arctic cisco genetics and otolith microchemistry
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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
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