Big Traverse Bay Stamp Sands - Great Lakes Fishery Commission
Transcription
Big Traverse Bay Stamp Sands - Great Lakes Fishery Commission
Big Traverse Bay Stamp Sands -Ben Michaels Stamp sands – what are they? • By-product of a crushing process used for turning big rocks into smaller rocks in order to extract metal such as copper. • The small, pulverized rocks (aka stamp sand), contain residual metals, which can be harmful for terrestrial and aquatic organisms living in close proximity to the toxic sand. Stamp sand http://www.geo.mtu.edu/MiTEP/EarthCache/GayStampSands_CW Native sand History • 140 mines and 40 mills across the Keweenaw Peninsula during 1850-1929. Kerfoot et al. 2012 History • 4.8 Mt of copper smelted by 1968 • 360 Mt of stamp sands dumped into various waterbodies, including 64 Mt into Lake Superior. History – Gay, MI • Wolverine and Mohawk stamp mills opened during the early 1900’s and both closed by 1932. – 22.7 Mt deposited into Lake Superior, near Gay, MI. Kerfoot et al. 2012 History • Stamp sands have been migrating southwest along a five-mile stretch of coastline in Big Traverse Bay. Kerfoot et al. 2014 Concern • Threats to ecologically and economicallyimportant lake trout and white fish populations. – Habitat loss – Contamination – High concentrations of Mercury and Copper – Effects on lower trophic organisms – Aesthetic value Concern • Potential economic impacts – Eventual loss of Buffalo Reef to stamp sand encroachment. • Tribal commercial fishery • Recreational fishery – Mitigating losses via lake trout stocking – Cascading effect on local businesses GLIFWC fish population assessments Traverse Bay • Gill-netting – Conducted annually since 1987 during the autumn months at various reefs around the Keweenaw Peninsula. – Determine location, relative abundance, and movement of spawning lake trout and white fish populations via mark-recap. • 6 ft x 750 ft gangs, 4.5 to 5.5 inch mesh. • Buffalo Reef – expanded fishery assessment – Added more sites to area within the reef (2005) in order to determine whether Buffalo Reef was an important spawning area. – Oct. 17 to Nov. 16 – a total of 6,500 ft set GLIFWC expanded assessment and sediment mapping • Environment Canada – National Water Research Institute (NWRI) • (contracted by GLIFWC) • Map the extent of the stamp sands in relation to the reef in order to provide a baseline of the spatial relationship between stamp sands and spawning areas on the reef. • Provide a preliminary assessment of the vulnerability of the reef to contamination by stamp sands. GLIFWC expanded assessment and sediment mapping • Sonar mapping • RoxAnn sediment classification system – The system processes information collected by sounding equipment generated through an in-hull transducer. – Underwater video samples at 41 sites. – Sediment samples at 21 sites. GLIFWC expanded assessment and sediment mapping • Stamp sand and native sand were not acoustically distinct, however, area immediately north of Buffalo Reef likely stamp sand. Great Lakes Research Center • Conducted Light Detection and Ranging (LiDAR) and Multispectral Scanner (MSS) work to map movement and distribution of the stamp sands in Big Traverse Bay. • Ponar sampling – 2008-2013 • Light Detection and Ranging (LiDAR) and Multispectral Scanner (MSS) Studies Examine Coastal Environments Influenced by Mining – W. Charles Kerfoot 1,*, Martin M. Hobmeier 1, Foad Yousef 1, Sarah A. Green 1,2, Robert Regis 3, Colin N. Brooks 4, Robert Shuchman 3,4, Jamey Anderson 1 and Molly Reif 5 3.5 Mt 7.0 Mt 11.0 Mt Kerfoot et al. 2014 4 65 88 Big Traverse Bay Invertebrate Densities 2,000 Individuals/m2 1,800 1,600 Diporeia 1,400 Oligochaeta 1,200 Nematodae 1,000 Chironomidae 800 Sphaeriidae 600 Mysis 400 200 0 White Beach Natural White Beach Low Substrates Stampsand (up to 25%) Black Beach Low Stampsand (up to 25%) Black Beach Medium Stampsand (25-75%) Black Beach High Stampsand (75-100%) GLIFWC fish population assessments Traverse Bay • Beach seining – Conducted annually since 1997 during the summer months at various locations around the Keweenaw Peninsula. – Determine relative abundance of juvenile lake white fish. – Recently (2008, 2011, 2013) began sampling stamp sands area. – 100 ft or 50 ft in length, 4 ft height, 1/8th in. mesh. 2013 2011 2008 2008 CPE (n/100 ft haul) 70 Native sand Stamp sand CPE (n/100 ft haul) 60 50 Number of hauls on native sand = 4 Number of hauls on stamp sand = 4 40 30 20 10 0 SCP LWF STK Species STS 2011 CPE (n/100 ft haul) 10 CPE (n/100 ft haul) 9 8 Native sand 7 Stamp sand 6 5 4 3 Number of hauls on native sand = 8 Number of hauls on stamp sand = 2 2 1 0 ALE BIB CYP LWF PUS Species SCP SMT * TRP 2013 CPE (n/100 ft haul) 20 Native sand 18 Bedrock CPE (n/100 ft haul) 16 Stamp Sands 14 12 10 8 Number of hauls on native sand = 10 Number of hauls on bedrock = 3 Number of hauls on stamp sand = 5 6 4 2 0 RBT STS MEM BKT CMS CRC DAC NIS SCP BLG LOP MSC YEP Species Action • Army Corp of Engineers – Detroit district – Proposed construction of a 1.2 mile long stone wall to prevent further erosion of stamp sands pile. – ~$11 mil project cost. – Federal funds: Great Lakes Restoration Initiative (GLRI). – Matching funds being sought from Michigan Department of Environmental Quality (DEQ). Action • Cooperators: – Great lakes Indian Fish and Wildlife Commission – Michigan Technological University – Great Lakes Research Center – US Fish and Wildlife Service – Michigan Department of Natural Resources – Michigan Department of Environmental Quality – Keweenaw Bay Indian Community – Non Governmental Organizations Action • Feasibility study and modeling efforts underway and expected to be completed this year (2014). – Model the impact of the proposed wall. • Construction could begin as early as 2016. Conclusion • Stamp sands pose a threat to Buffalo Reef – Spawning fish – Benthos – Economic impacts • Restoration efforts important for rehabilitation of reef. • GLIFWC will continue to monitor fish population in Big Traverse Bay. Acknowledgements Bill Mattes – Great Lakes Indian Fish and Wildlife Commission Esteban Chiriboga – Great lakes Indian Fish and Wildlife Commission Charles Kerfoot – Michigan Technological University