It is widely assumed that salmon need cool, clean water in adequate supply to survive and reproduce in Pacific Northwest watersheds. Accordingly, there has been a considerable effort in recent years to understand the biological significance of temperature and flow as limiting factors for salmon conservation and recovery. Much less attention has been given to water quality, with the exception a few conventional parameters such as dissolved oxygen, sediment, and nutrients. As we look to the future, however, the chemical landscape is becoming increasingly more complex and dynamic, particularly with the development of lowland coastal watersheds throughout the region. Non-point source pollution (typically via stormwater runoff) is now the leading cause of degraded water quality in mixed-use watersheds. Current-use pesticides, heavy metals, petroleum hydrocarbons, and other contaminants are commonly discharged into rivers, lakes, and estuaries. The impacts of these chemical stressors on native aquatic species, including salmon, are very poorly understood. This presentation will highlight specific examples of ongoing research in this area, with an emphasis on ecological realism, the vulnerability of sensitive life-history stages, and the importance of functional linkages across different scales of biological organization.
Nat Scholz is a Research Zoologist at the NOAA Fisheries' Northwest Fisheries Science Center in Seattle. He grew up exploring the beaches and tidepools of the central Oregon coast and went on to study marine biology in college. He earned a Masters degree from the Boston University Marine Program in Woods Hole and a PhD in Zoology from the University of Washington. He then began working on endangered species issues as a postdoctoral associate with the National Research Council (National Academies of Science and Engineering). Since 1999, he has been the lead investigator of a research team in the Ecotoxicology and Environmental Fish Health Program. The team works on wide ranging problems of human land use, chemical habitat quality, and the conservation of native fish species in the Pacific Northwest. Current studies range from the genetic manipulation of cardiovascular function in fish embryos to forensic investigations of salmon die-offs in urban streams.