IF YOU FIND MUDSNAILS If you suspect you have found mudsnails, collect 5 to 10 New Zealand Mudsnails individuals and place them in a plastic bag into which you have sprinkled water. Check against the simple traits above and on this Web page to confirm identification: http://www.esg.montana.edu/aim/mollusca/nzms

Please save the samples and contact the Oregon Invasive Species Council (1-866-INVADER or online at oregoninvasiveshotline.org) and one of these specialists:

Sam Chan and Tania Siemens How to Prevent Oregon State University Oregon Sea Grant Extension the Spread of New Zealand [email protected] Mudsnails through Field Gear Robyn Draheim Center for Lakes and Reservoirs Portland State University [email protected]

Paul Heimowitz U.S. Fish and Wildlife Service [email protected] This brochure is a guide for field detection and for Cynthia Tait USDA Forest Service treating field gear to [email protected] prevent the spread of New Sherri L. Johnson Zealand mudsnails. PNW Research Station It is intended for researchers, USDA Forest Service [email protected] monitoring crews,

watershed survey groups, Design by Stefania M. Padalino. M. Stefania by Design Cover photos: top three photos by D. L. Gustafson; bottom two photos by Jane and Michael Liu. Liu. Michael and Jane by photos two bottom Gustafson; L. D. by photos three top photos: Cover ORESU-G-10-001 and anyone else who travels To order copies of this brochure, call 541-737-4849 or e-mail Oregon Sea Grant, frequently between aquatic [email protected]. You can also download a pdf at http://seagrant.oregonstate.edu/sgpubs/onlinepubs.html or riparian locations.

EGON O •OR •ALA AH SK ID A C STATES MAR CIFI INE PA

F IS N HER SIO W IE IS A S COMM A S NI HIN OR GTON • CALIF Second Edition Copyright 2010 by Oregon State University | Published by Oregon Sea Grant February 2010 IDENTIFYING THE NEW ZEALAND MUDSNAIL

Size: A mature snail is usually less

inches than 5 mm (.2 in) long. (Photo by Jane and Michael Liu.)

1DevilsDevills Lake, Lake, Oregon, Oregon is is heavily heavily infested infested with with New New Zealand Zealand mudsnails.mudsnails. Prevent Prevent the the spread spread of of New New Zealand Zealand mudsnails mudsnails by bycleaning cleaning Shape: Shell is elongated and dex- geargear and and boats boats and and not not moving moving water water fromfrom infested waters waters into into new new bodies bodies of of water. water. (Photo by Jane and Michael Liu.) tral (its whorls or spirals lean toward the right). Snail typically has INTRODUCTION Range Range expansion expansion of of the the mudsnail mudsnail between 5 to 6 whorls on its shell. hashas been been unwittingly unwittingly hastened hastened by (Photo by D. L. Gustafson, http://www.esg.montana.edu/aim/ The New Zealand mudsnail mollusca/nzms.) (Potamopyrgus antipodarum) is an anglers,by anglers, hunters, hunters, and and field field person person- - introduced aquatic species that has nel—innel—in other other words, words, people people whowho 1 whorl invaded estuaries,estuaries, lakes,lakes, rivers, rivers, and frequentlyfrequently move move from between one watershed streams streamsand streams in Washington, in Washington, Oregon, Oregon, toand the lakes next, inhauling watersheds, wet waders, hauling nets, California, and many other states andwet other waders, gear nets, with and them. other Once gear withthe mudsnailthem. Once is established the mudsnail in ais new estab- in the western U.S. ItIt waswas firstfirst notednoted Color: Most snails have a light- to habitat,lished in it ais new impossible habitat, to it iseradicate impossi - in North America in the late 19801980ss inin dark-brown shell that may appear itble without to eradicate damaging it without other damaging com- the Snake River and has since spread to be black when wet. (Photo by Jane and throughout the West. ponentsother components of the ecosystem. of the eco- Thus, Michael Liu.) TheThe smallsmall sizesize, (< cryptic 5 mm), coloration, cryptic preventingsystem. Thus, unintentional inspecting, spreadremoving, by coloration,and ability toand survive ability out to surviveof water out inspecting,and treating removing, gear before and moving treating to offor water weeks for make weeks the make New the Zealand New Zea - geara new before water moving body to is athe new most water Embryos: Upon dissection, mature landmudsnail mudsnail an ideal an ideal hitchhiker. hitchhiker. bodyeffective is the means most effective of preventing means the ofspread minimizing of mudsnails. the ecological harm snails will have brooded embryos. (Photo by D. L. Gustafson, http://www.esg.montana.edu/aim/ posed by mudsnails. mollusca/nzms.)

