Between 1985 and 1996, there was little change in contaminant levels found in mussels and oysters, organisms that can concentrate contaminants found in water. Pesticides and other contaminants were detected in more than half of coastal sediments surveyed from 1990 to 1996, in all regions of the country, but rarely in concentrations that exceed levels associated with potential biological impacts. Some groups of species are important because they play key ecological roles, whereas others are important because they are powerful indicators of disturbance to the ecosystem. We are developing a measure or set of measures for the condition of key species groups in each of several key habitat types. For the final report we will select and further refine these measures and collect additional data.
Seabird populations are key indicators of ecosystem integrity.
However, population trends are unknown for nearly 50 percent of Alaskan species and more than 25 percent of East Coast species. One-third of the 300 stocks whose status is known are either overfished or approaching an overfished condition. Finally, case studies indicate that the rates of introduction of nonnative species and the occurrence of fish abnormalities and harmful algal blooms are increasing. However, there are no consistent and comprehensive national data that can validate these concerns. The table on the next page provides a listing of the measures presented in greater detail on the following pages.