Dunham Creek declined from 1 1 redds in 2002 to 6 in 2003. 

 Gold Creek in 2003, down from six a year earlier. 



We counted four redds in 



Bull trout spawning area temperature study 



Bull trout spawning occurs at discrete locations, which coincide with water 

 temperature regimes typically influenced by groundwater inputs, a source that moderates 

 temperatures throughout the entire year. The influence of groundwater upwelling on bull 

 trout incubation temperatures has not been well quantified (MBTSG 1998), although is 

 important because it influences embryo survival, development and timing of emergence 

 (Weaver and Fraley 1991). To determine water temperatures in critical bull trout 

 spawning areas during the winter months, temperature data was collected in Gold Creek, 

 Monture Creek, Copper Creek and Cottonwood Creek in 200 1 -02 at current or presumed 

 historic spawning locations (Table 10). In order to compare temperatures in upstream 

 (spawning) with downstream 



Table 10. Winter water temperature summaries for 

 six streams influenced by groundwater 



(non-spawning) reaches, 



temperature data was also 

 collected in each of these 

 streams close to the mouth, 

 downstream of spawning 

 locations. Kleinschmidt and 

 Nevada Spring Creeks were 

 also monitored during the 

 winter months of 200 1 . These 

 two streams were historical 

 bull trout spawning sites based 

 on local accounts. 



Temperatures were collected 

 at these suspected historical 

 sites to see how winter 

 thermal regimes compare to 

 current bull trout spawning 

 sites. 



Temperature results 

 from Gold, Monture, Copper, 

 and Cottonwood Creeks in 

 2002 revealed that upstream 

 spawning locations were significantly warmer during mid-winter months as compared 

 with downstream, non-spawning locations (Paired t-test, P < 0.05). Temperatures in 

 upstream spawning reaches are very important to bull trout populations wintering in these 

 areas as the formation of anchor ice (which induces stress) is inhibited, while conditions 

 in downstream locations were shown to be less ideal. For example, Monture Creek, the 

 most stable of all bull trout streams in terms of successful reproduction, maintained the 

 highest winter temperature and lowest range of water temperature fluctuations of the 

 current spawning sites. Downstream locations on all non-spawning locations had 



80 



