AQUATIC EXOTICS 1. Exxon Valdez Oil Spill Valdez, Alaska 1989 2.

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  • Exxon Valdez Oil SpillValdez, Alaska 1989*

  • By the end of the 21st century, biological invasions will become one of the most prominent ecological issues on Earth.OTA Report (1993)


  • > 4,500 species established

    > 205 species arrived since 1980

    59 might cause damage

    Control costs will approach $100 billion*OTA Report

  • Infestations Are Increasing*

  • Interrupt the PathwaysShipping and barge trafficAquaculture and public stockingWild bait harvestRecreational boats Live baitNursery trade and aquascapingAquarium and pet trade6

  • Great Lakes ExoticsPurple loosestrifeZebra mussel Quagga musselSpiny waterfleaFishhook waterfleaEurasian ruffeRound gobyAlewife Trout and salmon7

  • Eurasia77Atlantic18Asia12Mississippi 7Pacific/Southern U.S. 7Unknown18 Total: 139 Where Did They Come From?8(data taken from Mills et al. 1993)

  • Ships41Unintentional release40Multiple27Unknown14Deliberate release11Canals 5Railroad/Highway 1How Did They Get Here?9(data taken from Mills et al. 1993)

  • % of SpeciesPlants (mostly marsh) 42Invertebrates21Fish18Algae17Fish pathogens 2 What Are They?10(data taken from Mills et al. 1993)

  • *

  • The Good

    The Bad

    The Ugly*

  • The Good*

  • *The Bad

  • *AdultCan produce up to 1.6 M eggs/yr!

  • *Zebra mussel colony

  • Byssalthreads17

  • 18

  • Impacts of Zebra Mussels19 Feed by filtering particles from water Each adult can filter 1 L water/day

  • Impacts of Zebra Mussels20 Increase weed growth Disrupt food webs

  • Clogged pipe*Fouled boatImpacts of Zebra Mussels

  • Impacts of Zebra MusselsControl costs in the Great Lakes = $120 million from 1989 - 1994*

  • Impacts of Zebra Mussels*

  • *

  • Spread as larvae and adults

    Only 10 states with inland infested waters Zebra Mussel Distribution*(WI, MI, MN, PA, IL, IN, OH, NY, CT, VT)

  • Lakes Erie, Ontario and Michigan

    Ohio and Mississippi rivers Quagga Mussel Distribution26(WI, MI, IL, IN, OH, NY, CT, VT)

  • ID and Early DetectionNewly settled mussels feel like fine sand paper

    Grow to look like coarse grains of pepper*

  • Cause serious damage

    Industrial control is costly

    No method of control in natural ecosystems

    Preventing the spread is critical28

  • Rusty CrayfishReplaces native crayfish

    Competes with fish

    Raids fish nests

    Eradicates aquatic plants29

  • U.S. Distribution30Drainages with native populationsDrainages with introduced populations

  • Anglers and commercial harvesters

    Ballast water

    Biological supply houses & schools

    Life history facilitates spread*Rusty Crayfish Spread

  • Rusty Crayfish ID32 Can grow up to 8 in Rust spots on carapace Large gray-green/red-brown claws

  • 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 ImpactsOut-compete native species

    Quickly dominate local fisheriesmottledsculpin*

  • Round Goby ImpactsFeed on lake trout and sturgeon eggs*

  • 37

  • Fused pelvic finsRound Goby Identification38

  • Eurasian Watermilfoil Forms dense mats

    Replaces native plants Degrades food, shelter, and nesting sites for fish

    Limits swimming and boating39

  • Spreads by fragmentation40Eurasian Watermilfoil

  • Can be spread by recreational water users41Eurasian Watermilfoil

  • U.S. Distribution*Adapted 1999 from USGS-GainesvilleStates with nonnative records

  • Optimistic NewsTraditional control methods costlyNative weevil feeds on Eurasian watermilfoilCan cause stems to fall to lake bottomReduces canopy*

  • Spiny WaterfleaPredaceous zooplankton

    Causes declines in native zooplanktonMay impact fisheries 44

  • 45

  • 46

  • Fishhook waterflea47

  • Eurasian RuffeArrived in mid 1980s via ballast water48

  • Spawn 2 3 times/seasonMature rapidlyFeed during day and nightEurasian Ruffe49

  • Eurasian Ruffe Impacts50 May compete with yellow perch

  • Predicted impacts of Great Lakes-wide infestation is estimated at $105 million annually51

