Salish Sea Currents Series

Disease as an ecological force

A main story and two vignettes on impacts of disease in the ecosystem. Sponsored by U.S. EPA.

In the third series of Salish Sea Currents, we present a main story and two vignettes on impacts of disease in the ecosystem. [View printable PDF of this series]


Pacific herring have long been considered an essential part of the Puget Sound food web. Now, studies are beginning to reveal how diseases in herring could be reverberating through the ecosystem, affecting creatures large and small. We continue our coverage of the ecological impacts of disease in Puget Sound with this look at the region's most well-known forage fish.

Chinook, coho and steelhead populations in Puget Sound have declined dramatically over the past 30 years. In some cases, counts of fish returning to the rivers are just a tenth what they were in the 1980s. While many possible causes of this decline are under consideration, some researchers are focusing on the combined effects of predators and disease. This article continues our coverage of the ecological impacts of disease in Puget Sound.

From orcas to starfish to humans, disease affects every living creature in the ecosystem. Scientists are increasingly alarmed by its potential to devastate already compromised populations of species in Puget Sound.