Effects of forestry roads on reproductive habitat and exploitation of laketrout (Salvelinus namaycush) in three experimental lakes

This study was designed to test the effects of two potential impacts of for est access roads on lake trout (Salvelinus namaycush) lakes in the Boreal S hield ecozone: (i) loss of reproductive habitat through siltation and (ii) increased access and exploitation. During an 9-year study (1991-1999) in Wh itepine Lake, access to seven original spawning sites and over 250 alternat e spawning sites was progressively removed by covering the substrate with o paque plastic sheeting to simulate siltation. No effects on recruitment of lake trout have yet been detected. Mark-recapture estimates of juvenile (<3 70 mm fork length) abundance remained high, mean body size did not increase , and emergent alevins continued to be produced from the alternate spawning sites each year. Similar results occurred in a short-term study in Helen L ake. The lack of obvious effects of reproductive habitat loss was in sharp contrast with the rapid and severe effects that fishing pressure exerted on the lake trout population in Michaud Lake where access was improved by con struction of a 12-km forest access road. These findings suggest that lake t rout can tolerate substantial losses in spawning habitat, but natural popul ations, particularly in small lakes, must be protected from excessive explo itation.