Outside Influences

Climate change
In the Pacific Northwest, global climate change models indicate that winter and summer temperatures in the region are likely to be warmer, with possibly higher amounts of winter precipitation. These climate changes may result in changes in the temperature of both Walsh Lake and Webster Creek, which could affect not only kokanee directly, but also could cause changes in their prey base. Increased temperatures in Walsh Lake may alter interactions with non-native species such as largemouth bass and yellow perch that are more tolerant of warm water conditions. The frequency and intensity of winter flooding may also increase. Because high flow events can cause scouring of the stream bed, they can result in high levels of mortality to kokanee early life history stages (eggs and alevins).

More information on the status of global climate change can be found on the US Global Change Research Program website.

Low genetic diversity
The DNA analysis revealed that the kokanee samples collected from a single spawning run in Webster Creek had low genetic diversity. Genetic diversity plays a large role in a species ability to adapt to changing environments. A species with a large degree of genetic diversity will have more variations from which to choose the most appropriate alleles. For example, if the Walsh Lake kokanee are exposed to a new disease, they may not have the genes for resistance to that disease that other populations with greater genetic diversity might possess.