Relationships among parasites and pathologies in sentinel bivalves:NOAA status and trends `Mussel watch' Program

摘要

NOAA's National Status and Trends `Mussel Watch' Program includes a comprehensive survey of the histopathology of sentinel bivalves from the East, West, Gulf, and Great Lakes coasts of the United States. We analyzed the data for 1995-1998 to identify relationships between various parasites, various pathologies, and between parasite/pathology pairs with the goal of identifying consistencies and differences in these relationships between sentinel bivalves and between major geographic units of the U.S. coastline. The prevalences of parasite, pathology, and parasite-pathology pairs were significantly correlated more frequently for oysters than for mussels. The number of significant correlations within Gulf-coast oysters exceeded the number within East-coast oysters. Correlations were least frequent among East-coast mussels. The incidence of significant negative correlations in prevalence far exceeded the incidence of significant positive correlations in all species and bay regions. Significant relationships in infection intensity occurred much less frequently than for prevalence. Positive correlations occurred more frequently than they did for prevalence. Both trends reinforce the belief that environmental factors controlling transmission are likely distinctive from those controlling proliferation. Only a few relationships between parasites were common to more than one sentinel bivalve or more than one coastal region. Not a single common relationship involved a pathology. However, though commonalities were few, consistent trends in prevalence between mussels and oysters and between coastal regions suggest potentially important large-scale trends among some important parasite groups, particularly the gregarines and gut cili-ates, gill gregarines and cestodes, prokaryotic inclusions and trematode metacercariae, and Perkinsus marinus and the gregarines.