  • *52

  • White PerchNative to Atlantic coast Found in all Great Lakes Feed on zooplankton, invertebrates, and fish

    Prefer shallow areas53

  • White PerchEasily confused with native white bass

    Transported to several inland lakes in Ohio 54white perchwhite bass

  • White PerchCan grow up to 10 longCommonly stunted and undesired by anglersCan have high levels of PCBs*

  • Threespine SticklebackNative to Hudson Bay, the Atlantic coast, and Lake Ontario

    Spread to lakes Superior, Michigan, and Huron

    Little known about potential impacts56

  • Threespine SticklebackMay compete with native sticklebacks

    3 or 4 spines on dorsal fin, respectivelyNative sticklebacks have 5 or more spines on dorsal fin57Fourspine Stickleback

  • 58Purple Loosestrife Perennial from Europe Invades moist areas Crowds out nativesreduces biodiversity

  • U.S. Distribution59Adapted 1999 from Biological Invasions by GLP

  • Good News!!5 species approved for releaseGalerucella weevilFeeds on leaves and growing shootsDefoliates, reduces flowering, can kill plantReleases 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 InformationNewspaper 92 81 84Television 90 79 73Magazine 75 67 74Boat Launch 82 55 3263

  • How Effective Are The Following?Signs at Accesses77 62 50In Fish/Boat Regs 63 60 59Brochures6157 58 Inspection/Ed635248

    Lowest Ranked Laws534134Road Checks 48292464

  • What Influenced You Most?Out of My Lake 887463Personal Responsibility826356Signs at Access684731Prevent Property Damage384355MinnWiscOhio65

  • Why Didnt You Take Precautions?Not a ProblemDidnt Boat in Infested WatersDidnt Know What To DoDidnt Have TimeIt Wont HelpPercent response66

  • What Works?67

  • Survey ConclusionsBoater 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 continue68

  • Education WorksRate 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 limited69

  • 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


  • Prevent the SpreadBEFORE 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.71

  • 72

  • Written and produced byDoug Jensen and Jeff Gunderson2001 With support from:

    Editors: Glenn Kreag, Sharon Moen, Marie Zhuikov, and Pat Charlebois

    Digital Production Coordinator: Debbie Bowen73Funding 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.

    Aquatic exotics are causing serious ecological and economic damage to our nation damage that could be happening right in your own backyard. During this presentation youll learn about the problems these invasive fish, aquatic invertebrates, and aquatic plants are causing. You'll also learn what you can do to prevent their spread and limit their impacts.

    The invasion of aquatic exotic species has been likened to biological pollution, which in turn is similar to chemical pollution. Both cause huge amounts of damage, require treatment, and can spread beyond the initial point of release, like the Exxon Valdez oil spill in 1989. Unlike chemical pollution, though, biological pollution is forever. In one of his speeches, former Senator John Glenn illustrated the comparison, Picture a pollution spill in the waters of your region that simply wont go away. Government and industry teams work to disperse it with chemicals and mechanical barriers, but as soon as the treatments stop, the pollution resurges. Worse yet, the spill spreads and concentrates in connecting waterways and is further seeded by unintentional transport overland. Municipalities, manufacturers, and agriculture experience degraded water supplies and higher operating costs. Shell-fisheries and fin-fisheries permanently decline. This scenario sounds like a nightmare, yet it closely approximates the result of unintentional release of nonindigenous species, or biological pollution into U.S. waters.

    This problem of biological pollution is happening on a global scale. This was highlighted in a 1993 report to the U.S. Congress by the Office of Technology Assessment, or OTA. The OTA predicted that By the end of the 21st Century, biological invasions will become one of the most prominent ecological issues on Earth.

    According to that report, 4,500 aquatic and terrestrial species of foreign origin have established free-living U.S. populations. More than 205 species arrived since 1980, and 59 of these are expected to cause economic or environmental damage. Another, more recent report by researchers at Cornell University estimates that control costs for invasive terrestrial and aquatic species exceed 138 billion dollars annually.

    Not only have we been invaded by thousands of species, there is evidence that the infestation rate is increasing. The OTA report shows that the rate of fish introductions has dramatically increased since 1950, while the rate of introductions of mollusks or clams began increasing earlier, in the 1920s. Few of these invaders found their way to North America on their own. Instead, they were introduced either purposefully or accidentally by people through a number of pathways.

