Fig. 4.

Observed values (closed triangles), predicted values (open circles), and P values for the two multiple linear regressions of pink salmon production [generational survival; ln (R_{t − 2}/S_t)]. (i) For 2001–2009 data, the relationship of generational survival to farm-source adult female L. salmonis sea lice was not significant (A), but the relationship of generational survival to parental escapement (S_{t − 2}) was significant (C). (ii) For 1991–2009 data, the relationship of generational survival to farm fish production was not significant (B), but the relationship of generational survival to parental escapement was significant (D). Dotted lines denote where returns equal parental escapement. For emphasis, solid trend lines are shown for significant relationships (C and D).