The only remaining self-sustaining native population of lacustrine Lahontan cutthroat trout (Oncorhynchus clarki henshawi) not affected by nonnative salmonids is in Summit Lake, Humboldt County, Nevada. Annual spawning runs in 1993 and 1994 were monitored at a fish trap on Mahogany Creek, the only spawning tributary for Summit Lake. Number of spawners was similar in both years, with 1290 upstream migrants observed in 1993 and 1255 in 1994. In 1993, 137 postspawners (10.6% of upstream migrants) returned to the lake, and in 1994, 434 postspawners (34.6% of upstream migrants) returned downstream through the fish trap. Two distinct groups of subadult Lahontan cutthroat trout were observed moving downstream in 1994. The first group passed downstream between 27 April and 29 July and included 1188 fish (average fork length = 90 mm). Between 1 August and 31 October, 1160 fish (average fork length = 42 mm) moved downstream. Size differences of these 2 groups suggest that the 1st group comprised fish that had overwintered in Mahogany Creek, while the 2nd group were probably young-of-the-year.
Vinyard, Gary L. and Winzeler, Alice
"Lahontan cutthroat trout (Oncorhynchus clarki henshawi) spawning and downstream migration of juveniles into Summit Lake, Nevada,"
Western North American Naturalist: Vol. 60
, Article 10.
Available at: http://scholarsarchive.byu.edu/wnan/vol60/iss3/10