    Our challenge is to interrupt the pathways of introduction. These pathways include: commercial shipping and barge traffic, researchers, aquaculture, public stocking, wild bait harvest, recreational boats and personal watercraft, live bait use by anglers, the nursery trade, aquascaping, aquarium releases, and the pet trade.

    Some exotic species in the Great Lakes that arrived through these pathways include purple loosestrife, zebra and quagga mussels, waterfleas, Eurasian ruffe, round goby, alewife; chinook, coho, pink and Atlantic salmon; and rainbow and brown trout. In fact, over the last two centuries, more than 139 exotic species have been introduced into the Great Lakes through these pathways.

    Of the 139 exotics, 77 are from Eurasia, 18 are from the Atlantic Ocean, 12 are from Asia, 7 are from the Mississippi River basin, another 7 are from the Pacific and southern U.S., and there were 18 whose origin could not be documented.

    How did these species get here? The largest portion of these was introduced by ships, followed by unintentional releases, multiple releases, unknown sources, deliberate releases, canals and diversions, and railroads and highways.

    What kinds of species have been introduced? Wetland plants rank first, followed by invertebrates, fish, algae, and fish pathogens. And, since this research was published, the Great Lakes have witnessed more introductions bringing the total number to over 160 species.

    This Far Side cartoon by Gary Larson helps emphasize a point about "biological pollution." It says: Well shucks! Ive lost again. Talk about your alien species luck! But, biological invaders are not just lucky. Often, they have attributes that give them a competitive advantage over our native species. They are usually aggressive and prolific species that mature quickly. They frequently leave behind diseases, parasites, predators, competitors, and other factors that keep the populations in their native ranges in check. Because theyre kept in check, these species usually are not a problem in their native habitat.

    In their new habitat, introduced species can be characterized as being good, bad, or ugly. Some species either have no impact or are considered to be beneficial. Those are the good. The bad species have a definite negative impact in their new habitat. And, ugly species are those that may have a significant negative impact in the future, but arent yet a definite problem.

    First, well start with the good those species that have been introduced and are beneficial in some ways. Pheasants are exotic species, but provide hunting or bird watching enjoyment. In the Great Lakes, most of the trout and salmon species are also introduced, but support charter and recreational fishing. Other exotics, like honeybees, provide benefits to agriculture.It is sometimes difficult to distinguish between a "good" and a "bad" exotic species because many exotics have both positive and negative effects. Without question, however, many are bad. We know that they have a definite negative impact.

    The poster child for bad aquatic exotic species is the zebra mussel. Zebra mussels and their cousins, quagga mussels, change the way we use our lakes and rivers. In many systems, they have had costly and devastating impacts.

    Zebra mussels are small, bivalve mollusks bivalve meaning that there are two halves to its shell. Theyre prolific creatures. A mature female can produce from 30 thousand to 1.6 million eggs per year. During spawning, the water can be so thick with zebra mussel larvae, called veligers, that there could be more than 100 in a coffee cup scoop of water. These veligers are about the diameter of a human hair, and drift on water currents.

    Two to four weeks after hatching, the free-swimming larvae settle and attach to any solid object, including each other. If they attach to movable objects, such as a boat, they can be spread to other waterways.

    Zebra mussels attach to surfaces by secreting sticky fibers, called byssal threads. A single, tiny zebra mussel poses no threat..

    but they are rarely found as scattered individuals.Given the right conditions, they can appear by the billions and form thick carpets that can cover lake and river bottoms.

    The impacts of zebra mussels are varied. One type of impact results from their feeding. Adults feed by drawing water into their bodies, and then filtering and consuming the suspended particles that are in that water. Each adult mussel filters about one liter of water per day. Based on zebra mussel densities in the western basin of Lake Erie, experts calculate that zebra mussels filter all of the water in the basin once every three days.

    Zebra mussel filtering may improve water clarity and make the water nicer to look at, but it alters plant and animal communities. For example, in lakes Erie and St. Clair, rooted aquatic plants have become established in areas where they have been absent for a long time. In other areas, aquatic plants have grown more densely than usual, and have extended into deeper waters because of increased light penetration. Aquatic plants now choke many marinas, boat basins, and harbors in the Great Lakes. Also, scientists believe that through their feeding, zebra mussels are disrupting the food web, leading to the...


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