Observing & Collecting Crayfish. Collecting Crayfish. Crayfish in their Natural Habitat

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1 Observing & Collecting Crayfish Crayfish in their Natural Habitat Crayfish are found in many streams and lakes of the Pacific Northwest. This provides teachers the opportunity to observe crayfish in their natural environment, or collect their own teaching specimens. Crayfish use rocks, wood or clumps of vegetation to hide from predators, especially during the day when they are less active. Look for them in areas of a stream where the water flow is not too rapid. The largest ones will prefer to hide under larger structures, such as big rocks. Many things can motivate a teacher to prefer working with animals in their natural habitat. The educational merits of students learning outdoors are compelling. Student motivation and achievement soars, and observing animals in their own habitat enhances the opportunities for in-depth understanding. For some, ethical considerations drive the desire to humanely observe the animals in their natural habitat, particularly since all living specimens that are taken into a classroom setting must be disposed of and never returned to their environment. Collecting Crayfish Crayfish can be caught by hand by carefully grasping them behind their claws around the carapace (shell of the body). Of course, this process is likely to be much easier when they have been first captured in a net. D-frame nets or short seine nets can be held immediately downstream of likely crayfish habitat. Disturb the streambed by kicking or flipping over and rubbing the rocks, flushing everything downstream. The crayfish will be swept or tail-flip themselves backwards into the net. Lift the net quickly! Crayfish habitats dominated by aquatic plants or leaf litter are easily sampled by sweeping the net through the vegetation. Recently it was discovered that the import of non-native crayfish from other US regions for school studies has resulted in their invasion into local streams when released instead of disposed of properly. Observing in the stream habitat eliminates the need to import potentially nuisance species. Many schools do have suitable streams nearby, and not having to purchase crayfish saves money and the inconvenience of maintaining them in the classroom.

2 Resources Taking FOSS Outdoors Folio _ pdf Science in the Schoolyard Guide: FOSS Structures of Life Outdoors.pdf Crayfish Care and Handling Observing in the Field Dishtrays, buckets or other plastic containers make nice ourtdoor observation stations. Place a number of crayfish and some rocks or leaves in the container, and students can easily observe just as in the classrom. Other stream invertebrate bugs will likely also be present, providing lots of additional excitement. (See Resources for a key to benthic macroinvertebrates.) Multiple containers will allow students to observe in small groups and the opportunity to compare differences in behavior and habitat use. When finished, students can gently release all the collected materials back to the stream. Crayfish Invasion Video Brief Guide to Crayfish Identification in the Pacific Northwest h_id_guide.pdf Invasive Crayfish Information orities/crayfishfactsheet.pdf Washington State Invasive Species Council National Invasive Species Information Center Aquatic Invasive Species Curriculum Full Color Macroinvertebrate Identification Key Back to the Classroom or Not? Crayfish can be brought back to the classroom, assuming a proper habitat has been set up for them prior to collection. Transporting crayfish is fairly simple, as long as it is done promptly. They are resilient and do fine in a container of water or a box filled with wet moss. (They tend to puncture plastic bags.) Crayfish are quite adept at escaping, but be careful to not secure their container so well that they do not have air flow. Keeping them cool is critical. Crayfish brought into the classroom must not ever be released back into the environment, Complete care and disposal instuctions for crayfish are available at What to do if you find a non-native native invasive crayfish? Make it a teachable moment! The first thing to do is to call INFEST or report online at Your students can then contribute to the science community s efforts to understand the status of crayfish in northwest streams. Take detailed photographs of the crayfish, or preserve the specimen in alcohol, and contact: Julian D. Olden School of Aquatic and Fishery Sciences University of Washington Seattle WA e mail: olden@uw.edu

3 BriefGuidetoCrayfishIdentificationinthePacificNorthwest December2009 Signalcrayfish(Pacifasticusleniusculus) Washingtonhasonlyonenativecrayfishspecies,thesignalcrayfish.Itisfairlyeasily identifiedbyitsuniformbrownishorbluetingedcolorationasadultswithawhiteband atthejointoftheclaws(chelae).juvenilesofthesignalcrayfishwilllikelybedrabbrown withthewhitebandlessnoticeable.itisalsoquitesmoothonallitssurfacescompared toothercrayfish,especiallytheclaw. Redswampcrayfish(Procambarusclarkii) Theinvasiveredswampcrayfishwillberedasadultswithlonger,narrowerclawsthan thesignalcrayfish.additionally,redswampcrayfishclawswillbecoveredwithred, whiteorblackbumps(tubercules).redswampjuvenileswillbebrownbutwithabody shapeandpatternsimilartoadults,includingablack V patternonthedorsalsideof thetail(abdomen)andasaltandpepperpatternofspottinginblack,grey,whiteorred overthecarapace.

4 SIGNALCRAYFISH REDSWAMPCRAYFISH Northerncrayfish(Orconectesvirilis) Thenortherncrayfishisamediumtolargecrayfishandisdistinguishedfromsignaland redswampcrayfishbybroadflattenedtuberculate(i.e.,largetubercules)claws,anda olivebrownbodythatisdappledwithdarkbrown,andabdominalsegmentswithdark brownmedialspots.

5 Rustycrayfish(Orconectesrusticus) Theinvasiverustycrayfish,amajornuisancespeciesinthemidwestUnitedStatesand elsewhere,wasrecentlyfoundinthejohndayriveroforegon(oldenetal.2009).the speciesisnotyetknownfromothersitesinthepacificnorthwest.rustycrayfishmaybe bestidentifiedbytherustcoloredspotoneachsideofthecarapacenearthejointwith theabdomen(seefigures).rustycrayfishalsofrequentlyhaveblacktipstotheirclaws. RustycrayfishbelongtothesamegenusasOrconectesvirilis,buttheirclawsare generallysmoother althoughmaystillhavetubercules/bumpsincontrasttothenative signalcrayfish.

6 Crayfishthatdonotconformtothesedescriptionscouldbeotherspeciessuchasthe ringedcrayfishorconectesneglectusorthewhiterivercrayfishprocambarusacutus. PLEASEPHOTOGRAPHANYCRAYFISHTHATYOUARENOTABLETOIDENTIFY. PLEASEKEEPVOUCHERSPECIMENSOFANYNONNATIVECRAYFISH(depositinethanol). GettingYourSpecimenstotheUniversityofWashington Onceyouhavecollectedsomenonnativespecimens,I dliketomakearrangementsto getthemtouw.pleasegivemeacall: JulianD.Olden,Ph.D. AssistantProfessor SchoolofAquaticandFisherySciences UniversityofWashington Box355020;SeattleWA98195 phone: web: skype:goldenolden