understanding and predicting fish mercury in the …sdw.enr.gov.nt.ca/nwtdp_upload/2 swanson...
TRANSCRIPT
![Page 1: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/1.jpg)
UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO
Heidi Swanson, George Low, Mike Low, Brian Branfireun With: Dean Holman, Melaine Simba, Darcy Simba, Gabe Chicot Ernest Hardisty, Angus Sanguez, Laura Sanguez, Rufus Sanguez,
Victor Jumbo, Alfred, Victoria Gargan
![Page 2: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/2.jpg)
MAHSI CHO!
![Page 3: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/3.jpg)
OUTLINE
• Why are we doing this project • How does mercury get to the North? • Why is Hg high in some fish but not in
others? • Project methods • Interim Results • TK, Management • Take-Home Messages
![Page 4: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/4.jpg)
QUESTIONS FROM COMMUNITIES
• Why do some lakes have high mercury and other lakes have low mercury?
• Why are levels increasing in some lakes but decreasing in other lakes?
• How will climate change and development affect fish mercury levels?
![Page 5: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/5.jpg)
QUESTIONS AND CONCERNS
• We want to feel safe eating the fish, and we want the same for our grandchildren
• If mercury levels are high, is there something we can do about it?
![Page 6: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/6.jpg)
MERCURY IN THE ENVIRONMENT
• Mercury is natural
• We don’t make more mercury, but we move it around
• First, only nature moved it around
• Since about 1850, we have released mercury trapped in coal into the air
![Page 7: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/7.jpg)
Mer
cury
leve
ls
Trophic level
PREDICTING FISH MERCURY LEVELS
Most mercury
Least mercury
![Page 8: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/8.jpg)
Highest mercury
Biggest fish
Oldest fish
Lowest mercury Youngest fish
Smallest fish
![Page 9: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/9.jpg)
How much mercury in this fish?
Age Growth rate
What do I eat? (trophic level)
Where do I eat it?
What other fish are in my
lake? (food chain length)
Lake temperature?
Lake acidity?
How much oxygen?
Water clarity
Lake nutrient levels Size
Lake tea-colored or
clear?
![Page 10: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/10.jpg)
WHAT HAVE WE BEEN DOING?
• Lakes: Sanguez, Ekali, Tathlina, Kakisa, Mustard, McGill, Gargan, Trout
• Community monitors and fishers chose fishing spots and collected fish
• Also collected bugs, water, sediment
![Page 11: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/11.jpg)
• Take flesh sample, sort invertebrates
• Measure fish mercury level, fish size, age, trophic level, chemistry and mercury in water
WHAT HAVE WE BEEN DOING?
![Page 12: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/12.jpg)
LAKE WHITEFISH
Standard size: 400 mm
![Page 13: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/13.jpg)
NORTHERN PIKE
Standard size: 650 mm
![Page 14: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/14.jpg)
WALLEYE
Standard size: 450 mm
![Page 15: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/15.jpg)
• All Lake Whitefish below 0.5 ppm commercial sale guideline • Most also below 0.2 ppm
subsistence guideline • Northern Pike higher:
Sanguez, McGill, Ekali but most below 0.5 ppm, (except Sanguez)
• Walleye highest: higher in Sanguez, McGill, Tathlina, lower in Ekali and Trout
MERCURY TO DATE?
![Page 16: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/16.jpg)
• Fish Hg related to • Size, age, trophic position • This explains differences
among *species* • Differences among lakes
• Not explained by these factors
• Not explained by Hg in water or lake tea colour
EXPLAINING FISH HG (INTERIM)
![Page 17: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/17.jpg)
How much mercury in this fish?
Age Growth rate
What do I eat? (trophic level)
Where do I eat it?
What other fish are in my
lake? (food chain length)
Lake temperature?
Lake acidity?
How much oxygen?
Water clarity
Lake nutrient levels Size
Lake tea-colored or
clear?
![Page 18: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/18.jpg)
EXPLAINING AND PREDICTING FISH HG: WALLEYE (INTERIM)
![Page 19: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/19.jpg)
EXPLAINING AND PREDICTING FISH HG: WALLEYE (INTERIM)
![Page 20: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/20.jpg)
EXPLAINING AND PREDICTING FISH HG: PIKE (INTERIM)
![Page 21: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/21.jpg)
• McGill and Sanguez lakes not fished as much as they used to • Fish likely growing more
slowly (still finishing age and growth analysis)
• Fish-down to reduce Hg levels – pilot project in Sanguez Lake
• Beaver dam removals?
TK AND MANAGEMENT
![Page 22: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/22.jpg)
YOUTH ENGAGEMENT
![Page 23: UNDERSTANDING AND PREDICTING FISH MERCURY IN THE …sdw.enr.gov.nt.ca/nwtdp_upload/2 Swanson Fish... · UNDERSTANDING AND PREDICTING FISH MERCURY IN THE DEHCHO Heidi Swanson, George](https://reader033.vdocuments.mx/reader033/viewer/2022050401/5f7f725651c85f6bdf61a89d/html5/thumbnails/23.jpg)
TAKE HOME MESSAGES
• Hg low in Whitefish, higher in Pike, highest in Walleye • Pike: highest in Sanguez Lake • Walleye: highest in Sanguez, McGill, Tathlina Lakes
• Lake differences • Partly explained by lake chemistry (sulfate and chl-a) for
walleye • Partly explained by where they are feeding for Northern
Pike • Monitor water chemistry! (Climate change) • More results to come • Management: explore potential for fish-downs
• More investigation: beaver dam removal