Application of a Method for Assessing the Impact of Watershed Practices: Effects of Logging on Salmonid Standing Crops

Abstract Preliminary studies on three control streams (unaffected by logging) indicated that there were no significant intrastream differences in the total biomass of Atlantic salmon (Salmo salar), brown trout (Salmo trutta), and brook trout (Salvelinus fontinalis) between discrete areas of similar habitat. Therefore, total salmonid biomass should be a good indicator of stream habitat quality for salmonids and useful in assessing the impacts of watershed practices. Total salmonid biomass was used to assess the effect of logging disturbances, including stream crossings, clear-cuts, and bank modification, on the salmonid populations of 10 streams in New Brunswick and Nova Scotia. This biomass was measured at pairs of logging-disturbed and upstream control areas of the 10 streams. Salmonid biomass decreased significantly downstream of two stream crossings, probably because of increased siltation, while seven clear-cuts and one bank modification along the other eight streams had no significant effect on salmo...