Operculum: The mudsnail operculum (a rounded plate that seals the mouth of the shell when the animal’s body Snails2 Snails can canbe inadvertently be inadvertently transported transported in bootlaces (center— is inside) can be seen on live snails notein different bootlaces color). (center-note (Photo bydifferent Jane and color). Michael Liu.) but is not easily visible on dead or 3TheThe New New Zealand Zealand mudsnail mudsnail is often less less than than 5 5mm mm long. long. (Photo by Jane and Michael Liu.) preserved snails. (Photo by D. L. Gustafson, http:// www.esg.montana.edu/aim/mollusca/nzms.)

New Zealand Mudsnail Prevention Guide 2 chloride [DDAC]). Formula 409® The biology, ecology, and distribu- Cleaner Degreaser Disinfectant THE MUDSNAIL PROBLEM tion rate of the mudsnail suggest has been proven effective for The New Zealand mudsnail is a that many habitats are suitable for killing mudsnails at 50% dilu- threat to our waters. By competing further expansion. tion. with native invertebrates for food Mudsnail populations in the West and habitat, it has a detrimental The compounds Quat 128® and are self-reproducing brooders; they impact on fish populations, vegeta- Sparquat 256® are commercial dis- This test chamber contains a New Zealand mudsnail with clone themselves and retain the chemical test solution. (Photo by Robert Hosea.) tion, and other native biota. infectants with an active ingredient embryos inside their shell until they Mudsnails can tolerate a wide (QAC) similar to that of Formula 409® are large enough to release. Also CAUTION range of habitats, including brack- Cleaner Degreaser Disinfectant, known as parthenogenesis, this re- ish water, and are found living in which has proven effective for killing Treating field gear with chemical productive technique means that a high densities (often over 400,000 mudsnails and other aquatic inva- methods may result in unintended single mudsnail can rapidly colonize snails/sq meter) on many different sive species (see the table on the contamination of the environment. a new location. substrates (rock, gravel, sand, mud, foldout page for dilution rates). In particular, extreme caution must Mudsnails are easily transported vegetation, and even the shells of be taken to avoid contamination to new habitats by recreationists Many household bath and kitch- other organisms). en disinfectants contain quaternary of waterways and wetlands. DO NOT and field crews because the snails ammonium compounds (check the rinse your treated gear in a water body. readily attach to or are wedged label for active ingredients contain- Treating rubber gear or boots into the many cracks, crevices, and ing alkyl dimethyl benzylammonium with Formula 409® and other dis- crannies presented by waders, boot chloride [ADBAC]; diecyl dimethyl infectants with QACs may result in soles, nets, and buckets. New Zea- ammonium chloride [DDAC]). surface cracking of the rubber and land mudsnails can live for weeks loss of water repellency. Chemical in damp, cool conditions; can easily These and other chemical treat- methods are not always effective in survive on field gear for long periods ments are constantly being evalu- killing mudsnails. Always scrub your Mudsnails can attach to the seam of a stream boot. of time; and can be transferred to a ated and are updated online at Unintentional transport from one stream location to an- gear and consider using physical other by hitchhiking on waders or wading boots is one of new environment when that gear is seagrant.oregonstate.edu/themes/ methods before resorting to chemi- the primary vectors for spreading New Zealand mudsnails. (Photo by Jane and Michael Liu.) reused. invasives/ cal methods. For more information on the testing of chemical treat- ment methodology, see R. C. Hosea, and B. Finlayson, 2005, Controlling the Spread of New Zealand Mud Snails on Wading Gear, Administra- tive Report 2005-02, Rancho Cor- dova, California: Resources Agency, California Department of Fish and 1995 2001 2009 Game. Fishing docks and boats are potential conduits for spreading These maps show the spread of the New Zealand mudsnail from 1995 to 2009 in the western U.S. New Zealand mud- the New Zealand mudsnail. (Photo by Jane and Michael Liu.) snails have recently been found in parts of the Great Lakes region. (Maps courtesy of Amy Benson, U.S. Geological Survey.)

