Allan B. CostelloAllan B. Costello11, Ted Down, Ted Down22, Rick Taylor, Rick Taylor11

1 1 –– Native Fish Research Group, University of British ColumbiaNative Fish Research Group, University of British Columbia2 2 -- British Columbia Ministry of Environment, Aquatic Ecosystem SciBritish Columbia Ministry of Environment, Aquatic Ecosystem Science ence

Drawing the circles:Drawing the circles:Defining distinct population segments in Defining distinct population segments in

British ColumbiaBritish Columbia

‘‘Typical’Typical’CCTCCT

populationpopulation

Population sizeand variability

Number and compositionof spawners

Interactions withother populations

Relation to range-widebiodiversity

Defining a ‘typical’ populationDefining a ‘typical’ population

Nested ApproachNested Approach

BCBC

PacificPacificOcean

OceanWAWA

OROR

CACA

AKAK

1. Mating System1. Mating System–– intensive study of intensive study of

single systemsingle system

2. Population Structure2. Population Structure–– 48 adjacent streams in 48 adjacent streams in

Georgia Basin, QCIGeorgia Basin, QCI

3. Range3. Range--wide Structurewide Structure–– Major lineages from AK Major lineages from AK

to CAto CA

1. Chonat Lake Mating Study1. Chonat Lake Mating Study

• What is the size of a typical spawning population and does it vary between years?

–– Chonat Lake, Quadra Chonat Lake, Quadra IslandIsland

–– Fish fence monitored Fish fence monitored during 2001, 2002 during 2001, 2002 spawning seasonsspawning seasons

–– 7 7 microsats microsats used to used to perform parentage perform parentage analysis of YOY fryanalysis of YOY fryCampbell River

Chonat Lake Chonat Lake (48 ha)(48 ha)

OutletOutlet

Inlet (710 m Spawning stream)Inlet (710 m Spawning stream)

Chonat spawnersChonat spawners

2001200124 Males24 Males57 Females57 Females81 Total81 Total

2002200223 Males23 Males21 Females21 Females44 Total44 Total

Length Frequency Distribution (2002 spawners)

0

5

10

15

20

25

30

35

<15 15-20 20-25 25-30 30-35 35-40 40-45 <45

Fork length (cm)

Num

ber

Males

Females

SR-Males

Length Frequency Distribution (2001 spawners)

0

5

10

15

20

25

30

35

< 15.0 15.1 - 20.0 20.1 - 25.0 25.1 - 30.0 30.1 - 35.0 35.1 - 40.0 40.1 - 45.0 > 45.0

Length (cm)

Num

ber

MalesFemalesSR-M

Seals?Seals?

11.792.29 6.973.32Variance (s2)

3664Nb

20(95%)

21

31(54%)

57

FemalesFemales

8%11%Nb/ N

22(96%)

16 (67%)

Successful spawners

2324Total spawners

MalesMales

20022001Parentage Parentage resultsresults

2. Georgia Basin Population Structure

• 48 streams from Vancouver Island, Lower Mainland, and Gulf Islands

• QCI samples for comparison

• 6 microsats used to infer geneflow

Campbell River

Tofino

Vancouver

Victoria

C am p b el l R iver

To fin o

Van co u ver

Victo r ia

Clayoquot Sd

Juan de Fuca

Vancouver Is - EastSunshine Coast

Chonat Lake

Georgia Basin MP sampling

Population structure results

• Pops structured at stream level

• Metapopulation structure apparent at larger scales

• Not strictly based on proximity

East Vancouver Island,

Gulf Islands, Outer Sunshine Coast

Rainbow trout outgroups &

above barrier pops

Strait of

Juan de Fuca

Clayoquot Sound, QCI, AK

Sechelt

Inlet

Factors structuring diversity

• Deep water channels?– GIS least-cost path

modelling

• Shoreline attributes?– Analysis of shoreline

unit data (CCA)

• Generate predictive rules?

3. Range3. Range--wide biodiversitywide biodiversity

• How is CCT biodiversity distributed over its entire range?– Distribution of major

conservation units – DNA sequencing of

nuclear (GH2), and mtDNA genes (ND1 and D-loop)

– samples from CA to AK

SE ALASKA

AT64%

TG18%

AG18%

NORTH COAST

TG35% AG

41%

AT24%

QCI

A T

63%

A G

19%

T G

18%

CENTRAL COAST

TG

48%

AG50%

AT2%

LOWER MAINLAND

AG86%

AT

7%

TG7%

GEORGIA BASIN

A G

95%

A T

5%

WEST-VAN ISTG4%

AT

12%

AG84%

COASTAL WA

AT26%

AG74%

Distribution of Distribution of GH2 GH2

haplotypeshaplotypes“AT” TYPE

“AG” TYPE

“TG” TYPECentral coast

lineage?

?

Southernlineage

Northernlineage

Phylogeography summaryPhylogeography summary

•• Complex phylogeography in BCComplex phylogeography in BC–– Multiple refugia likelyMultiple refugia likely–– Mix of refugial races in most areasMix of refugial races in most areas

•• Requiring samples from periphery of range: Requiring samples from periphery of range: CA, OR, WA, AKCA, OR, WA, AK

Georgia Depression DU

Coast and Mountains(Outer Coast) DU

Chonat Lake

??

So, what is a CCT population?

• Variable, supported by few spawners• Reproductively isolated over small scales• Structured into loose regional groups• A product of numerous historical and

contemporary factors• It’s complicated!

Acknowledgments

• BC Habitat Conservation Trust Fund (HCTF)• BC Ministry of Environment, regional biologists• Grant B. Culley, Jr. Foundation• Pacific States Marine Fish Commission and US Fish and Wildlife Service (Travel Assistance)

Ptolemy-Ramsay photo

I like cutthroat!