Top 4 Threats to Lake Huron

1. Top 4 Threats to Lake Huron

2. Water Contamination

4. Herring Gulls • Indicator of environmental health and contamination • DDT, dieldrin, PCBs, PCDDs • 1970s  1980s  1990s  present

5. Phosphorus Sources - agricultural runoff - residential contamination The Problem - increased nutrient loading The Effects - massive algal blooms (right) - eutrophication/hypoxia - loss of habitat for species - poor conditions for human activities

7. New Threats • PBDE (polybrominateddiphenyl ethers)= flame retardants • PFOS (perfluorooctanesulfonate) = surfactants • Why does it matter • Recent introduction  don’t know the impact • Persistent pollutant  maintained in a system until consumed • Few point sources  atmospheric deposition

8. Areas of Concern • St. Clair River • Industrial, agricultural and residential pollutants • High concentrations of chemical/nutrient pollutants • Loss of habitat, poor water quality, impact on benthic level, species deformities

9. Climate Change & Water Levels

10. With increased temperatures occurring globally, water levels have been increasing around the world, except for the Great Lakes. Why?

11. The Whys • Increased temperature = increased evaporation • Shorter winters with less snowfall with less ice cover (not including this winter OK) • Human consumption and use • Artificial shoreline

12. Impacts  Temperature • Increased aquatic plant growth • Lower dissolved oxygen levels • Some areas made inhospitable • Displacement • Alewife (temperature dependent) • Impact on cellular biology • Increases metabolic rate of fish

13. Impacts  Water Level • Lower Water Levels = Higher Demand • Cut off from the Wetlands • Habitat Loss • Water Purification • Oliphant

14. The Conundrum What we don’t know Vs. What we do know • St. Clair dredging • Creating artificial walls • Increased carbon dioxide levels

15. Habitat Loss

16. Agricultural

17. Industrial

18. Residential/Public

19. Invasive Species

21. Zebra & Quagga Mussel • Habits • Reproduce rapidly • Dense colonies • Filter vacuum Impacts/Issues Zebra - aggressive filter compete with other v benthic organisms - change the nature of lake bottom - bioaccumulation of toxins Quagga - deep/cold water potential

22. Diporeia 2000 2003 2007

23. North Central South 2000 Adult Calanoids Immature Calanoids Adult Cyclopoids Immature Cyclopoids Other Cladocerans Bosmina Daphnia 2001 Biomass (mg/m3) 2002 2003 2004 2005

24. The Round Goby Habits • Aggressive competitor • Food: bivalves, fish eggs • Impacts/Issues • Relationship with zebra mussel • Feed on native fish eggs/fry • Devastation of fisheries • Competition for native species • Mottled Sculpin

25. Sea Lamprey • Habit • Aggressive fish predator (40lbs) • No natural predators • Impact/Issues • Devastating fisheries

26. Spiny Water Flea • Habit • Feed on daphnia zooplankton • Resilient reproductive method • Adapted to cool ecosystems • Impact/Issues • Consume large amounts of zooplankton (daphnia) • Reproduce during all times of the year • Few predators

27. Viral Hemorrhagic Septicemia • Habit • New virus to the Great Lakes • Causes the hemorraging of body and organs • Non-discriminatory at colder temperatures • Impact/Issues • Highly contagious • Devastation of fisheries

28. Asian Carp • Habit • Refers to four species (bighead, grass, silver, black) • Huge consumers of aquatic plant life • Temperature tolerance • Various diets • Impact/Issues • Varied diets = devastation • Decline in commercial fisheries