New Zealand Mudsnail Prevention Guide 6 3 PHYSICAL These methods for cleaning gear are effective as well as environmentally sound. Use one of the following methods: Freeze your gear for a minimum of 4 hours to kill all mudsnails. Freezer Mudsnails can pass through the intestinal tract of a fish. Almost half the mudsnails survived this temperatures should be at 26°F (-3°C) or below. trip. (Photo by M. Vinson, http://www.esg.montana. edu/aim/mollusca/nzms.) Soak gear in a bath of hot water (at least 120°F, 46°C) for 10 minutes. This method is not advised for Gortex. Dry your gear before reuse. A drying time of at least 48 hours under low humidity is recommended to remove all pockets of dampness. PREVENTION Gear must be completely dry for a minimum of 24 hours. Check to To prevent the survival of mudsnails on field clothing and equipment, ensure that boots are totally dry. you will need first to clean your field gear and then to treat it, using either the physical or chemical methods listed below. We recommend the CHEMICAL following steps: Common disinfecting cleaners containing quaternary ammonium com- 1 If possible, keep several changes of field gear for use in different pounds (e.g., alkyl dimethyl benzylammonium chloride [ADBAC]; diecyl bodies of water. dimethyl ammonium chloride [DDAC]) are effective for decontaminating gear. Disinfectants listed below will kill other aquatic invasive species but 2 Clean all gear before leaving a site, scrubbing with a stiff-bristled may not result in 100% mortality (see table on foldout page). scrub brush and rinsing with water, preferably high-pressure. This is Gear should be soaked in one of the following solutions for 5 minutes often the simplest and most effective for prevention. and then rinsed thoroughly with tap water, away from the water body. 3 Inspect gear before it is packed for transport. Visible traces of sand, Store and dispose of solution and used rinse water properly. mud, gravel, and plant fragments are signs that gear has not been Commercial disinfectant solutions containing quaternary ammonium properly cleaned and mudsnails may have been retained. compounds (QAC) (e.g., Formula 409® Cleaner Degreaser Disinfectant, alkyl 4 Select a treatment method in addition to scrubbing and rinsing if dimethyl benzylammonium chloride [ADBAC]; diecyl dimethyl ammonium mudsnails are present or suspected to be present.

Freezing, hot water, or drying treatments are recommended over chemical treatments because they are usually less expensive, more envi- ronmentally sound, and possibly less destructive to gear. However, most physical methods require longer treatment times and often cannot be performed in the field.

Chemical treatments require a 10-minute soak in a special solution The toe of this rubber wader boot has cracked after being (see “CHEMICAL,” page 5). After chemical treatment, gear must be exposed to repeated applications of benzethonium chloride. (Photo by Robert Hosea.) rinsed thoroughly with tap water away from all bodies of water, and all soak solutions and rinse water must be properly disposed of. A worker filters the cleaning solution after removing wading gear. (Photo by Robert Hosea.)

New Zealand Mudsnail Prevention Guide 4 5 to missanew infestation! could invasive. youany be species suspect gica bose shape, larger bottom whorl, andawhite tip(seeFigure 2). freshwater environments. Zealand, occurs to in brackish land mudsnail, native to New waters, whiletheNew Zea in highersalineto brackish pan, occurs more frequently parisitologica Oregon, in2007. first discovered in Bay,Coos human lungfluke parasite, intermediate host to the parisitologica invasive snail, with anothernonnative mudsnail habitat overlaps estuaries,In New Zealand Juga silicula can bedistinguishedby itsgrooved whorls;however, otherspeciesofJugasuchas 2.5 cm;New Zealand mudsnailsare nolarger than6mm). When small, as New Zealand mudsnailswhenjuveniles, butthey grow to bemuchlarger (upto land mudsnails, butthey lackanoperculum. “Rock” snails( small,also bevery like New Zea ing “pond” snails( whorls).Air-breathmore-uniform mudsnail, whichtends to have (as compared to theNew Zealand ally larger thanitsupperwhorls bottom whorlthat isproportion cal New Zealand mudsnail)anda shell(vs. theconiglobose-shaped distinguished by itsmore-rounded, “Pebblesnails” ( gus antipodarum Zealand mudsnails( commonly misidentified asNew tive to thePacific northwest are Several freshwater snailsna LOOK-ALIKES MUDSNAIL is also a high-alert invasive isalsoahigh-alert species that shouldbereported. canhave smoothwhorlssimilarto theNew Zealand mudsnail. , native to Ja , whichisan Assiminea Assiminea Fluminicola ) (seeFigure 1). Assiminea Assiminea Lymnaeidae Potamopyr - - Assiminea parisitologicaAssiminea ) canbe - ) can - might be foundmight be together inbrackish-water estuaries. with Figure 2. - - - - Assiminea parsitologicaAssiminea rock snails (Family Lymnaeidae) Northwest. From to right: left New Zealand mudsnail, snail apond gus antipodarum) Figure 1 New Zealand New Comparison oftheNew Zealand mud snail(three snailsonright) mudsnail It isbetter to It have than report asuspected . Comparison oftheNew Zealand mudsnail (Juga plicifera) (Juga

