Coasters in Coasters in the newsthe news

Distribution of coaster brook troutDistribution of coaster brook trout

Distribution of coaster brook troutDistribution of coaster brook trout

Lake Superior

Canada

United States

What Are Coaster Brook Trout?What Are Coaster Brook Trout?

Life history variant?Life history variant?

• part of natal river part of natal river populationpopulation

• straying between riversstraying between rivers

• long range movement long range movement between populationsbetween populations

Unique stock?Unique stock?

• Evolutionary Significant Evolutionary Significant UnitUnit

MethodsMethods

Resolving the genetic identify Resolving the genetic identify of coastersof coasters

• microsatellite DNAmicrosatellite DNA

• high resolution high resolution

• identify individuals identify individuals and populationsand populations

Single populations?Single populations?

JP

CY

LC

SWDB

PL

H

C

0.01

Genetic distances Genetic distances among sampled among sampled

populationspopulations

Cypress R.Cypress R.

Jackpine R.Jackpine R.

Pearl R.Pearl R.

Little Cypress R.Little Cypress R.

Dublin Cr.Dublin Cr.

Relatedness of Individual River Relatedness of Individual River Resident Brook TroutResident Brook Trout

coastercoaster

hatcheryhatchery

Relatedness of Individual Brook Relatedness of Individual Brook TroutTrout

0

5

10

15

20

25

5 6 7 8 9 10 11 12 13 14

(-) log likelihood of individual genotypes

Nu

mb

er

of

Ind

ivid

ua

ls

river brook trout

coasters

ResultsResults

• coaster brook trout coaster brook trout genetically distinct straingenetically distinct strain

• coasters produced by river coasters produced by river populations (life history populations (life history variant) variant)

• vectors of gene flow vectors of gene flow between riversbetween rivers

Unanswered QuestionsUnanswered Questions

• how do we bring them back?how do we bring them back?

•what makes a coaster? what makes a coaster? (habitat / life history)(habitat / life history)

• optimal vs. potential habitat optimal vs. potential habitat

• competition with exotics?competition with exotics?

• genetic structure of coasters genetic structure of coasters throughout Lake Superiorthroughout Lake Superior

ImplicationsImplications

• coasters come from river coasters come from river populationspopulations

• interdependence of lake interdependence of lake and river populationsand river populations

• making a “coaster brood making a “coaster brood stock” won’t guarantee stock” won’t guarantee successsuccess

• management of source management of source rivers is necessary for rivers is necessary for recoveryrecovery