To study how Prince William Sound is recovering from the Exxon Valdez oil spill, NOAA conducted a monitoring program from 1990 (the year after the spill) through 2000. We chose about 20 study sites around the Sound, including (1) sites that had been oiled by the spill but not cleaned up, (2) sites that had been oiled and cleaned, and (3) sites that were not oiled.

Each year during the monitoring, we visited each site to measure the numbers and kinds of species of intertidal plants and animals found there. We used these observations to track changes in the biological communities over time.

In 1999, we began a smaller-scale, experimental phase of our research, focusing our work on selected sites in order to better understand the ecological recovery process from an oil spill of this type. These experimental studies are ongoing and continue to yield insights into oil and cleanup effects.

We will use this information to augment and improve the technical basis for oil spill response and cleanup in the future, with an overall goal of minimizing environmental harm.