A life history framework to understand production of juvenile steelhead in freshwater applied to the John Day River, Oregon Jason Dunham, USGS Forest and Rangeland Ecosystem Science Center John McMillan, Department of Fisheries and Wildlife, OSU - MS Justin Mills, Department of Fisheries and Wildlife, OSU - MS Matt Sloat, Department of Fisheries and Wildlife, OSU – Ph.D. (new) Gordie Reeves, US Forest Service Pacific Northwest Research Station Chris Jordan, National Marine Fisheries Service, Northwest Fisheries Science Center

John Day River Major tributary to mid-Columbia River No large dams (but downstream in Columbia) No hatcheries (but hatchery “strays” present) Mix of listed “steelhead” and non-listed “rainbow trout” present Broad-scale environmental variability

Major reasons for listing steelhead as a threatened species in the Mid-Columbia Declines in abundance of wild populations Present abundance <<< historical Hatchery influences + uncertainty Habitat alteration Lack of information regarding interactions between resident rainbow trout and anadromous steelhead Busby et al. 1996; NMFS 1999

Three Questions Why “steelhead” and “rainbow” trout? How do we tell them apart? What do we do about it?

Why “steelhead” and “rainbow” trout? Variation in migration behavior –Growth and survival tradeoffs –How to make it to maturity? Jonsson and Jonsson 1993; Hendry et al. 2004

Why “steelhead” and “rainbow” trout? Variation in migration behavior –Growth and survival tradeoffs –How to make it to maturity? Influence of sex –Once mature how to maximize fitness? –Different sexes = different problems Males – mate with females Females – fecundity Jonsson and Jonsson 1993; Hendry et al. 2004

Sex and mating tactics (e.g., Gross 1991) Mating tacticHabitat useHabitat use

Common mating patterns Mating tacticHabitat useHabitat use

Why do we care about “rainbows?” Long-term viability and life history diversity Interbreeding of “steelhead” and “rainbows” –Increased Ne of O. mykiss

Why do we care about “rainbows?” Long-term viability and life history diversity Interbreeding of “steelhead” and “rainbows” –Increased Ne of O. mykiss Flexible expression of life history possible –Spreading risk across habitats –Buffer periods of low survival in FW or marine

How do we tell them apart? 1. Use of neutral genetic markers Genetic differences among different life histories within the same basin are generally less than differences among basins (McPhee et al. 2007).

How do we tell them apart? 1. Use of neutral genetic markers Genetic differences among different life histories within the same basin are generally less than differences among basins (McPhee et al. 2007). Difficult to isolate “life history” from other confounded factors that lead to genetic isolation –Isolation by distance or habitat type –Isolation by timing of reproduction –Episodic gene flow

How do we tell them apart? 1. Use of neutral genetic markers Genetic differences among different life histories within the same basin are generally less than differences among basins (McPhee et al. 2007). Difficult to isolate “life history” from other confounded factors that lead to genetic isolation –Isolation by distance or habitat type –Isolation by timing of reproduction –Episodic gene flow Difficult to ID what a “rainbow trout” or “steelhead” is in your sample (esp. males)

2. Direct observation Mating behavior in the field –Spatial and temporal isolation »Zimmerman and Reeves, McMillan 2007 How do we tell them apart?

2. Direct observation Mating behavior in the field –Spatial and temporal isolation »Zimmerman and Reeves, McMillan 2007 Otolith microchemistry –Sr/Ca ratios (higher in seawater) »Zimmerman et al. How do we tell them apart?

2. Direct observation Mating behavior in the field –Spatial and temporal isolation »Zimmerman and Reeves, McMillan 2007 Otolith microchemistry –Sr/Ca ratios (higher in seawater) »Zimmerman et al. Examination of maturity –Mature female in freshwater ≠ steelhead –Mature male in freshwater…? How do we tell them apart?

Two studies in the John Day River Spatial distribution of anadromous females (Justin Mills, MS) –Indirectly inferred from juveniles (0+, 1+) –Chemistry of otolith primordium Spatial distribution of mature individuals (John McMillan, MS) –Males –Females

Two studies in the John Day River Spatial distribution of anadromous females (Justin Mills, MS) ODFW EMAP sites –Spatial patterns –Landscape influences Water temperature Water chemistry Network position Channel morphology Flow regime/discharge Barriers

Two studies in the John Day River Spatial distribution of mature individuals (John McMillan, MS) –Maturation of age 1+ males Individual condition –Body size –Prior year growth –Lipid % –Individual condition Water temperature Population density of O. mykiss Alkalinity/conductivity

What do we do about it? Life history expression –A “filter” for production of anadromous O. mykiss Filter can be applied in two ways: –Manage by location (=static processes) –Manage processes that influence life history expression (=dynamic processes)

Natural Processes Human Influences Bio-physical Environment Abundance Productivity Processes influencing life histories Steelhead juvenile production Natural Processes Human Influences Bio-physical Environment Abundance Productivity Locations with different proportions of anadromy Steelhead juvenile production Freshwater resident production

Assumptions Location: P anad = Constant (static processes) –Genetic (e.g., high heritability of anadromy) –Related to “immutable” environmental influences –Management constrained to locations with potential

Assumptions Location: P anad = Constant (static processes) –Genetic (e.g., high heritability of anadromy) –Related to “immutable” environmental influences –Management constrained to locations with potential Process: P anad = Variable processes –Flexible expression – phenotypic plasticity Variability in males > females –Related to variable environmental influences –Some of above can be influenced by management

Examples Location –Intrinsic potential (Burnett et al. 2007) –Influence of groundwater (Zimmerman and Reeves)

Examples Location –Intrinsic potential (Burnett et al. 2007) –Influence of groundwater (Zimmerman and Reeves) Process –Barriers: anadromous  resident –Emergence of anadromy from residents –Short term changes in life history related to changes in temperature (Dunham et al. unpubl)

ImmatureMature maleMature female 0% 20% 40% 60% 80% 100% Age 0+ Occurrence UB 30 BR 36 BD 72 Age 1+ UB 106 BR 53 BD 57 Age 2+ UB 19 BR 8 BD 8 Cool Warm

Modeling approach Deal explicitly with life history expression in O. mykiss Be spatially explicit Provide multi-scale context (site versus stream network) Integrate physical and biological processes

Modeling approach Deal explicitly with life history expression in O. mykiss Be spatially explicit Provide multi-scale context (site versus stream network) Integrate physical and biological processes Inform on-the-ground decisions Relate to specific management actions Be easily manipulated to evaluate alternative scenarios

Modeling approach Inform on-the-ground decisions Relate to specific management actions Be easily manipulated to evaluate alternative scenarios Be flexible in using different sources of information Deal explicitly with uncertainty Easy to understand with transparent assumptions

Expected outcomes A better understanding of complex relationships influencing production of juvenile steelhead in freshwater. Identify major uncertainties. Testable hypotheses about management alternatives  monitoring and evaluation. A straightforward management framework and tool that can be applied to inland steelhead in general.

Timelines Model of anadromy – 2008/09 Freshwater maturation /09 Model of freshwater productivity – 2011 Ph.D. dissertation

North Fork John Day River 2006: John McMillan photo Questions - Discussion

RESIDENT FISH MIGRATION RESIDENT FISH DISPERSAL HOMING Migration behavior: habitat use, dispersal, “straying” “STRAY”