canbedistinguishedby itsglo withthree freshwater snailsnative to thePacific (three invasive Both snailsonleft). snails , two pebblesnails pebblesnails , two . Juga sp. Assiminea parisitol Assiminea Remember: report report Remember: (Fluminicola sp.) ) canbeassmall Juga plicifera (Potamopyr , and two , andtwo - - -

Aquatic Invasive Species of Concern, and Current Methods for Disinfection of Gear and Equipment (Adapted from USDA Forest Service Region 4 Guidelines for disinfecting fire equipment, summarized by Cynthia Tait: http://www.fs.fed.us/r4/resources/aquatic/guidelines/aq_invasives_interim_fire_guidance08_final.pdf) NOTE: A more complete—and continuously updated—table is available online at seagrant.oregonstate.edu/themes/invasives/

Decontam. Method Whirling Disease New Zealand Mudsnails Chytrid Fungus Zebra/Quagga Mussels Didymo Eurasian Watermilfoil

o o o o ≥ 60 C (140 F) water for 46 C (120 F); minimum of o o Hot water or 90 oC (195 oF); 10 minutes 5 minutes 60 C (140 F); minimum of minimum of 1 minute 60oC (140oF); 1 minute No data, but likely freezing o o 5 minutes Freezing may be effective, but effective -3 C (27 F); > 4 hours not tested Be dry for 24 hours, in sunlight Be dry for 48 hours, in sunlight Be dry for 3 hours, in sunlight Be dry for 48 hours, in No data, but likely Drying best best best 3–5 days, in sunlight best sunlight best effective For 10 minutes: For 1 minute: 1% bleach solution For 10 minutes: Gear rinsed with 0.5% bleach 2% bleach solution Bleach (e.g., Clorox® (500 ppm NaClO) 7% bleach solution (0.4% solution (250 ppm NaClO) (800 ppm NaClO) or equivalent bleach • 1.1 liquid oz bleach per gallon Not effective at the necessary NaClO) (>3,500 ppm NaClO) • 0.6 liquid oz bleach per gallon • 1.8 liquid oz bleach product) 6% sodium water concentrations without • 9 liquid oz bleach per gallon water per gallon water No data, but likely hypochlorite • 2.2 Tbsp liquid bleach per risk of damaging gear and water • 1.1 Tbsp liquid oz bleach per • 3.6 Tbsp liquid Clorox effective (NaClO) gallon water equipment • 7 gallons bleach per 100 gallon water per gallon water • 0.9 gallons each per 100 gallons water • 0.5 gallons bleach per 100 • 1.4 gallons Clorox per gallons water gallons water 100 gallons water 10-minute exposure 4.6% Quat 128 (1,570 ppm QAC Quaternary 15-minute exposure 4.4% active ingredient) ammonium Quat128® (1,500 ppm QAC • 6.4 liquid oz. Quat 128 per compounds (QAC) active ingredient) gallon of water 30-second exposure to (e.g., alkyl dimethyl • 6.1 liquid oz. Quat 128 per OR 0.015% Quat 128 No published data, but likely No published data, but benzylammonium gallon of water 3.1% Sparquat 256 (5 ppm QAC active effective likely effective No data chloride [ADBAC]; OR • 4.3 liquid oz. per gallon ingredient) diecyl dimethyl ® water • 1/8 tsp per gallon water ammonium chloride 3.1% Sparquat 256 OR [DDAC]) • 4.1 liquid oz. per gallon water Dilute 1 part Formula 409® Cleaner Degreaser Disinfectant to 1 part water