contaminant exposure in marine foraging river otters cait nelson m. sc. candidate faculty of land...

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)

0

2

4

6

8

10

12

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

0

10

20

30

40

50

60

70

80

90

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

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

(%)

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

2

3

4

5

6

7

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

2

4

6

8

10

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?