let’s prevent a flea circus: stopping minnesota’s invasion by … · hatch partial hatch 9...
TRANSCRIPT
Let’s Prevent a Flea Circus: Stopping Minnesota’s Invasion by Spiny Water Flea
Donn K. Branstrator (University of Minnesota Duluth) [email protected]; 218-726-8134
September 12, 2016
1 cm
Native
Believed vector - cargo ship ballast water from Baltic Sea.
First appearance in North America - 1980s in Great Lakes.
Non-native
Kerfoot et al. (2011)
Now spread to 150-200 inland lakes.
About 35 Minnesota lakes infested
Minnesota Invasion Timeline
Year
1990 1995 2000 2005 2010 2015
0
10
20
30
40
Cum
ula
tive n
um
be
r of
invaded lakes
6 of top 10 largest inland lakes
Presentation Outline
A) Bythotrephes biology
B) Management-relevant research on mitigating spread 1) What we know (completed project)2) What we don’t know (future project)
C) Management-relevant research on ecosystem impacts
Bythotrephes longimanus
1) Bythotrephes is neither a flea nor an insect.
Crustacean : Freshwater and marine group that includes crayfish and shrimp.
Freshwater Zooplankton: Small-bodied animal that lives in the open waters of lakes.
2) Bythotrephes’ long, stiff tail spine is a novelty among freshwater zooplankton in North America.
Fish < 10 cm body length have trouble eating Bythotrephes.
Larger fish eat Bythotrephes but the spine may slow gut passage and injure gut lining.
Cisco Stomach Photo by B. Clarke
3) Bythotrephes’ reproductive strategy is seasonally adaptive.
For most of the summer, females produce females through clonal (asexual) reproduction.
1-2 weeks to go from egg to egg
Stage 1 Stage 2 Stage 3
Gravid female A single female could theoretically colonize a new lake.
In the fall, females make males and mate with them. The result is a resting egg that lies dormant during winter months, and hatches the subsequent spring.
Phytoplankton
Bythotrephes
Planktivorous
Fish
Piscivorous
Fish
Herbivorous
Zooplankton
4) Bythotrephes is a carnivore that disrupts food webs at mid trophic levels; how does this cascade to
other trophic levels?
In lakes of Voyageurs National Park, herbivorous zooplankton biomass declined 40-60% after Bythotrephesinvaded (Kerfoot et al. 2016 ).
?
?
40-60%
A) Bythotrephes biology
B) Management-relevant research on mitigating spread 1) What we know (completed project)2) What we don’t know (future project)
C) Management-relevant research on ecosystem impacts
Bythotrephes longimanus
3-Step Firewall
Small and cryptic nature places premium on
drying
Harvest resting eggs (Sep-Oct) from wild-caught females.
1) Apply Stressor - 48 eggs per treatment (about 5,000 eggs over 3 years) – mimic a decontamination event
2) 4 month incubation simulating winter (dark, 3-4°C)
3) Temperature cue simulating spring overturn
4) Score hatching after 5 more months.
General Experimental Protocol to Test Drying and Other Stressors
Hatch
Partial hatch
9 months to complete an experimental
trial
Perc
enta
ge h
atc
h o
r part
ial hatc
h
0 15 25 35
2 weeks exposure
4 weeks exposure
Salinity (ppt)
control
control
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80
100
SalinityOcean water
concentration is non-lethal.
Hatch
Partial hatch
0
Chlorine (ppm)
Perc
enta
ge h
atc
h o
r part
ial hatc
h
1 hour
no
data
controlcontrol
no
data
5 mincontrolcontrol
controlcontrol
1 min
no
data
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0 1 500 3,400
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0 0 1 500 3,400
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1 day
no
data
controlcontrol
Chlorination
Recipe strength on CLOROX container is
non-lethal.
Hatch
Partial hatch
0
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80
100
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100
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Perc
enta
ge h
atc
h o
r part
ial hatc
h
Temperature (°C)
10 min
5 min
1 min
4 40 50
control
control
control
*
Heat
Hatch
Partial hatch
Implications for:
- Clean, drain, dry (50°C)
- Avian vectors (40°C body temperatures).
The lethal exposure is between 40-50 C for longer than 1 minute.
