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AQUATIC EXOTICS
1
Exxon Valdez Oil SpillValdez, Alaska 1989
2
“By the end of the 21st century, biological invasions will
become one of the most prominent ecological issues on Earth.”
OTA Report (1993)
3
• > 4,500 species established
• > 205 species arrived since 1980
• 59 might cause damage
• Control costs will approach $100 billion
4
OTA Report
Infestations Are Increasing
5
Interrupt the Pathways
Shipping and barge traffic Aquaculture and public stocking Wild bait harvest Recreational boats Live bait Nursery trade and aquascaping Aquarium and pet trade
6
Great Lakes Exotics
• Purple loosestrife• Zebra mussel • Quagga mussel• Spiny waterflea• Fishhook waterflea
• Eurasian ruffe• Round goby• Alewife • Trout and salmon
7
Eurasia 77
Atlantic 18
Asia 12
Mississippi 7
Pacific/Southern U.S. 7
Unknown 18
Total: 139
Where Did They Come From?
8(data taken from Mills et al. 1993)
Ships 41
Unintentional release 40
Multiple 27
Unknown 14
Deliberate release 11
Canals 5
Railroad/Highway 1
How Did They Get Here?
9(data taken from Mills et al. 1993)
% of Species
Plants (mostly marsh) 42
Invertebrates 21
Fish 18
Algae 17
Fish pathogens 2
What Are They?
10(data taken from Mills et al. 1993)
11
Why Do Exotics Cause Problems?
Aggressive and prolific
Mature quickly
Leave behind diseases, parasites, predators, and competitors
The Good
The Bad
The Ugly
12
The Good
13
14
The Bad
15
Adult Veliger
Can produce up to 1.6 M eggs/yr!
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Zebra mussel colony
Byssal
threads
17
18
Impacts of Zebra Mussels
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• Feed by filtering particles from water• Each adult can filter 1 L water/day
Impacts of Zebra Mussels
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• Increase weed growth• Disrupt food webs
Clogged pipeClogged pipe
21
Fouled boat
Impacts of Zebra Mussels
22
Impacts of Zebra Mussels
Control costs in the Great Lakes = $120 million from 1989 - 1994
23
Impacts of Zebra Mussels
2424
Spread as larvae and adults
Only 10 states with inland infested waters
Zebra Mussel
Distribution
25
(WI, MI, MN, PA, IL, IN, OH, NY, CT, VT)
Lakes Erie, Ontario and Michigan
Ohio and Mississippi rivers
Quagga Mussel Distribution
26
(WI, MI, IL, IN, OH, NY, CT, VT)
ID and Early Detection
Newly settled mussels feel like fine sand paper
Grow to look like coarse grains of pepper27
Cause serious damage
Industrial control is costly
No method of control in natural ecosystems
Preventing the spread is critical28
Rusty Crayfish
• Replaces native crayfish• Competes with fish• Raids fish nests• Eradicates aquatic plants 29
U.S
. Dis
trib
uti
on
30
Drainages with native populations
Drainages with introduced populations
Drainages with native populations
Drainages with introduced populations
• Anglers and commercial harvesters• Ballast water• Biological supply houses & schools• Life history facilitates spread
31
Rusty Crayfish Spread
Rusty Crayfish ID
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• Can grow up to 8 in
• Rust spots on carapace
• Large gray-green/red-brown claws
33
Rusty Crayfish
• No environmentally-friendly control method
• Preventing the spread is critical
Round Goby
• Small, strange-looking bottom fish
• Came from Eurasia in ballast water
• Considered a nuisance by anglers34
Round Goby Impacts
mottledsculpin
• Out-compete native species
• Quickly dominate local fisheries
35
Round Goby Impacts
• Feed on lake trout and sturgeon eggs
36
37
• Fused pelvic fins
Round Goby Identification
38
Eurasian Watermilfoil
• Forms dense mats
• Replaces native plants
• Degrades food, shelter, and nesting sites for fish
• Limits swimming and boating 39
• Spreads by fragmentation
40
Eurasian Watermilfoil
• Can be spread by recreational water users
41
Eurasian Watermilfoil
U.S
. Dis
trib
uti
on
42
Adapted 1999 from USGS-Gainesville
States with nonnative recordsStates with nonnative records
