Quantifying Genetic Diversity Steelhead Stocks Eric Parkinson, Art Tautz, Bob Hooton BC Min. Water, Land & Air Protection Photo: E. Keeley

~70 spp. B.C. 950,000 km 2 Tennessee 110,000 km 2 Geographic area and the number of native species of Freshwater Fish ~250 spp. Why care about genetic diversity: BC has very few species but lots of Intraspecific diversity

Post-Glacial Dispersal Routes Bering Refuge Queen Charlotte Refuge Columbia RefugeCoastal Refuge Missouri Refuge Edge of Ice Sheet Why so few species?

Geoclimatic diversity results in local adaption Ecozones of BC Why so much intraspecific diversity?

Fish Species at Risk in B.C. Three Directions 1. Systematic assessment of all species 2. Focal studies on specific species that are judged to be most at risk 3. Identify populations representing rare or endangered ecotypes within each species

1:50,000 Lakes and Streams (i.e. Lakes >1 ha) Digital BC Watershed Atlas Linked to info on: Stream length, size, gradient, flow, lake influence, species records, land use, stocking records, terrain maps, geology etc. for 20,000 3 rd order & greater watersheds

Steelhead Distribution in BC Out of Range Rainbow Trout Steelhead

Steelhead Stock Structure n The smallest independent unit – stock = VSP? –Genetically isolated –Large enough to be viable n Genetic Groups of Stocks share: –Major Phylogenetic Associations = ESU? –Adaptation to a common environment = Strata? n Management Groups have similar: –Exploitation rates, hatchery influence, management goals –Can cut across genetic groups

Steelhead Stock Structure n The smallest independent unit – stock = VSP? –Genetically isolated –Large enough to be viable n Genetic Groups of Stocks share: –Major Phylogenetic Associations = ESU? –Adaptation to a common environment = Strata? n Management Groups have similar: –Exploitation rates, hatchery influence, management goals –Can cut across genetic groups

Steelhead Stock Structure n The smallest independent unit – stock = VSP? –Genetically isolated –Large enough to be viable n Genetic Groups of Stocks share: –Major Phylogenetic Associations = ESU? –Adaptation to a common environment = Strata? n Management Groups have similar: –Exploitation rates, hatchery influence, management goals –Can cut across genetic groups

Chehalis R. Weaver Cr. Examples of adaptive and molecular differences among Steelhead in adjacent streams Rule: Every watershed that empties into either the ocean or a large river contains a stock LDH and MDH Allozyme Frequencies Stock Structure is quantified using data on genetic and phenotypic differences

Exclude Very Small Watersheds “Viable Salmonid Population” n Use various measures of size –Stream order and magnitude –Watershed area –Length of anadromous stream n Goal is a Viable Population –Run size > 20 – 5 yr generation gives > 100 –N e > 30?

Defining Steelhead Population Structure Size, location, and drainage links come from the Watershed Atlas Find all independent stocks Eliminate very small streams Review by Regional Biologists ~ 630 viable steelhead stocks in~ 580 BC streams

Most steelhead stocks are in small watersheds

Steelhead Stock Structure n The smallest independent unit – stock = VSP? –Genetically isolated –Large enough to be viable n Genetic Groups of Stocks share: –Major Phylogenetic Associations = ESU? –Adaptation to a common environment = Strata? n Management Groups have similar: –Exploitation rates, hatchery influence, management goals –Can cut across genetic groups

Major Phylogenetic Lineages Species Breeding isolation Recent, incomplete Ancient, complete Selective Forces Weak Strong Disruptive Strong Convergent Populations Diverge into different ecotypes Maintains similar ecotypes Cryptic species

Steelhead Phylogenetic Groups: Defined using patterns of molecular genetic variation Queen Charlotte Glacial Refuge South Coast Refuge South Interior Refuge

Major Phylogenetic Lineages Species Breeding isolation Recent, incomplete Ancient, complete Selective Forces Weak Strong Disruptive Strong Convergent Populations Diverge into different ecotypes Maintains similar ecotypes Cryptic species

Database of Steelhead Stocks Watershed Code DFO Escapement Database Hatchery Records FISS Records Land Form Databases Land Use Databases The Watershed Code links the Stock Database to a variety of useful info

