Sa. Mullner et al., Visually estimating substrate composition at potential spawning sites for trout in mountain streams, J FRESHW EC, 15(2), 2000, pp. 199-207
Self-sustaining trout populations in mountain streams depend on the presenc
e of suitable spawning habitat. However, current watershed-scale habitat in
ventory techniques do not assess trout spawning habitat. A spawning substra
te evaluation technique is a logical component of such inventories because
it would provide data on spatial patterns of suitable substrate across wate
rsheds. We evaluated a visual technique designed to assess substrate suitab
ility for trout spawning. Comparisons of visual assessments of potential sp
awning sites to those using a single-probe freeze-core were made. The visua
l method of evaluating spawning substrate was nearly as good as the freeze-
core method. Considering the time, labor, and cost efficiency of visual sub
strate assessment, this visual technique is a reasonable alternative when e
valuating trout spawning substrate at the watershed scale.