Juvenile survival, travel time and the in-river environment Presenter: Steve Haeseker CSS Annual Meeting Apr 2 nd 2010
Objectives: Develop models that explain variation in migration time and survival through the hydrosystem Measure and monitor juvenile Chinook and steelhead migration time and survival through the hydrosystem Examine associations between environmental factors and migration time and survival
Monitoring methods: Two reaches: LGR-MCN (CHW, CHH, STH&W) MCN-BON (CHH&W, STH&W) Weekly release cohorts of PIT-tagged fish Estimated median fish travel time (FTT) and survival rate
Environmental and Management Factors: Seasonality (Julian Day) Temperature Turbidity Average percent spill Water travel time (WTT, days)
Water Transit Time (WTT) Estimate of the number of days required for average water particle to transit a reservoir 3 days 2.5 days 8 days
Migration Year WTT Long-term changes in LGR-BON WTT
LGR-MCNMCN-BON Yearling Chinook median travel times
LGR-MCNMCN-BON Yearling Chinook median travel times
LGR-MCNMCN-BON Environmental and management factors: WTT, percent spill, Julian day %88%
Steelhead median travel times LGR-MCNMCN-BON
Steelhead median travel times LGR-MCNMCN-BON
Steelhead median travel times Environmental and management factors: WTT, percent spill, Julian day LGR-MCNMCN-BON %89%
Mid-late April Early May Late May Percent Spill Water Transit Time (days) yearling Chinook travel time (days)
Early May Late May Percent Spill Water Transit Time (days) Mid-late April yearling Chinook travel time (days)
Early May Mid-late May Percent Spill Water Transit Time (days) Mid-late April yearling Chinook travel time (days)
Early May Mid-late May Percent Spill Mid-late April Water Transit Time (days) steelhead travel time (days)
Early May Mid-late May Percent Spill Mid-late April Water Transit Time (days) steelhead travel time (days)
Early May Mid-late May Percent Spill Mid-late April Water Transit Time (days) steelhead travel time (days)
Early May Mid-late May Percent Spill Water Transit Time (days) Mid-late April Percent Spill Chinook steelhead
Early May Mid-late May Percent Spill Unimpounded travel time = 5 to 9 days (Raymond 1979) Mid-late April Percent Spill Chinook steelhead
Mortality approach to survival Mortality = 1 - Survival If daily survival is 0.98, then daily mortality is 0.02 (2%) Survival Migration time (days) 90% 61% 37% If we can predict migration time and daily mortality, then we can predict survival
yearling Chinook mortality rates LGR-MCNMCN-BON
yearling Chinook mortality rates LGR-MCNMCN-BON
yearling Chinook mortality rates LGR-MCNMCN-BON Factors: WTT, Julian dayFactors: Julian day %45%
LGR-MCNMCN-BON steelhead mortality rates
LGR-MCNMCN-BON steelhead mortality rates
LGR-MCNMCN-BON Factors: WTT, Julian day, spillFactors: temperature steelhead mortality rates %51%
Mid-late April Mid-late May Early May yearling Chinook daily mortality Water Transit Time (days)
Early May Mid-late May Percent Spill Water Transit Time (days) Mid-late April steelhead daily mortality
Early May Mid-late May Percent Spill Water Transit Time (days) Mid-late April steelhead daily mortality
Early May Mid-late May Percent Spill Water Transit Time (days) Mid-late April steelhead daily mortality
Yearling Chinook survival LGR-MCNMCN-BON Outmigration year
Yearling Chinook survival LGR-MCNMCN-BON Outmigration year
Yearling Chinook survival LGR-MCNMCN-BON % 38% Outmigration year
LGR-MCNMCN-BON steelhead survival Outmigration year
LGR-MCNMCN-BON steelhead survival Outmigration year
LGR-MCNMCN-BON steelhead survival % 70% Outmigration year
Early May Mid-late May Percent Spill Water Transit Time (days) Mid-late April Yearling Chinook survival
Early May Mid-late May Percent Spill Water Transit Time (days) Mid-late April Steelhead survival
Percent Spill Water Transit Time (days) Early May Mid-late May Percent Spill Mid-late April
Percent Spill Early May Mid-late May Percent Spill Mid-late April Unimpounded Chinook survival = ~ 0.89 (Raymond 1979)
Travel time is related to river velocity: the higher the water velocity, the higher the rate of fish migration. Impounding the river reduced the river velocity and migration rate of both juvenile Chinook salmon and steelheads to one- third that through free-flowing stretches of river. Prior to construction of new dams (1966 to 1968), survival of wild Chinook salmon from the Salmon River to Ice Harbor Dam averaged 89% (range 85 to 95%). Following completion of Lower Monumental and Little Goose Dams (1970), average survival to Ice Harbor Dam sharply declined to 33% (range 12 to 50%). 31 years ago… -Raymond (1979)
Conclusions Juvenile travel times, mortality rates and survival rates through the hydrosystem are strongly influenced by managed river conditions (water transit time and spill levels). Statistical relationships accurately predict the effects of environmental factors and management strategies on migration and survival rates of juvenile yearling Chinook and steelhead. Improvements in in-river survival and travel times can be achieved through reductions in water transit time or increased spill.