Low Lake InfluenceLand (%Area) Freshwater (%Area) Large WatershedsStream Magnitude (max) Watershed Area Stream Order (max) Cold, High Relief, Temperature (min) High Elevation Elevation (std.dev) Ice (%area) Elevation (max) Elevation (mean) Elev >800m (%Area) Alpine (%area) Temperature (mean) Elev <300m (%Area) Watershed TypeVariable High elevationMinimum Elevation InteriorMigration Distance DryWater Yield Moderate Gradient 16-30% Gradient Gradient 9-15% >70% gradient 51-60% gradient Low Gradient,Gradient Low ReliefGradient 3-8% Elev m Wetlands (%Area) Cold, Temperature (max) High Latitude Latitude Land Form Data can Characterize Watersheds Using Principle Components Analysis

e.g. of a Principle Component Interior, Dry  Coastal, Wet Habitat differences can be used as a proxy for adaptive differentiation

Interior, Dry  Coastal, Wet Low relief, Warm  Cold High Relief

rare common Which stocks have the most unusual habitat? -Interior Watersheds -Low relief coastal -Lake Influence coastal

Genetic Distance from Molecular Markers 2 ESUs 17 Stocks 4 Ecotypes (strata?) Geographic Layout

Large Lake Piscivores Coastal Summer-Run Steelhead Interior Fall-Run Steelhead Phylogenetic Groups Interior South Coast North Coast Ecotypes cut across Phlylogenetic Groups Ecotypes Phylogenetic vs. Adaptive Structure

Contrast with US Pacific NW n Only 3 ESUs –In a Province the size of Wash, Ore, Calif, Idaho combined n Lots of very small coastal stocks –Rocky, heavily-indented coastline Reason: BC was almost entirely glaciated

Steelhead Stock Structure n The smallest independent unit – stock = VSP? –Genetically isolated –Large enough to be viable n Genetic Groups of Stocks share: –Major Phylogenetic Associations = ESU? –Adaptation to a common environment = Strata? n Management Groups have similar: –Exploitation rates, hatchery influence, management goals –Can cut across genetic groups

Ecotypic Grouping in Steelhead - Run Timing June-July Sept-Oct Dec-April Peak Time of River Entry

Hatchery History of Steelhead Stocks Currently Stocked Stocked Prior to 1993 Never Stocked Hatchery History

Which stocks and ecotypes have not had any hatchery influence? June-July Sept-Oct Dec-April Peak Time of River Entry Currently Stocked Prior to 1993 Hatchery History

Land use data can be used to identify habitat concerns } < 300m Elevation } >50% Gradient

Management Units can also be groups of stocks that share common management goals, issues and policies

Steelhead Stock Structure n Define the Distribution n Define Stock Structure (VSP?) –Use associations between geographical isolation and molecular genetic variation n Define Genetic Groups –Major Phylogenetic groups share a common ancestry (ESU?) –Ecotypes share common environments (Strata?) n Define Management groups

Conservation Status Healthy Conservation Concern Extreme Conservation Concern

NeutralConvergentDisruptive Selection gradient Genetic isolation Recent, incomplete Ancient, complete Adaptive differentiation Differentiation at neutral loci Size of Unit

NAMECOQUITLAMPITT STOCK_NO_(WShedCode) ORDER46 MAGNITUDE81525 CONNECTS_T CONNECTS_AT (km)3437 Number of 3rd Order streams414 Watershed Area (km2) MGMTAGGNfraserNfraser STATUSExtremeCCExtremeCC X Albers Y Albers Run TimingWinterWinter Hatchery ClassificationWildWild Last Date StockedJun-96 Max Size (g)192 Max Number Max Size since 1993 (g)192 Max No since Monitored?NoNo Anadromous Length (km) Distance from Ocean (km)3437 ObStructionsYesYes Harvest Analysis ObservationYesYes Steelhead ObservationYesYes Salmon Spp ObservationYesYes Coho ObservationYesYes Rainbow ObservationYesYes Other useful info

Fish Presence/Absence Information is used t Steelhead Sportfish Record Steelhead Inventory Record Salmon Inventory Record Coho Inventory Record Rainbow Trout Record

Allozyme Frequencies in Steelhead vary among adjacent streams

Rainbow Trout Distribution in BC Out of Range Rainbow Trout

Rules for defining stocks n Find all streams that enter the Ocean Directly n Find “Large” river tributaries n Apply size constraints based on measures of watershed size