Arctic Cisco Genetics and

Otolith Microchemistry

Jennifer L. Nielsen

Christian E. Zimmerman

Vanessa Von Biela

USGS Alaska Science Center

Alaska Marine Science Symposium

Anchorage, Alaska

January 22, 2009

Generalized Arctic Cisco Life History

• Recent declines in abundance and size of Arctic cisco – population-of-origin effects?

• Impacts of climate on sustainable harvest – effects of changes in Arctic oscillation and/or changes in prey abundance?

Nuiqsut Subsistence Fishery

Under-ice gillnet subsistence harvest

Migration and Growth in Arctic Cisco

Testing the “Mackenzie Hypothesis”

Colville River, AK

subsistence harvest

2005-2007

Mackenzie River, CA

5 anadromous spawning locations

2007-2008

Beaufort Sea

Gulf of Alaska

Otoliths depict migration history and act as natural growth records

Sr/Ca Ratios

Otolith radius and fish length were proportional

1986

0 200 400 600 800 1000 1200 1400 1600

0.000

0.001

0.002

0.003

0.004

0.005

0.006

1995

0 200 400 600 800 1000 1200

Sr/

Ca

0.000

0.001

0.002

0.003

0.004

0.005

0.006

C

Distance from centrum (microns)

0 200 400 600 800 1000 1200 1400

0.000

0.001

0.002

0.003

0.004

0.005

0.006

D2005:2 vs S2005:2 2005

Distance from centrum (microns)

0 200 400 600 800 1000 1200 1400

0.000

0.001

0.002

0.003

0.004

0.005

0.006

Using Otolith Micro-chemical

Analyses to Understand Fish Populations

Fork length (mm)

100 200 300 400

Oto

lith

rad

ius

(µm

)

0

500

1000

1500

2000

2500Age 1Age 2Age 3Age 4Age 5Age 6Age 7Age 8Age 9Age 10+

Otolith growth vs. fish length1986-2007 (no samples 1989, 2002-2004)

(r2 = 0.84; P < 0.0001)

Young-of-the-Year Otolith Growth

ANOVA: n = 819; p < 0.0001

Growth Year

1975 1980 1985 1990 1995 2000 2005

Re

sidu

al Y

OY

incr

eme

nt s

ize

-200

-100

0

100

2001989 Pacific Ocean climate shift

(Hare & Mantua 2000)

1997 Pacific Ocean climate shift

Winter Arctic Oscillation Index

p=0.0262

Growth Year

1980 1985 1990 1995 2000

Res

idu

al Y

OY

in

crem

ent

size

-100

0

100

Win

ter

AO

-1

0

1

2

YOY increment sizeWinter AO

r 2 = 0.19

Growth Year

1980 1985 1990 1995 2000

Res

idu

al Y

OY

in

crem

ent

size

-100

0

100

Mea

n T

emp

erat

ure

(ºC

)

10

12

14

16

18YOY increment sizeMean air temperature, Inuvik, June-July

r 2 = 0.15

Air Temperature(Inuvik May-August)

Young-of-Year Growth Correlations

Environmental Factors

Growth Year

1980 1985 1990 1995 2000

Res

idu

al Y

OY

in

crem

ent

size

-100

0

100

Win

d s

pee

d (

m/s

)

4

5

6

7

8

9

YOY increment sizeEast wind speed, Barrow, July-August

r 2 = 0.16

Easterly Wind Speed(Barrow July- August)

r2 = 0.16r2 = 0.15

No correlation found between YOY growth

and proportion of easterly winds

Mackenzie River Dischargem3/s, April-June

P = 0.0001

Growth Year

1980 1985 1990 1995 2000

Re

sid

ua

l Y

OY

in

cre

me

nt

siz

e

-100

0

100

Riv

er

dis

ch

arg

e (

m3

/s)

