contaminant exposure in marine foraging river otters cait nelson m. sc. candidate faculty of land...
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Contaminant Exposure in Marine Foraging River Otters
Cait Nelson M. Sc. Candidate
Faculty of Land and Food Systems
September 24th 2010
Coastal River Otters
Lontra canadensis
Background
To investigate the effects of persistent organic pollutants on top predator wildlife species
Why is this important?Bioaccumulation and Physiological EffectsPopulation Declines...
Why study river otters?
• Relatively small home ranges
• Finer scale contamination
• Do not hibernate or migrate
• Exposed to pollutants year round
• Mustelids are sensitive to pollution
• Top Predator of Marine Based Food Web
• Maintain System Stability
• Sentinel Species for Ecosystem Health
Why study river otters?
How To Study River Otters?
Non-Invasive Scat Sampling
Communal Latrine Site
Previous Research
Elliott et al. 2008
• Fresh faeces at latrine
• Pooled sample for analysis
• Latrine = sampling unit
Previous Research
Vic Esq Nan Pow R. Cow Clay
(1998)
Vic Van Cmx
(2004)
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14
108.4 67.6
Critical Level (9 mg/kg lw)
ΣPCB
con
cent
ratio
n (m
g/kg
lw)
No Effect Level (4 mg/kg lw)
PCBs in feces (geomean & range)
(4) (4) (5) (5) (2) (5) (7) (7) (7) (18) (9) (35)
(2006)
Esq
22.2
Non-hb
14.9
Vic
38.2
Assessment of Contaminant Exposure, Diet and Population Metrics of River Otters Along the Coast of Southern
Vancouver Island
Daniel A. Guertin
Master’s Thesis Spring 2009
Department of Biological Sciences
Simon Fraser UniversityJared Hobbs
Objectives
Individual-based Approach
1. Fecal DNA Genotyping
2. Diet composition
3. Track Contaminant levels
4. Spatial relationships
Guertin Thesis 2009
Jared Hobbs
Study Area
Guertin Thesis 2009
Methods
Winter/Summer 2006Mapped Active Latrines (80kms)
Split scat samples1. DNA and diet analysis2. Contaminant analysis
Guertin Thesis 2009
Methods
Guertin Thesis 2009
DNA Analysis
1. Screened samples Diet Analysis
2. Fecal DNA Genotyping - Molecular fingerprints (8 microsatellite loci)
University of Wyoming, Dr. Merav Ben-David
Methods
Contaminant Analysis
15 OC-pesticides (by class)- DDT and metabolites (ΣDDT)- Chlorobenzenes (ΣClBz)- Chlordane compounds (ΣCHLR)- Hexachlorocyclohexanes (ΣHCH)- Total pesticides (ΣPest)
39 PCB Congeners- Total PCBs (ΣPCBs)
DDT ClBz
Chlordane HCH
PCB
Results
DNA Analysis- Low genotyping success (12%)...
- Successfully genotyped 49 individual otters
- 28 individuals with >2 samples (65 samples)
- Only these samples were analyzed for diet and contaminants
Jared Hobbs
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100G
unne
ls
Scul
pins
Pric
kleb
acks
Toad
fish
Clin
gfish
Flatf
ish
Snai
lfish
Gre
enlin
gs
Crus
tace
ans
Prey item
Freq
uenc
y of
occ
urre
nce
in fa
eces
(%) Harbours
Non-Harbours
Fecal Diet Analysis
Guertin Thesis 2009
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*
Gun
nels
Scul
pins
Pric
kleb
acks
Toad
fish
Clin
gfish
Flatf
ish
Snai
lfish
Gre
enlin
gs
Crus
tace
ans
Prey item
Freq
uenc
y of
occ
urre
nce
in fa
eces
(%)
Toadfish
Harbours
Non-Harbours
Harbours
Guertin Thesis 2009
Fecal Diet Analysis
0
10
20
30
40
50
60
70
80
90
100
*
Gun
nels
Scul
pins
Pric
kleb
acks
Toad
fish
Clin
gfish
Flatf
ish
Snai
lfish
Gre
enlin
gs
Crus
tace
ans
Prey item
Freq
uenc
y of
occ
urre
nce
in fa
eces
(%)
Crustaceans
Harbours
Non-Harbours
Harbours
Guertin Thesis 2009
Fecal Diet Analysis
0
1
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ΣDDT ΣClBz ΣCHLR ΣHCH Mirex ΣPest ΣPCBs
Conc
entr
ation
(mg/
kg lw
)
wintersummer
No season effect
Contaminants in Feces (by season)
OC-pesticides
CompoundGuertin Thesis 2009
0
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4
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12
* * *
VictoriaEsquimaltNon-harbours
Location effect
ΣDDT ΣClBz ΣCHLR ΣHCH Mirex ΣPest
Contaminants in Feces (by location)Co
ncen
trati
on (m
g/kg
lw)
a b b a b ba b b
*
ΣPCBs
a
b
c
OC-pesticides
CompoundGuertin Thesis 2009
Vic
Hb
Victoria, BC
0.2
7.1
6 weeks
ΣPCBs in otter faeces
Critical level: > 9 mg/kg lwNo effect level: < 4 mg/kg lw
13.4
6 weeks
6.8
ΣPCBs in otter faeces
Critical level: > 9 mg/kg lwNo effect level: < 4 mg/kg lw
Victoria, BC
Summary
• Highest fecal [PCB] in Victoria Harbour
• The effects of PCB exposure extend beyond Victoria Harbour
• Scat Sampling + Fecal DNA Genotyping to investigate contaminant exposure, diet in individual otters
• Low success in Fecal Genotyping (12%)
Jared Hobbs
0.2
7.1
6 weeks
Conclusion
• Variability in fecal PCB levels, Not likely to reflect body burden
• Limited Understanding Population and Ecosystem Health
Jared Hobbs
My Research
Objectives
1. Home range and movement patterns
2. [PCB] in fat, blood, feces and prey
3. Non-invasive techniques
Expand sampling season...
Jared Hobbs
My Research
Methods
Home Range and Movement
• 13 Adult Otters (5F, 8M)
• Tagged with VHF transmitters
• Track for 12 months
My Research
Methods
[PCB] in fat, blood, feces and prey
• High resolution chemical analysis
• Test bioaccumulation model
My Research
MethodsNon-invasive techniques• Scat Sampling (split three ways)
1. DNA
2. Contaminants
3. Stress Hormones
• Improve Genotyping Success
My Research
MethodsGenetic Data• movement (compare to telemetry data)
• social structure/relatedness
• population estimate (mark/recapture)
Practical applications in management and monitoring contaminated sites
Jared Hobbs
Thank You!Co-Supervisors:
Dr. John Elliott, Environment Canada
Dr. Kim Cheng, UBC Avian Research Centre
Genetic Data Center:Dr. Carol Ritland
BC Ministry of Environment:Dr. Helen Schwantje
Field Crew and Volunteers:Shawn Dalman
Caeley Thacker and Ruby KaneDaniel Guertin Jared Hobbs
Questions?