Interest in the health of marine mammals has grown with the increase in
unexplained mortalities and strandings of coastal species. Investing time and resources into
exploring the causes behind these incidents is justifiable in that we have such an enormous
influence on the environment in which these animals live; perhaps our impact is responsible for
these occurrences, in which case, we must direct our energy into both preventing contaminating
circumstances and regenerating the habitability of coastal regions.
Thus far, direct correlations between exposure to pollutants and its effect
on the immune systems of marine mammals have not been made. The consequences of exposure could
be either immunosuppressive or immuno-enhancing. Regarding the former, cases in which pathogenic
agents have been isolated from mortalities or from stranded animals may simply represent
opportunistic infections; however, increased sensitivity to pathogens could be the result of
immunosuppression stemming from contaminant exposure. In addition, no one has addressed the
latter possibility of immuno enhancement; autoimmune or hypersensitivity reactions can, indeed,
result from toxin exposure, as has been shown in terrestrial animals. Before we can demonstrate
any association between pollutant exposure and immune abnormalities in marine mammals, we
absolutely must acquire a basic understanding of the immune systems of the various coastal
species.
We have been engaged in establishing an extensive panel of reagents and
techniques for the comprehensive assessment of immunologic health of harbor seals (phoca
vitulina) and for the establishment of baseline values for the species. Such tools and data
will be used to define potential associations between acute and/or chronic exposure to petroleum
products, as well as other chemical pollutants, and immune system dysfunction. This type of
study is most appropriate as harbor seals occupy coastal waters and thus are at considerable
risk of exposure to chemical pollutants.