8000

10000

12000

14000YOY increment sizeRiver discharge, Ft. Simpson,lagged 2 years

r 2 = 0.50

Young-of-the-Year Growth Most environmental factors accounted for only

small proportion of variation in YOY growth 2-yr lagged river discharge accounted for half the

variability in YOY growth YOY growth may increase after high discharge

years when increased nutrient input stimulates lower trophic production

Increased spring river discharge, DOC, and nutrients

(Carmack et al. 2004, Dunton et al. 2006, Holmes et al. 2008)

Increased 1° production in the Mackenzie plume

(Carmack et al. 2004, Garneau et al. 2006, Pedersen et al. 2008)

Also consider transport of planktonAcross shelf and between

N. Pacific and W. Arctic OceansCarin Ashjian et al. 2005 & 2008

Higher zooplankton abundance in the next generation (2nd year)(Schell et al. 1998, Dunton et al. 2004)

2-year Lag

Growth Hypothesis

Genetic Data

Population-of-Origin Analyses

• 11 microsatellite loci genotyped for Arctic cisco (28 loci screened and 4 new loci maximized)

• mtDNA ATPase6 gene sequenced (594 nt)

Microsatellite alleles mtDNA nucleotide sequence

N = 86 (2005)

N = 176 (2006)

N = 54 (Peel)

N = 60 (Arctic Red)

Genetic Analyses 2005-2007

• Average: NA = 25.5; AR = 15.1; HO = 0.775; HE = 0.774

• All microsatellite loci were in HWE & linkage equilibrium

• Global FIS = 0.000 (p = 0.49) for all loci combined

• No significant pairwise FST differences between collections by year or location (p ≥ 0.21 in all cases)

• No significant differences between Alaskan and Canadian Arctic cisco (pairwise FST = 0.0007, p = 0.11)

• No significant allelic frequency differences among age classes in the 2006 Colville River subsistence fishery (p ≥ 0.09 in all cases)

• STRUCTURE inferred one genetic cluster (K = 1)

11 Microsatellite Loci

• Characterized 19 unique Arctic cisco ATPase6 haplotypes

• No significant pairwise FST differences among haplotype frequencies by year or location

• 4 highly divergent haplotypes present in the Colville River

3 haplotypes aligned with Bering cisco mtDNA

1 unknown haplotype (putative Coregonus spp.)

mtDNA Results

mtDNA Minimum Spanning Network

Sample sizes

• 372 Arctic cisco

• 8 Bering cisco

• 1 unknown Coregonus

Conclusions: YOY Growth

Variation in YOY Arctic cisco growth could be described by: Mackenzie River discharge, air temperature, and easterly wind speed

Best-fit model included variables:

1) Mackenzie discharge lagged 2 years

2) Inuvik summer air temperature

Model explains ~60% of variability in YOY growth 1986-2007

Conclusions: Genetics

• Arctic cisco sampled in the Mackenzie River show high levels of gene flow among putative spawning populations in

the Arctic Red and Peel rivers (panmixia?)

• Arctic cisco from the Colville and Mackenzie rivers lack independent genetic structure.

• Results from this study support the “Mackenzie Hypothesis” with one population of origin for fish caught in the

Colville River subsistence fishery.

• Rare coregonid haplotypes found in Colville River fishery require additional study to determine origins and possible hybridization among North Slope whitefish.

Kate Wedemeyer (Minerals Management Service); Paulo Flieg and Larry Greenland (Aurora Research Institute); Shawn Norbert (Tsiigehtchic resident); Gwich’in Renewable Resource Board (Inuvik); Tetlit Renewable Resource Council (Fort McPherson); Gwichya Renewable Resource Council (Tsiigehtchic) ; Sean Burril; Andy Ramey; Sara Graziano; Larry Moulton; John Seigle, ABR; ConocoPhillips (Anchorage) ; LGL Limited (Anchorage); US Fish & Wildlife Service (Anchorage).

Acknowledgements