AQUATIC EXOTICS

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AQUATIC EXOTICS
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Exxon Valdez Oil Spill Valdez, Alaska 1989
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By the end of the 21st century, biological
invasions will become one of the most
prominent ecological issues on Earth. OTA
Report (1993)
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OTA Report

• gt 4,500 species established
• gt 205 species arrived since 1980
• 59 might cause damage
• Control costs will approach 100 billion

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Infestations Are Increasing
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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

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Great Lakes Exotics

• Purple loosestrife
• Zebra mussel
• Quagga mussel
• Spiny waterflea
• Fishhook waterflea

• Eurasian ruffe
• Round goby
• Alewife
• Trout and salmon

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Where Did They Come From?

• Eurasia 77
• Atlantic 18
• Asia 12
• Mississippi 7
• Pacific/Southern U.S. 7
• Unknown 18
• Total 139

• (data taken from Mills et al. 1993)

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How Did They Get Here?

• Ships 41
• Unintentional release 40
• Multiple 27
• Unknown 14
• Deliberate release 11
• Canals 5
• Railroad/Highway 1

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• (data taken from Mills et al. 1993)

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What Are They?

• of Species
• Plants (mostly marsh) 42
• Invertebrates 21
• Fish 18
• Algae 17
• Fish pathogens 2

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• (data taken from Mills et al. 1993)

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• The Good
• The Bad
• The Ugly

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The Good
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The Bad
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Adult
Can produce up to 1.6 M eggs/yr!
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Zebra mussel colony
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Byssal threads
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Impacts of Zebra Mussels

• Feed by filtering particles from water
• Each adult can filter 1 L water/day

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Impacts of Zebra Mussels

• Increase weed growth
• Disrupt food webs

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Impacts of Zebra Mussels
Clogged pipe
Fouled boat
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Impacts of Zebra Mussels

• Control costs in the Great Lakes 120 million
  from 1989 - 1994

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Impacts of Zebra Mussels
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Zebra Mussel Distribution

• Spread as larvae and adults
• Only 10 states with inland infested waters
  

(WI, MI, MN, PA, IL, IN, OH, NY, CT, VT)
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Quagga Mussel Distribution

• Lakes Erie, Ontario and Michigan
• Ohio and Mississippi rivers

(WI, MI, IL, IN, OH, NY, CT, VT)
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ID and Early Detection

• Newly settled mussels feel like fine sand paper
• Grow to look like coarse grains of pepper

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• Cause serious damage
• Industrial control is costly
• No method of control in natural ecosystems
• Preventing the spread is critical

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Rusty Crayfish

• Replaces native crayfish
• Competes with fish
• Raids fish nests
• Eradicates aquatic plants

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U.S. Distribution
Drainages with native populations Drainages with
introduced populations
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Rusty Crayfish Spread

• Anglers and commercial harvesters
• Ballast water
• Biological supply houses schools
• Life history facilitates spread

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Rusty Crayfish ID

• Can grow up to 8 in
• Rust spots on carapace
• Large gray-green/red-brown claws

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Rusty Crayfish

• No environmentally-friendly control method
• Preventing the spread is critical

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Round Goby

• Small, strange-looking bottom fish
• Came from Eurasia in ballast water
• Considered a nuisance by anglers

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Round Goby Impacts
mottled sculpin

• Out-compete native species
• Quickly dominate local fisheries

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Round Goby Impacts

• Feed on lake trout and sturgeon eggs

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Round Goby Identification

• Fused pelvic fins

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Eurasian Watermilfoil

• Forms dense mats
• Replaces native plants
• Degrades food, shelter, and nesting sites for
  fish
• Limits swimming and boating

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Eurasian Watermilfoil

• Spreads by fragmentation

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Eurasian Watermilfoil

• Can be spread by recreational water users

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U.S. Distribution
Adapted 1999 from USGS-Gainesville
States with nonnative records
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Optimistic News

• Traditional control methods costly
• Native weevil feeds on Eurasian watermilfoil
• Can cause stems to fall to lake bottom
• Reduces canopy

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• Spiny Waterflea

• Predaceous zooplankton
• Causes declines in native zooplankton
• May impact fisheries

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Fishhook waterflea
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Eurasian Ruffe

• Arrived in mid 1980s via ballast water

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Eurasian Ruffe

• Spawn 2 3 times/season
• Mature rapidly
• Feed during day and night

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Eurasian Ruffe Impacts

• May compete with yellow perch

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Predicted impacts of Great Lakes-wide
infestation is estimated at 105 million annually
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White Perch

• Native to Atlantic coast
• Found in all Great Lakes
• Feed on zooplankton, invertebrates, and fish
• Prefer shallow areas

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White Perch
white perch
white bass

• Easily confused with native white bass
• Transported to several inland lakes in Ohio

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White Perch

• Can grow up to 10 long
• Commonly stunted and undesired by anglers
• Can have high levels of PCBs

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Threespine Stickleback

• Native to Hudson Bay, the Atlantic coast, and
  Lake Ontario
• Spread to lakes Superior, Michigan, and Huron
• Little known about potential impacts

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Threespine Stickleback
Fourspine Stickleback

• May compete with native sticklebacks
• 3 or 4 spines on dorsal fin, respectively
• Native sticklebacks have 5 or more spines on
  dorsal fin

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Purple Loosestrife

• Perennial from Europe
• Invades moist areas
• Crowds out nativesreduces biodiversity

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U.S. Distribution
Adapted 1999 from Biological Invasions by GLP
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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

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We can make a difference!
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Three-State Exotic Species Boater Survey

• How best to reach boaters
• Determine if boaters taking action

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Source For Exotics Information

• Newspaper 92 81 84
• Television 90 79 73
• Magazine 75 67 74
• Boat Launch 82 55 32

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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

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What Influenced You Most?
Minn
Wisc
Ohio

• Out of My Lake 88 74 63
• Personal Responsibility 82 63 56
• Signs at Access 68 47 31
• Prevent Property Damage 38 43 55

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Why Didnt You Take Precautions?
Not a Problem
Didnt Boat in Infested Waters
Didnt Know What To Do
Didnt Have Time
It Wont Help
Percent response
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What Works?
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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

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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

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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

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Prevent the Spread

• BEFORE launching.. BEFORE leaving
• Remove aquatic plants and animals.
• Drain lake or river water.
• Dispose of unwanted live bait.
• Rinse equipment with high pressure or 104 F
  water. OR
• Dry everything for at least 5 days.

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• 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.
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