Download Increased Role of Nearshore Zone for Lake Michigan Fish and

Increased Role of Nearshore Zone
for Lake Michigan Fish and Fisheries
Bo Bunnell1, Tomas Höök2, and Sergiusz Czesny3
1USGS
Great Lakes Science Center
2Purdue University, Dept. Forestry and Natural Resources
3Illinois Natural History Survey, Lake Michigan Filed Station
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
High
Low
total
phosphorus
1970
Great Lakes Water
Quality Agreement
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
1980
1990
Year
2000
2010
High
piscivore biomass
Sea lamprey control;
piscivore stocking
Low
total
phosphorus
1970
Great Lakes Water
Quality Agreement
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
1980
1990
Year
2000
2010
High
piscivore biomass
Low
Sea lamprey control;
piscivore stocking
total
phosphorus
spiny water flea
1970
1980
Great Lakes Water
Quality Agreement
2000
2010
Year
zebra mussel
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
1990
quagga mussel
round goby
Bunnell et al. 2014
Nearshore to offshore timeline
 1970s- higher nutrient loading. Relatively productive
nearshore, but without mussels nutrients were more
readily transported offshore.
1980s- reduced nutrient loading, piscivore build-up
complete. Differences between nearshore
productivity (high) and offshore productivity may be
lower.
2000s- “nearshore shunt”, “intermediate sink”
hypothesized to return nearshore to higher
productivity.
• Distribution and abundance of Cladophora and
dreissenid mussels from previous talks
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
Outline
1. Long-term perspective with USGS trawl data
2. Increasing role of nearshore contributions
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
Prey fish trends (5 – 114 m depth)
400
Ninespine stickleback
Deepwater sculpin
360
Rainbow smelt
Slimy sculpin
320
Lake-wide biomass (kt)
Round goby
Bloater
Alewife
280
240
200
160
120
80
40
0
1973
1978
1983
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
1988
1993
Year
1998
2003
2008
2013
Mechanisms driving the prey fish trends?
Top-down: Predation by salmonines prevents prey
fish from surviving to the ages they once enjoyed.
Bottom-up: Reduced prey densities (zooplankton,
Diporeia) lead to lower survival of age-0 fish or
slower growth and/or condition of juveniles and
spawning adults.
Today’s goal seeks to understand fish patterns from
a spatial perspective: how might differences in
nearshore vs. offshore habitat influence fish
production?
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
250
Nearshore
200
9, 18, 27 m
Mean = 27 kg/ha
150
50
0
Intermediate
200
150
100
37, 46, 55, 64, 73 m
Mean = 60 kg/ha
50
0
200
Offshore
82, 91, 110 m
Mean = 41 kg/ha
150
100
50
0
19
75
19
80
19
85
19
90
19
95
20
00
20
05
20
10
20
15
Total biomass (kg/ha + SE)
100
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
Nearshore community composition
100
90
Whitefish
80
Alewife &
Bloater
70
60
Kg/ha
Sucker
Stickleback
Smelt
Shad
Sculpin
Piscivore
50
Perch
Minnow
40
Goby
Drum
30
Catfish
Carp
20
Bloater
Alewife
10
0
1973
1978
1983
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
1988
1993
1998
2003
2008
2013
Intermediate community composition
180
160
Bloater &
Alewife
140
120
Kg/ha
Whitefish
Sucker
Stickleback
Smelt
Shad
Sculpin
100
Piscivore
Perch
80
Minnow
Goby
60
Drum
Catfish
40
Carp
Bloater
20
0
Alewife
1973
1978
1983
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
1988
1993
1998
2003
2008
2013
Offshore community composition
90
Sculpin,
Alewife &
Bloater
80
70
Kg/ha
60
Whitefish
Sucker
Stickleback
Smelt
Shad
Sculpin
50
Piscivore
Perch
40
Minnow
Goby
30
Drum
Catfish
20
Carp
Bloater
10
0
Alewife
1973
1978
Hook, Bunnell and
Czesny
1983
GLRRIN Lake Michigan Meeting April 2014
1988
1993
1998
2003
2008
2013
25
Nearshore
20
 Species richness is
highest in nearshore.
15
10
5
Intermediate
20
15
10
5
0
20
Offshore
15
10
5
0
19
75
19
80
19
85
19
90
19
95
20
00
20
05
20
10
20
15
Species richness
0
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
100
2004-2013 average
*100%
1973-2013 average
Nearshore
80
60
42%
20
0
100
Intermediate
80
60
40
12%
20
0
200
Offshore
150
100
36%
50
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
20
15
20
10
0
20
05
Total biomass (kg/ha + SE)
40
Since 2004,
nearshore fish
biomass is:
1) closer to longterm average
2) stable, if not
increasing.
Insights from long-term data
• Fish vulnerable to daytime bottom trawl has
declined at all depths.
 Effect of increasing water clarity?
 Effect of offshore fish moving deeper than
our survey samples?
• Since 2004, total biomass has declined the least
in the nearshore.
• Nearshore: highest species richness, but
richness has declined in 2000s.
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
Outline
1. Long-term perspective with USGS trawl data
2. Increasing role of nearshore contributions
1. Small-bodied fishes
2. Salmonines
3. Tributary and Wetland influences
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
Increasing
Trophic Position
Turschak, Bootsma et al. Ecology 2014
Food Web Shift
Offshore Energy
Sources
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
Nearshore Energy
Sources
2010-2011 Field collections
 2-hr bottom set, micromesh
gillnets
 3m, 7-9m, 14-16m
 Diets, fatty acids, isotopes
 Round goby, yellow perch,
spottail shiners and others
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
Round Goby Diets
n=58
n=36
n=110
n=132
n=26
n=17
n=34
 Dreissenids
 Rocky sites
 Larger fish
 Chironomids
 Always
important

