Groundwater Habitat Interactions for Interior Fraser Coho

There is a lack of knowledge related to what constitutes critical habitats for Interior Fraser (IFR) coho (Bailey et. al., 2004), and little study into the relationship between groundwater and habitat use by juvenile IFR coho. The majority of conducted studies have focused on linking adult redd selection to groundwater, and have been done on coastal US streams. This was the third year of a study to confirm juvenile IFR coho usage of groundwater upwelling areas as thermal refuge from lethal mainstem summer water temperatures. Sites were monitored for fish presence/absence and behavior, and water temperatures recorded through the duration of the study. Rather than focusing on one stream, two First Nations groups, in collaboration with Fisheries and Oceans Canada (DFO), are continuing to sample four tributaries of the Fraser River (Thompson River Basin), allowing for better representation and more solid/robust results. Objectives for 2009/2010 were:

1. Locate new groundwater upwelling areas in the Nicola watershed (NTA),

2. Determine the presence/absence of seasonal and diel spatial distribution patterns of juvenile IFR coho, and its relationship to groundwater upwelling sites in tributaries of the Interior Fraser Basin,

3. To provide a third year of information that will be the basis for developing strategies to protect and enhance groundwater influenced coho habitat, and improve groundwater management and IFR coho conservation, and

4. To establish a coordinated, science-based approach between First Nations and government agencies.

Results for 2009/2010 are:

• The NTA located two new mainstem groundwater upwelling sites (NR32.6 and CW9.42),

• Water temperature data were recorded for groundwater and control sites (July to October),

• Fish usage by species and behaviors recorded before, during and after peak stream temperatures,

• The study showed that groundwater upwelling in mainstem rivers/streams provide critical habitat during summertime peak stream temperatures.