Examining Freshwater and Marine Habitat Use by Juvenile Blueback Herring (Alosa aestivalis)
Through Otolith Microchemical Methods
Molly Payne WynneDr. Karen Wilson
University of Southern MaineDepartments of Biological Sciences and Environmental Science
Acknowledgements
Maine Sea Grant
Maine EPSCoR Sustainability Solutions Initiative
Alewife Stock Structure in the Gulf of Maine Project (NFWF Grant)
Dr. T. Willis and the Wilson/Willis Lab Members
The Alewife harvesters of Maine and Maine Department of Marine Resources
River Herring Landings (NMFS)
Freshwater
Spring Fall
Ocean adults
eggs young of year
Juveniles
spawning adults
Approach: Otoliths as Natural Tags
Sectioned Otolith at 400x: M. Payne 2012
CalciumStrontiumBariumManganese
Otoliths reflect ambient water chemistry (Campana 2005)
Otoliths as Natural Tags:Require Differences in Water Chemistry
Freshwater:↓ Sr ↑Ba
Seawater:↑Sr ↓Ba
Otoliths as Natural Tags: Field Verification Sr:Ca
0 5 10 15 20 25 30 35 400
1
2
3
R² = 0.68718575068141
Salinity (ppt)
Sr:C
a X1
00
0 5 10 15 20 25 30 35 400
0.02
0.04
0.06
0.08
0.1
R² = 0.606411802104365
Salinity (ppt)
Ba:C
a X1
00Otoliths as Natural Tags: Field Verification Ba:Ca
Research Questions
Habitat Use: ↑Estuary = ↑ Residency
Growth: ↑Estuary =↑Growth
Differences Among Runs: Otolith A ≠ Otolith B
Methods
Study SitesSite Selection
Ken-nebec
St. George
Orland Patten East Machias
0
1000
2000
3000
4000Si
ze o
f Est
uary
(ha)
Rostrum
Postrostrum
Ventral Edge
Dors
al E
dge
1mm
M. Payne 2013
CoreFirst AnnulusFirst Annulus
Otoliths
Otolith Microchemistry Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS)
Otolith at 400x - M. Payne 2013
Core (age=0)
1mm
Otolith Microchemistry: Interpretation
-800 -600 -400 -200 0 200 400 600 8000123456
Distance from Core (microns)
Sr:C
a x1
000
Migration PeakFreshwater/ Low Salinity
Migration Peak
Low Salinity Habitat Use Value (LSHU)
<1 = migrated to sea before the end of the first year of growth>1 = migrated after the first year;
overwintered in estuary
LSHU= 0.48
0 100 200 300 400 500 600 7000
2
4
6
Distance from Core (microns)
Sr:C
a x1
000
# of shiftsMagnitude of Sr:Ca
1
3
2
1.65
3.00
4.15
Regime Shifts (Rodionov 2004)
-800 -600 -400 -200 0 200 400 600 8000
1
2
3
4
5
6
Distance from Core (microns)
Sr:C
a x1
000
Otolith Width at EgressOtolith Width at Year 1
Back Calculation: Length at Year 1 and Egress
Back Calculation: Length at Year 1 and Egress
0 200 400 600 800 1000 12000
20
40
60
80
100
120
f(x) = 3.963731781602E-05 x² + 0.0435877125033645 x + 12.971955869558R² = 0.966493250925319
Otolith Width (microns)
Tota
l Len
gth
(mm
)
LSHU
No. of Regime Shifts (Sr, Ba, Mn)
Growth Proxy
Multiple Discriminant Function Analysis
Results
James McCarthy 2013
-900 -700 -500 -300 -100 100 300 500 700 9000
1
2
3
4
5
6Benton FallsDresden MillsWinneganceSeven Tree PondOrland DamPatten PondHadley Lake
Distance from Core (microns)
Aver
age
Sr:C
a x1
000
Habitat Use: Alternative Life Histories
0 100 200 300 400 500 600 700 8000
1
2
3
4
5
6
7
8
9
Distance from core (microns)
Sr:C
a x
1000
Habitat Use: Alternative Life Histories Winnegance
0 1 2 3 4 5 6 7 80
50
100
150
200
250
300
Total Length
Estimated Length Year 1
Estimated Length at Egress
Leng
th in
mm
Bent
on F
alls
Orla
nd D
am
Patte
n Po
nd
Hadl
ey L
ake
Seve
n Tr
ee
Win
nega
nce
Dres
den
Mill
s
Growth: Lengths at Year 1 and Egress
Classification
%correct
Benton Falls 35
Dresden Mills 60
Hadley Lake 67
Orland Dam 35
Patten Pond 50
Seven Tree Pond 26
Winnegance 85
Total 50
Differences Among Runs:Multiple Discriminant Function Analysis
→Growth Proxy →LSHU Value→# Regime Shifts
[Sr: Ca, Ba:Ca, Mn:Ca]
ConclusionsHabitat Use: ↑Estuary ≠ ↑ ResidencyTwo rivers showed habitat use as predicted although overall a correlation with estuary size and distance to sea was not found
Growth: ↑Estuary ≠↑GrowthFish with the lowest LSHU (Winnegance) were significantly shorter at EgressWetland habitat (Mn:Ca) may infer a growth advantage; longer lengths at Egress
Differences Among Runs: Otolith A ≠ Otolith BWinnegance and Patten Pond show alternative migratory patterns compared to other runsOtolith methods are promising in terms of run differentiation
Implications/ Future Directions Otolith microchemistry can be
used to study habitat use in Maine rivers!
Freshwater and estuary habitats are important for recruitment to adult populations
Variation in Ba:Ca and Mn:Ca signatures in freshwater (otolith and water chemistry) could be used to identify origin at a finer scale
Questions?
Zachary Whalen 2013
Length at Egress and Mn:Ca
0 10 20 30 40 50 60 70 80 90 1000
0.02
0.04
0.06
0.08
0.1
0.12
0.14
Benton FallsDresden MillsWinneganceSeven Tree PondOrland DamPatten PondHadley Lake
Estimated Length at Egress (mm)
Max
imum
Mn:
Ca R
egim
e
r = 0.641
Top Related