There has been a lot of improvement in Prince William Sound, but the ecosystem has a long way to go before it returns to normal. An ecosystem is made up of the plants and animals that live in an area. Each living thing in the ecosystem depends on other living things. That means when the fish die, there is less food for the seals that eat them. As the seals die, there is less food for the orcas that eat seals.
Humans also play a role in the ecosystem.
Some people in Alaska still depend on seal meat for food. Fishing is also a source of income for the people there. As the seals and fish struggle to survive, so do the people who depend on them. More than ten years later, some good has come from the spill of the Exxon Valdez, though it was a terrible accident. The government has bought 650,000 acres of land to protect the animals that live there.