Exception:
September
>100mm
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
n=114
n=30
Round goby diet ordination
 nMDS of site means
 Color = site









White = 6R
Red = 1R
Orange = 1S
Yellow = 2R
Green = 2S
Dark Green = 3R
Turquois = 3S
Blue = 4R
Dark Blue = 4S
Purple = 5R
 Symbol = season



Circle = May
Triangle = July
X = September
 Symbol Size = fish
length class



Small (<60mm)
Medium (60-100mm)
Large (>100mm)
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
1.5
1.0
0.5
0.0
MDS2

-0.5
-1.0
-1.5
-2.0
-2.5
-1.5
2D Stress:
0.09
-1.0
-0.5
0.0
0.5
MDS1
1.0
1.5
2.0
2.5
Round goby diet ANOSIM:
Seasons & Site Differences
 2010 60-100mm fish
 Sites 1R, 2R, 3R, and 4R
 2 factors

Season



Global test significant
(sample statistic = 0.1%)
All season pairwise
comparisons significant
Site


Global test significant
(sample statistic = 0.1%)
All site pairwise
comparisons with 4R
significant
 1R & 4R (R = 0.250),
2R & 4R (R = 0.395),
3R & 4R (R = 0.234)
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
2D Stress: 0.04
Round Goby Fatty Acid ANOSIM:
Seasons & Sites Different
 2010 60-100mm fish
 1R, 2R, 3R, 4R
 2 factors
Season
 Global test significant
(sample statistic = 0.1%)
 All season pairwise
comparisons significant
 Site
 Global test significant
(sample statistic = 0.1%)
 All pairwise comparisons
significant
 2R & 3R show the
strongest contrast for
adjacent sites (R =
0.682)
 Low site variation
between 1R & 2R, 3R &
4R
Hook, Bunnell and Czesny

GLRRIN Lake Michigan Meeting April 2014
2D Stress: 0.09
Round Goby Stable Isotopes:
60-100mm Round Goby
4R, 4S
3R, 3S, 5R
6R, 1R, 1S, 2R, 2S
Pelagic
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
Benthic
Spatial Variation in YOY YEP Fatty Acid Signatures - Fall
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
Happel et al.
Outline
1. Long-term perspective with USGS trawl data
2. Increasing role of nearshore contributions
1. Small-bodied fishes
2. Salmonines
3. Tributary and Wetland influences
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
Lake trout diets
Stomach Contents
Fatty acid analysis:
-Spatial patterns less evident
-Lake trout rely on both alewife
and goby
Hook, Bunnell and Czesny
GLRRIN
Michigan
Meeting April 2014
(McKenna
etLakeal.
in prep)
Chinook salmon increased their reliance on
alewife in 2009-2010 compared to 1994-1996
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
Jacobs et al. 2013
Alewife in 2009-2010 diets are smaller
than those in 1994-1996
1994-1996
2009-2010
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
Jacobs et al. 2013
Lake trout and rainbow trout harvest trends
in charter boat fishery: IL, MI and WI waters
(Lake Michigan, 1992-2012; N=~500K fishing trips)
Mean bathymetric depth (m)
75
65
Brown trout
55
Rainbow trout
r = -0.72
45
Lake trout
r = -0.68
35
25
1992
Chinook salmon
1997
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
2002
Year
2007
2012
Coho salmon
Simpson, Honsey, Rutherford, Höök unpubl.
Outline
1. Long-term perspective with USGS trawl data
2. Increasing role of nearshore contributions
1. Small-bodied fishes
2. Salmonines
3. Tributary and wetland influences
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
Comparison between drowned-rivermouth-lakes and nearshore Lake
Michigan as alewife nursery habitats
(2001-2003).
Höök et al. 2007, 2008
Dufour et al. 2005, 2008
Höök and Pothoven 2009
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
Contributions from other nearshore habitats
• As overall productivity of Lake Michigan has decreased,
we might expect that relative contributions of fish
(biomass, numbers, diversity) from distinct, productive
nearshore habitats to have increased.
• Several recent/on-going studies in Lake Michigan: river mouths (e.g., Larson
et al. 2012, 2013); drowned river mouth lakes (e.g., Janetski et al. 2013;
Bhagat and Ruetz 2011) coastal wetlands (e.g., Cooper et al. 2012); large bays
(e.g., Madenjian et al. 2011); river plumes (Höök, Troy et al.)
• Compared to Lake Michigan proper, these habitats provide differential prey
sources, growth rates, reproductive opportunities, etc.
• What is the overall role of these habitats at a system-wide scale?
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014
Increasing role of nearshore contributions
• Increased reliance on nearshore carbon (2002 vs 2010-12)
• Nearshore fishes
• Spatial trophic patterns
• east=pelagic
west=benthic
• Salmonines
• Species differences
• Chinook increased reliance on alewife
• Lake trout diverse diets; spatial differences
• Harvest shifted to shallower depths
• Other nearshore habitats
• Expectation of increased contribution from productive habitats
Hook, Bunnell and Czesny
GLRRIN Lake Michigan Meeting April 2014