Optimistic News
• Traditional control methods costly• Native weevil feeds on Eurasian watermilfoil
– Can cause stems to fall to lake bottom– Reduces canopy
4343
Predaceous zooplankton
Causes declines in native zooplankton– May impact fisheries
44
Spiny Waterflea
45
4646
Fishhook waterfleaFishhook waterflea
4747
Eurasian Ruffe
• Arrived in mid 1980s via ballast water
48
• Spawn 2 – 3 times/season
• Mature rapidly
• Feed during day and night
Eurasian Ruffe
49
Eurasian Ruffe Impacts
50
• May compete with yellow perch
Predicted impacts of Great Lakes-wide infestation is
estimated at $105 million annually
51
*
52
White Perch
• Native to Atlantic coast
• Found in all Great Lakes
• Feed on zooplankton, invertebrates, and fish• Prefer shallow areas
53
White Perch
• Easily confused with native white bass
• Transported to several inland lakes in Ohio
54
white perch white bass
White Perch
• Can grow up to 10” long• Commonly stunted and undesired by anglers• Can have high levels of PCBs
55
Threespine Stickleback
• Native to Hudson Bay, the Atlantic coast, and Lake Ontario
• Spread to lakes Superior, Michigan, and Huron
• Little known about potential impacts56
Threespine Stickleback
• May compete with native sticklebacks
• 3 or 4 spines on dorsal fin, respectively– Native sticklebacks have 5 or more spines
on dorsal fin
57
Fourspine Stickleback
58
Purple Loosestrife
• Perennial from Europe
• Invades moist areas
• Crowds out natives—reduces biodiversity
U.S
. Dis
trib
uti
on
59
Adapted 1999 from Biological Invasions by GLP
Good News!!
• 5 species approved for release
• Galerucella weevil– Feeds on leaves and growing shoots– Defoliates, reduces flowering, can kill plant
• Releases could reduce loosestrife by 80-90%60
We can make a difference!
61
Three-State Exotic Species Boater Survey
62
• How best to reach boaters
• Determine if boaters taking action
Source For Exotics Information
• Newspaper 92 81 84• Television 90 79 73• Magazine 75 67 74• Boat Launch 82 55 32
Minn Wisc Ohio
63
How Effective Are The Following?
• Signs at Accesses 77 62 50• In Fish/Boat Regs 63 60 59• Brochures 61 57 58 • Inspection/Ed 63 52 48
Lowest Ranked • Laws 53 41 34• Road Checks 48 29 24
Minn Wisc OhioHighest Ranked
64
What Influenced You Most?
• Out of “My” Lake 8888 7474 6363
• Personal Responsibility 82 63 56
• Signs at Access 68 47 31
• Prevent Property Damage 38 43 55
MinnMinn WiscWisc OhioOhio
65
Why Didn’t You Take Precautions?
0 10 20 30 40 50
OhioWiscMinn
Not a Problem
Didn’t Boat in Infested Waters
Didn’t Know What To Do
Didn’t Have Time
It Won’t Help
Percent response 66
What Works?
67
Survey Conclusions
• Boater education changes behavior
• Boaters believe it is important to prevent the spread of aquatic exotics
• Best information outlets are media, access signs, brochures, fishing and boating pamphlets
• Educational efforts must continue
68
Education Works
Rate of inland lake zebra mussel infestations is slowing
Eurasian watermilfoil infestation rate has slowed
Eurasian ruffe have not spread to inland lakes
Round goby spread to inland waters is limited
69
Prevent the Spread
• Know how to identify exotics
• Know which waters are infested
• Know the laws concerning prohibited exotics
• Learn the five simple steps to prevent spread
70
Prevent the Spread
71
BEFORE launching….. BEFORE leaving
1. Remove aquatic plants and animals.
2. Drain lake or river water.
3. Dispose of unwanted live bait.
4. Rinse equipment with high pressure or 104 F water.
OR
5. Dry everything for at least 5 days.
72
73
Written and produced by
Doug Jensen and Jeff Gunderson
2001
With support from:
Editors: Glenn Kreag, Sharon Moen, Marie Zhuikov, and Pat Charlebois
Digital Production Coordinator: Debbie Bowen
Funding for this project was provided by a grant from the U.S. National Oceanic Administration to the National Sea Grant College Program through an
appropriation by Congress based on the National Invasive Species Act of 1996.