Coastal Cutthroat Trout as Sentinels of Lower Mainland Watershed ...

50years owing to operational constraints during winter floods. Counts of adult cutthroataveraged 42 from 1983 to 1985 and ranged from 37-45. Of note, adult steelhead havedeclined 65 % over the twenty years, from an average of 220 in the 1980s to an averageof 75 over the past decade (Figure 17). At another Fraser tributary, Kanaka Creek, aPetersen population estimate of wild cutthroat adults was made in 1987/88, which was116 wild adults (15/km) and 118 hatchery adults, based on a total of 87 enumeratedadults (Murdoch 1988). Estimates were not undertaken in recent years; thus, an updatedpopulation would be instructive.Little Campbell River Steelhead - Fence Counts (1982 - 2004)500HatcheryWild400300# Steelhead20010001982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004DateFigure 17. Counts of wild and hatchery adult steelhead trout at Little Campbell Rivercounting fence from 1982 (a partial year) to 2004 (data from Semiahmoo Rod and GunClub, summarized by A. Hanson, BCCF).More recently, annual counts of cutthroat smolts have been made since 1998 at theSalmon River. Downstream migrant fish have been enumerated (as a coho index stream)for several years by the federal Department of Fisheries and Oceans, assisted on troutcounts and sampling since 1998 by the BC Conservation Foundation. Although thesecutthroat smolt counts are not adjusted for trapping efficiency, they do provide usefultrend data. From 1998 to 2004, annual cutthroat smolt yields have decreased by about47% from 1,500 smolts to about 800 smolts, with a low of approximately 200 smolts(decrease of approximately 87%) in 2003 (Figure 18). A preliminary 2005 cutthroatsmolt count suggests that approximately 1,100 smolts will outmigrate this year, which isan improvement from the 800 smolts enumerated in 2004. In comparison, steelheadsmolt yields at Salmon River have been variable ranging from about 1,000 to 4,600 withan uncertain trend.DeLeeuw and Stuart (1982) estimated a population of 6,260 1+ cutthroat parr in theSalmon River in 1979 which can be used to estimate the cutthroat smolt yield in 1980.