Evaluating genetic structure of interior Redband trout in Idaho

Christine Kozfkay, Matthew Campbell, Kevin Meyer, Dan Schill, Bruce Zoellick.

Interior O. Mykiss in Idaho Found east of the

Cascades upstream to Shoshone Falls on Snake R. and Kootenai Falls on Kootenai R.

Not in Clark Fork or Coeur d'Alene drainages

Resident pops above Hells Canyon Dam are found in Boise, Weiser, Payette, Owyhee, Wood, Snake, Bruneau R. drainages

• Includes formerly

anadromous steelhead

Interior Columbia R. O. Mykiss

Boise

Found in montane streams as well as arid desert drainages

© Juan Calvillo.

Interior Columbia R. O. Mykiss

Montane Streams: Higher elevations, cooler summer water

temperatures, larger substrate, more canopy covering, higher gradient streams

Desert Streams: Elevations – 750 to 2560 m, summer water

temperatures 18 – 26 degrees

Desert vs. Montane Populations

Desert Streams: Elevations – 750 to 2560 m, summer water

temperatures 18 – 26 degrees

Desert vs. Montane Populations

Anadromous Columbia R. O. mykiss (Steelhead)

Genetic Structure has

been intensively studied

Anadromous O.

mykiss are structured at the watershed level

Goal: Investigate genetic structure of resident O. mykiss in Idaho

Role of environment, hatchery stocking,

anadromous life-history

Hypothesis 1:

• Ho: Genetic structure (FST) is the same for populations in montane and desert drainages

Follows stream hierarchy and/or geographic

distance (like steelhead)

Montane:

Desert:

Ha: Genetic structure (FST) is greater for populations within the desert drainages due to habitat

Hypothesis 2:

• Ho: Genetic diversity levels are the same for populations in montane and desert drainages

Montane:

Desert:

Ha: Genetic diversity is greater for populations within the montane drainages because gene flow is higher

Montane:

Desert:

Ha :Genetic diversity levels are similar among montane and desert populations but diversity is different (selection).

Sampling

2,271 samples collected from 8 watersheds in Idaho

4 desert, 4 montane Snake

Owyhee

Bruneau

Payette

Big Wood

Boise

Salmon Falls

Weiser

13 microsatellite loci

Methods

• Genetic diversity = avg. number of alleles per

locus, avg. heterozygosity • Compared across groups (montane vs. desert, 8

watersheds) and to steelhead

Methods Cont’d • Genetic Structure: Dendrogram - NJ tree using CSE gen. distance FST analyses AMOVA analyses - Tests how genetic

variation is partitioned between and within groups (Montane vs. Desert, 8 Watersheds, Hybridized vs. Nonhybridized)

Results

0.1

Bruneau R Juniper Cr

Squaw Cr Shack Cr.

Cottonwood Cr. NF Salmon Falls Cr.

MF Shoshone Cr. Crab Cr.

McMullen Cr. *Deer Cr.

Willow Cr. Owyhee Cr.

NF Owyhee Cr. Keithly Cr.

Indian Cr. Cold Springs Cr.

Little Canyon Cr. Bennett Cr. Dive Cr.

Jordan Cr. Tripod Cr.

Willow Cr. EF Big Wood Cr.

Red Warrior Cr. Big Wood R.

NF Thompson Cr. Little Wood R.

Copper Cr. Smith Cr.

SF Boise R. Salmon Falls Cr. Boise R.

McConaughey Arlee

Hayspur Erwin

Hilderbrand D Kamloops

Hilderbrand Eagle Lake Shasta

Fish Lake MW

Jarbidge R. Petes Cr.

2nd Fork Squaw Cr. Beaver Cr.

Shoofly Cr. Little Jacks Cr.

Wickahoney Cr. Duncan Cr.

Big Jacks Cr. Fawn Cr.

Silver Cr. Jump Cr. (above)

Jump Cr. (below)

Little Weiser Cr. Hornet Cr.

Big Smokey Cr. Whiskey Jack Cr.

Johnson Cr. Pikes Fork Cr.

MF Boise R. Roaring R.

Longs Cr. Clear Cr. Eightmile Cr.

Williams Cr. Manns Cr.

EF Weiser R. Cedar Cr.

Sinker Cr

Hybridized Pops +

Hatchery References

Genetic Diversity Results • Avg. He ranged from 0.48 to 0.78, Avg. # alleles per locus

ranged from 3.23 to 10.77 • Diversity was significant different in each watershed:

» Weiser River - highest » Snake River - lowest

Genetic Diversity Results • Mountain Pops (no hybrids): He = 0.68, Avg. # Alleles = 4.8 • Desert Pops (no hybrids): He = 0.66, Avg. # Alleles = 4.4 • Hybridized Pops: He = 0.70, Avg. # Alleles = 5.05 • Non-hybridized Pops: He = 0.67, Avg. # Alleles = 4.6

Genetic Diversity Results • Steelhead Pops: He = 0.75, Avg # Alleles = 9.4 Montane Pops (no hybrids): He = 0.68, Avg. # Alleles = 4.4 Desert Pops (no hybrids): He = 0.66, Avg. # Alleles = 4.8

Diversity is higher in Steelhead populations than resident redband trout

populations!

How is diversity partitioned? • Largest amount of diversity partitioned between pops (89%),

between drainages (10%), between montane and desert groupings (1%)

• Diversity between hybridized and non-hybridized groups is

5% while montane/desert groupings is only 1%

How is diversity partitioned? Locus Ots4:

All Loci: N = 186 N = 166 N= 184 N = 189 N = 202

Small

Moderate

Large

Very Large

Geographic Distance

Pair-

wis

e Fs

t Val

ues

Avg. FST Montane = 0.07; Avg. FST Desert = 0.13

FST Results

Genetic diversity is structured at the population and watershed levels

Major Findings

Mountain:

Desert:

Genetic structure (FST) is greater for populations within the desert drainages due to habitat barriers but avg. diversity is not sig. lower

Major Findings

Mountain:

Desert:

Genetic diversity levels are similar among mountain and desert populations and different subsets of the anadromous gene pool are represented in each population

Major Findings

Resident life-history, hybridization, and environmental barriers all influence genetic structure

Montane and desert populations - lower amounts of diversity than steelhead populations but not different

types of diversity.

Management of populations should be at the population and watershed scales

Major Conclusions

Questions?