Transcript Lake Erie Hypoxia: History and Management Response

Lake Erie Hypoxia: History and
Management Response
Stuart A. Ludsin
NOAA Great Lakes Environmental Research Laboratory
Ann Arbor, MI
Roger L. Knight
Ohio Department of Natural Resources
Division of Wildlife
Sandusky, OH
Presentation Outline
• Lake Erie hypoxia
• Lake Erie’s fisheries
• Hypoxia effects on fisheries
• Ongoing research
Lake Erie Facts
MI
ON
N
W
S
Ian.umces.edu/symbols
OH
 Small
 Shallow
 Warm
 Productive
E
Volume = 484 km3
Depth = 19 m
> 200 Frost Free Days
All Trophic Levels
East
Periodic
hypoxia
West
Central
Annual
hypoxia
Depth (m)
0
Cool
Warm epilimnion
20
40
Cool hypolimnion
(hypoxic during summer)
60
Source: Murray Charlton, NWRI
High
Temperature
Productivity
Low
Max.
Hypoxic (< 2 mg/l)
Area = 10,000 km2
Central Lake Erie Hypoxia
Source: Paul Horvatin, US EPA-GLNPO
Lake Erie Hypoxia
• Hypoxia is “natural”
– Lake Erie – present 100s to 1000s of yrs ago
– Due to central basin bathymetry
• Nutrient (phosphorus, P) inputs also important
– 1950s-1970s:  point-source loading,  hypoxia
– 1980s-1990s:  point-source loading,  hypoxia
– 2000-present:  non-point source loading,  hypoxia
Presentation Outline
• Lake Erie hypoxia
• Lake Erie’s fisheries
• Hypoxia effects on fisheries
• Ongoing research
Lake Erie’s Fisheries
• Numerous recreational & commercial fisheries
– Billion-dollar per year fishery (during mid-1980s)
Millions of Pounds
40
Walleye
Yellow perch
30
(www.buckeyeangler.com)
(©Shedd Aquarium)
20
10
Yellow
Perch
Walleye
0
1915 1925 1935 1945 1955 1965 1975 1985 1995
Central Lake Erie Food Web
Burbot
Piscivorous
Fish
(www.gov.mb.ca)
Walleye
(www.buckeyeangler.com)
Yellow perch
(©Shedd Aquarium)
White perch
Benthivorous
Fish
Planktivorous
Fish
Emerald shiner
(www.cnr.vt.edu)
(www.cnr.vt.edu)
Rainbow smelt
(nas.er.usgs.gov)
Lake whitefish
(www.gov.mb.ca)
Benthic
Macroinverts.
Zooplankton
Presentation Outline
• Lake Erie hypoxia
• Lake Erie’s fisheries
• Hypoxia effects on fisheries
• Ongoing research
Hypoxia Effects on Fisheries
• Lake Erie Fish Community
– 1950s-1970s:  hypoxia,  lake whitefish & burbot (Leach &
Nepszy 1976)
•  thermal & foraging habitat
•  vulnerability to commercial fishing (aggregation effect)
– 1980s-1990s:  hypoxia,  lake whitefish, burbot,
smallmouth bass & silver chubs (Ludsin et al. 2001)
– A word of caution is needed
• Leach & Nepszy (1976)…speculation only
• Ludsin et al. (2001)…based on time-series correlations
– confounding factors: harvest, climate, exotic species
– Until 2005, no mechanistic hypoxia-fisheries work
Reduced Phosphorus Inputs
(A Management Dilemma)
-
+
Walleye &
yellow perch
Oxygen &
minor fisheries
Ludsin et al. (2001)
Presentation Outline
• Lake Erie hypoxia
• Lake Erie’s fisheries
• Hypoxia effects on fisheries
• Ongoing research
International Field Years on Lake Erie (IFYLE)
Program
(www.IFYLE.org)
- Stuart Ludsin & Stephen Brandt, project co-leaders
- 45 PIs, 18 institutions
- Field years: 2005, 2007, 2008-2009
- 130 ship days, >2,000 people-days at “sea” in 2005
IFYLE Program
• Primary Research Goal
– Understand ecological consequences of hypoxia
• Trophic interactions, growth, condition, recruitment
• Ultimate Research Goal
– Help agencies understand if they should care about
hypoxia when managing fisheries
• IFYLE data will be presented here
– Höök, Vanderploeg, Lavrentyev
Forecasting the Causes, Consequences, and
Potential Solutions for Hypoxia in Lake Erie
• Project Leader: Don Scavia
• NOAA-ECOFORE Program funding, 2006-2011
• 19 PIs, 8 institutions
- Primarily NOAA-GLERL & U of Michigan scientists
• Modeling effort  means to integrate & synthesize
IFYLE data
• Provide understanding, predictive capabilities, and
recommendations to benefit management
Thanks for your attention
Hypoxia Effects on Fisheries
Production or Fishery Yield
2000
1950s-1970s
(Ludsin et al. 2001)
1950s-1970s
(Leach & Nepszy 1976)
Planktivorous
Fish
Lake
whitefish
& burbot
Benthic
Fish
Benthos
Hexagenia
spp.
Oligo-
Meso-
Eu-
Trophic state
HyperModified from Caddy (1990)
Hypoxia Effects on Fisheries
• Alteration of nutrient inputs
Relative abundance
– Hypoxia likely playing some role
1990-2000
Pre-1950
1977-1987
1955-1970
1970s
1970s
Coregonids
(lake whitefish)
Percids
(yellow perch)
Cyprinids
(common carp)
Leach et al.
(1972)
Ludsin et al.
(2001)
Oligotrophy
(low nutrients)
Eutrophy
(high nutrients)