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

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