They also eat birds, bats and insects. When old growth forests are logged, the very old and very large trees the Northern Spotted Owl depends on are destroyed. This loss of prime habitat is the main reason for their decline. Northern Spotted Owls were listed as threatened in 1990. Shrimps, crabs, and crayfish are crustaceans.
Plankton is used as food by fish.
The National Estuary Program was established in 1987 in amendments to the Federal Clean Water Act. The program is designed to protect estuaries of national significance that are threatened by degradation caused by human activity. It provides a framework and resources for local communities to come together to define problems and identify ways to address them. The lower Columbia River estuary became part of the national program in 1995. The mission of the Lower Columbia River Estuary Program is to preserve and enhance the water quality of the estuary and to support its biological and human communities.