Table 5. Examples of potential covariates for analysis of coho salmon productivity in the Hood Canal IMW. Hypothesis Metric Life-stage Effect on Mechanism productivity Spatial distribution of Spawning Positive Greater dispersal alleviates spawning adults density dependence Number of days flow > Egg Positive Higher flows permit adult median during incubation deposition dispersal period Sept 1 Jan 15 – Number of days flow > Egg to parr Negative High flows scour redds bankfull during incubation period Nov 1 Feb 28 – Geographic extent of Parr to smolt Positive Subsurface flow restricts wetted habitat (km) connectivity, limits habitat during summer (July availability and magnifies – Aug) density dependence Number of days flow > Parr to smolt Negative High flows during winter bankfull during overwinter reduce juvenile overwinter overwinter period Oct 15 survival and flush fish out Feb 28 of system – Pool frequency Parr to smolt Positive Pools provide refuge from overwinter high flows Habitat complexity: Egg to smolt Positive Complex habitats promote variance in stream width productive populations to ratio
Table 5. Examples of potential covariates for analysis of coho salmon productivity in the Hood Canal IMW. Hypothesis Metric Life-stage Effect on productivity Mechanism Spatial distribution of spawning adults Spawning Positive Greater dispersal alleviates density dependence Number of days flow > median during incubation period Sept 1 – Jan 15 Egg deposition Positive Higher flows permit adult dispersal Number of days flow > bankfull during incubation period Nov 1 – Feb 28 Egg to parr Negative High flows scour redds Geographic extent of wetted habitat (km) during summer (July – Aug) Parr to smolt Positive Subsurface flow restricts connectivity, limits habitat availability and magnifies density dependence Number of days flow > bankfull during overwinter period Oct 15 – Feb 28 Parr to smolt overwinter Negative High flows during winter reduce juvenile overwinter survival and flush fish out of system Pool frequency Parr to smolt overwinter Positive Pools provide refuge from high flows Habitat complexity: variance in stream width to ratio Egg to smolt Positive Complex habitats promote productive populations