0
20
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100
Perc
enta
ge h
atc
h o
r part
ial hatc
h
0 0 0.5 1 3 6 8 10 12 24
Drying time (hours)
2 4
Drying
Short-term drying works.Hatch
Partial hatch
We don’t know which recreational pathways pose the highest risk to overland transport.
Understanding the relative risks of angling equipment, watercraft hulls, anchors, versus live wells may improve the outreach message.
We don’t know if lake usage during different periods of day poses different risks of transfer.
Day versus night
0.03 0.06 0.09 0.12 0.150.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15
0.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15
2200 h
0
2
4
6
8
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12
Dep
th (
m)
0.00 0.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15
1000 h 1400 h 1800 h
200 h
0.03 0.06 0.09 0.12 0.15
600 h
Number L-1
0
2
4
6
8
10
12
0.00 0.03 0.06 0.09 0.12 0.15
Dep
th (
m)
0.03 0.06 0.09 0.12 0.15 0.06 0.12 0.18 0.24 0.30
Number L-1
0
2
4
6
8
10
12
0.00 0.03 0.06 0.09 0.12 0.15
Dep
th (
m)
0.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15 0.03 0.06 0.09 0.12 0.15
Number L-1
0
0
50
0
0
0
100
0
28
40
0
0
0
0
25
0
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50
0
0
100
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50
0
0
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100
0
0
0
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25
100
100
0
0
67
0
0
20
28
0
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0
100
100
100
0
0
100
100
0
25
0
0
67
0
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100
100
67
50
50
100
0 20 40 60 80 100
0 20 40 60 80 100
0 20 40 60 80 100
% Surface Irradiance
Stage 1
Stage 2
Stage 3
July 14-15
Increased Export Risk
August 27-28
September 2-3
Increased Export Risk
Increased Export Risk
Island Lake Reservoir, Duluth, Minnesota, 2004
A) Bythotrephes biology
B) Management-relevant research on mitigating spread 1) What we know (completed project)2) What we don’t know (future project)
C) Management-relevant research on ecosystem impacts
Bythotrephes longimanus
• Collect and section sediment core.• Date core sections (Lead-210).• Reconstruct past food web based on zooplankton subfossil remains.
What are the long-term impacts (magnitude and timing) of Bythotrephesinvasion on zooplankton, phytoplankton, and fish?
Paleolimnology
47.00
47.05
Longitude (oW)
Lat
itu
de
(oN
)
92.20 92.15 92.10
1
2
N
3
4
1 km
°
In 2009-2010 we studied sediment cores from Island Lake Reservoir, Duluth.
0
1000
2000
3000
4000
1970 1980 1990 2000 20100
1000
2000
3000
4000
Site 1
Site 2
Site 3
1970 1980 1990 2000 2010
Site 4
B. lo
ng
ima
nu
s a
ccu
mu
latio
n
rate
(sp
ine
s m
-2y
-1)
Estimated Year (210Pb)
Bythotrephes was first detected by anglers in 1990.
Bythotrephes was first present in the sediments in 1982.
Site 2
D. retrocurva
D. pulex
D. mendotae
1970 1980 1990 2000 2010
Daphnia
spp.
accum
ula
tion r
ate
(ephip
pia
m-2
y-1
)
Estimated Year (210Pb)
6000
4000
2000
0
Prey of Bythotrephes shifted in species composition but not until Bythotrephesreached a carrying capacity (about 15 years post-invasion).
Phytoplankton
Bythotrephes
Planktivorous
Fish
Piscivorous
Fish
Herbivorous
Zooplankton
How do changes wrought by Bythotrephes cascade to higher and
lower trophic levels in Minnesota lakes, and what is the timing of these events?
MAISRC funded paleolimnology project collaborative with the Minnesota DNR (fish data).
Study lakes:Kabetogama *Infested 2007Mille Lacs *Infested 2009Leech *Non-infested Winnibigoshish *Non-infested
?
?
AcknowledgementsAshley BeranekMeghan BrownDan EngstromKatie HeimgartnerLeif HembreMarte KitsonAmy MyrboEuan ReavieDoug RickettsLyle ShannonMike SorensenMatt TenEyck