348 
Fishery Bulletin 1 13(3) 
Month 
Figure 5 
Sacramento River winter Chinook salmon (Oncorhynchus tshawytscha ) contact rates per unit of effort 
for the (A) commercial and (B) recreational sectors in the San Francisco (SF) management area and for 
the (C) commercial and (D) recreational sectors in the Monterey (MO) management area. Circles denote 
estimated values for individual years, triangles indicate mean values, and squares denote median values. 
The methods used to infer mean and median contact rates per unit of effort for the recreational sector 
in February and March are described in the text. 
degree of fishery exploitation experienced by SRWC in 
earlier years. These impact-rate hindcasts were used to 
extend the SRWC stock assessment and have contrib- 
uted important fishing mortality inputs to a life-cycle 
model for this population (Hendrix et al., 2014). More 
generally, an extended time series of fishing mortality 
rates derived with the methods described here could 
allow for an extended reconstruction of recruit abun- 
dance useful for stock-recruit analysis (PSC 10 ). 
10 PSC (Pacific Salmon Commission). 1999. Maximum sus- 
tained yield or biologically based escapement goals for se- 
lected Chinook salmon stocks used by the Pacific Salmon 
Commission’s Chinook Technical Committee for escapement 
assessment, vol. 1. Pacific Salmon Comm. Joint Chinook 
The impact-rate estimates derived from cohort re- 
construction for 2000-2012 reflect many layers of 
salmon fishery regulations. In particular, ocean fish- 
eries in California frequently have been constrained 
by conservation concerns and ocean-versus-river fish- 
ery allocations for Klamath River fall Chinook salm- 
on (Prager and Mohr, 2001). A collapse of the SRFC 
stock (Lindley et ah, 2009) closed nearly all California 
ocean salmon fisheries in 2008 and 2009 and heavily 
constrained fisheries in 2010. The first SRWC-specific 
constraints to fisheries began after the species was list- 
Tech. Comm. Rep. TCCHINOOK (99)-3, 104 p. [Available at 
website.] 
