the total 213 animals which showed strong evidence of human interactions, 80 were fisheries related, 14 were ship strikes, 54 were shot, 13 were mutilations, 7 were debris entanglement and ingestion, 27 were entrainments and 4 were other. In 1995 no unusual mortality event involving marine mammals was noted. Investigations are still continuing regarding the increase in humpback whale strandings in the mid-Atlantic.

Live animal capture and release methods are used to assess the relative health and reproductive status of dolphin populations and to identify populations at risk. The goals of this project are to characterize the overall health of the coastal stocks, and provide quantitative estimates of the level of indirect human-induced mortality and the impacts of contaminants on the reproductive rate. Ultimately this information will be used with incidental take data to accurately assess stock status, predict recovery times and to identify stocks which may become depleted due to the impacts of contaminants on health and productivity. To this end, comprehensive health assessments of coastal bottlenose dolphins have been conducted at two sites: one in the Gulf of Mexico (36 animals) and one in the mid-Atlantic (31 animals). A workshop was conducted in 1993 to develop a quantitative model of health assessment and this model is being tested and refined. Parameters collected/analyzed in the assessment protocols include: CBC, serology, blood chemistries, skin/blubber biopsies (for genetic and contaminant analyses), cultures, urinalyses, ultrasonography (for examination of pathology and reproduction), body condition, and milk (for nutritional and contaminant analyses), immune function, and others. Future plans include increasing the numbers of animals at each site and increasing the number of sites evaluated.

In 1995, disease monitoring included serology screening, histopathology, cultures and PCR from stranded, incidentally taken, subsistence or live capture animals. Serology of free ranging harbor seals in southern Puget Sound showed positive antibody titers to Brucella (12 of 62 samples) using three different techniques and also titers to Leptospira (24 of 62 samples). Serology testing for morbillivirus was performed on 306 pinniped and 51 cetacean samples. Of note were two positive results in common dolphins in California. This was the first report of morbillivirus in cetaceans in the north Pacific. One hundred forty animals were evaluated for disease using histopathology or PCR. Of these 109 were cetaceans of 16 species and 31 were pinnipeds of 9 species. Histopathological evidence of 3 infectious diseases not previously reported in the affected marine mammal species were found in stranded animals. There were no histopathologically confirmed cases of morbilli-viral disease.

Bio-monitoring for contaminants and characterizations of previously noted problems were performed. Over 420 tissue samples (blubber, liver, kidney, brain, muscle, heart, melon, fat, blood, milk and stomach contents) from 16 species were collected or analyzed for chlorinated hydrocarbons. An additional 200 samples from 9 species were analyzed for toxic and essential elements. As expected significant differences were found in PCB levels in different species and from different geographic regions. Comparisons of PCB and DDT levels in stranded versus incidental caught common dolphins showed no marked differences. Cadmium levels in bowhead whales were unexpectedly high for a species which feeds at lower trophic levels.

Method development and validation is another key component of the bio-monitoring program. The program supported the development of methods to evaluate methyl sulfones, improve analytical methods of assessing dioxin-like PCBs, improve methods for evaluation of AC-DNA adducts, and increase the sensitivity of rapid chlorinated hydrocarbon measurements.

The archival of tissues for retrospective analyses for contaminants and disease is an important component in biological assessments. The National Marine Mammal Tissue Bank in combination with the Alaska Marine Mammal Archival Project has archived tissues from 168 animals. These include samples (blubber, liver, and kidney) from 89 pinnipeds of 8 species and 79 cetaceans of 5 species. Of these samples, baseline levels of contaminants have been run on 115 tissues. Samples are available to researchers for retrospective studies. The program also has a quality assurance (qa) component. It serves to provide performance comparability for the bio-monitoring and the archiving work. Inter laboratory comparisons are performed to determine the comparability of data. Standard reference materials from marine mammals are being developed. A blubber SRM has been certified and is currently available. A liver SRM is under development.

In summary, the MMHSRP is a multi-agency effort to provide baseline data on health, human interactions and contaminants which may affect marine mammal populations. With such assessments we can be more predictive in our decision making process and more responsive to unusual mortality events. Additionally the program will allow us to evaluate long term trends in population health and begin to look at correlations between anthropogenic factors, population health, and the marine ecosystem.