Fraser River Sockeye Fisheries and Fisheries Management - Cohen ...

Escapement6,000,0005,000,0004,000,0003,000,0002,000,000SummersEscapement4yr avgInterim TRPInterim LRP1,000,00001960196419681972197619801984198819921996200020042008Figure 18 Escapement and operational reference points for Summer-run sockeye.The Summer-run timing group includes four stocks: Chilko, Quesnel, LateStuart, and Stellako. Quesnel and Late Stuart follow a pronounced 4-yearcyclic pattern.The 4-year average escapement for Summer-run sockeye has been consistently above theLEB since 1980 (Figure 18). The annual total escapement for the Summer-run droppedbelow the LEB once in the past 10 years (2004), when in-river migratory conditionsresulted in substantial mortalities between Mission and the spawning grounds. From2007-2009, when escapements approached the LEB, commercial fisheries were notpermitted and First Nation fisheries for FSC purposes were substantially reduced. TheSummer-run sockeye includes four indicator stocks with defined LEBs. These LEBswere compared with the historical escapement estimates for these stocks and confirmedthat the 4-year moving averages of the annual escapement estimates have consistentlyexceeded the LEBs for each of the Summer-run indicator stocks since the early 1980s.The 4-year average escapement for Late-run sockeye has been consistently above theLEB since 1970 (Figure 19). The LEB and 4-year average values are heavily influencedby the dominant cycle line, where run size can be 4000-fold larger than those observed inoff-cycle years (e.g., Adams River run was estimated to be ~1,700 in 1989 and ~7M in1990). Consequently, the annual total escapement for this run-timing group is usuallysubstantially above the LEB in dominant cycle years (e.g., 2002), close to the LEB in108