The Known Cravfishes of Arizona: A Summarv Renort Prepared By Terry Inman Bio.310 For Dr. Paul C. Marsh ASU Center for Environmental Studies Introduction The crayfishes ofNorth America display greater diversity in terms of species than any other part ofthe world. Some 338 recognizedtaxa (308 species and 30 subspecies) exist within the United States and Canada (Taylor, C.A. et d,. 1996). At least one species of crayfish is native to every state in the contiguous United States (Hobbs, H.H. Jr. l9S9) except Arizona which claims no species of its own. Until recently Arizona had (from our earliest records) remained void ofthis diverse group of invertebrates. However, sometime within the last 30 years crayfishes have begun to show up in Arizona waters. Some have been intentionally stocked by the Arizona Game and Fish department (AZGFD stocking records l93l - l99l) and the U.S. Fish and Wildlife Service (verbal - MarstU P.C.) as forage for game fish such as trout and large mouth bass. Although the extent ofthe introductions by the USFWS in not known, the AZGFD has reported three sites of introduction (all lakes), one inl97l, and two in 1991. other sources of crayfish introduction have probably been a result of bait bucket introductions by sport fishermen. Although no direct evidence ofthis is known it is perhaps the most reasonable explanation for their wide spread existence. Despite crayfishes having become common fauna in many Arizona waters they have managed to attract little attention from any Federal, Statg or scientific community. The kinds, distribution, and abundance of Arizona's crayfish is unknown, they have not yet been inventoried, or studied. Dr. Paul Marsh from Arizona State University's Center for Environmental Studies was among the first to recognize the need for an in depth look at crayfish in Arizona. Under the direction of Dr. Marsh it has been the scope of my study to acquire crayfishes from around Arizona (by collection and receiving from other sources), to note where they were obtained from, to identify each individual to species if possible, to catalog each collection, and prepare a distribution map and a sunmary report of my findings. Collection Crayfish may be collected by a variety of methods such as seining (using aYq inch mesh), minnow traps baited with meat, dip netting, and electrofishing, all of these methods have proven effective. While dip netting, electrofishing and seining are all active methods of capture, baited minnow traps are not, and may require an overnight stay in order to yield the best results. The type of bait used may also play a significant role in the success of collection efforts. My experience and the findings ofKutk4 F.J. et aL. (1992) suggests that fish pieces are a highly attractive bait to crayfish, and oily fish (such as smelt, or anchovies) are most often preferred to non oily fish (such as cod and pollock). Crayfish are best preserved by placing them in a solution of 6 percent neutral formalin forlZ hours or up to one week depending on the size (Flobbs, H.H. Jr. 1972). After being rinsed in running water for a few hours, specimens should then be transferred to a70 percent ethyl alcohol solution, o4 a20 to 30 percent isopropyl alcohol may also be used (flobbs, H.H. Jr. 1972). Identification In order to accurately identify crayfish to species it is necessary to have a'form f' male. From I males (or sometimes referred to as "lo form") occur in the subfamilies Cambarinae and Cambarellinae. Males in both subfamilies undergo cyclic dimorphism that is associated their reproductive cycle. Crayfishes of more northern climates follow a circular rhytfun, that is to say that at the end of their first season breeding males molt and are returned to a juvenile morphology (known as'form If" or'2d form') until the next breeding season when the semiannual molt returns them to form I breeding males. This cyclic regression takes place throughout the life span of breeding males. It is typical in Northern populations to find all adult males in either the form I or form II state. However in species occurring at lower latitudes there is no well defined breeding season, therefore, form I and form II males may occur in many populations at the same time (Hobbs, H.H. Jr. 1972). Form I males maybe distinguished from form II and juvenile males by the occulrence of"corneus, or horney, terminal elements (projections) on the distal ends of the first pleopods" (rlobbs, H.H. Jr. 1972) (see appendix a, fig 2 for pleopods). It is important to note that the size ofthe crayfish will not determine whether it is in form I or form II. Molting increases the size of the crayfish and molting rnay also regress the individual to a form II state, because of this, a form tr male may be larger than a form I male. Most identification keys are based on form I males since their pleopod morphology is much more distinct from the pleopods of form fI males and the juveniles of other closely related species. In North America the usage of from I males for identification applies to all crayfishes except for those belonging to the genus Pacifastacus which do not exhibit cyclic dimorphism. The following appendices relate to the anatomy, identification and catalog specimens ofArizona's crayfish species: appendices d B, and C. Arizona's known crayfish species I have separated Arizona's known crayfish species into two categories; the first category is the crayfishes that are known to occur in wild populations, and the second category is the crayfishes that are known to occur in pet stores and therefore private aquariums. It is important to mention that the collection efforts are still on going and that not every region ofthe State has been surveyed or exhausted in collection efforts, hence the usage of the words "known crayfishes". The wild crayfishes that have been collected thus far are Procambarus ctarkii whose cofilmon name is the'?ed swamp crayfish" and Orconectes virilis whose common name is the'horthern crayfish". Proccnnbarus clarkii has a native range from north- eastern Mexico and south-central USA west to Texas and east to Alabama, north to Tennessee and Illinois (floldich and Lowery l9s8). It is among the most widely distributed of all crayfish species in the United States and has been successfully introduced into fourteen countries worldwide (Holdich and Lowery 1988). Despite the apparent popularity af Procarnbarus clarkii as a food source in the southern United States, it is considered a pest in some countries (as well as some areas in the United States) such as Japan where it is blamed for the destruction of Rice seedlings, taro roots, and fishing nets. The often intense burrowing activity by large populations of Pracanbarus ctarkii has also been known to cause extensive damage to earthen dikes and other water control structures (floldich and Lowery l98s). The habitat preferences of P-. clsrkii include lentic and lotic habitats, with fine silt to gravel substrates. They are also known to burrow (see appendix D for an Arizona distribution map). Orconectes virilis is the most widely distributed Canadian species of crayfish with a native range that spans from Saskatchewan to Ontario, eastward to Maine, and from Montana to Utah and east to Arkansas. Orconectes virilis has been introduced into several states from the east coast to the west coast. While it has not achieved the popularity of^P. clarkii as a human food source (most likely due to its smaller size), it has achieved popularity as a'bait fish", this may in part explain its substantially expanded range. The habitat preferences of Orconectes virilis ranges from lentic to lotic waters with substrates that range from silt to cobble (see appendix D for an Arizona distribution map). The pet shop varieties ofcrayfishes that I have collected thus far have been Procambarus alleni and one advertised tobe Procambarus paeninsulanus. The Procambarus alleni specimen came from Pets Inc. a small pet store on the north-west corner of Nfill and Southern in Tempe. Pets inc. sells them as forage for oscars and other large aquarium fishes. Upon inspection ofthe aquarium small white translucent egg shaped sacks could be seen on the thorax of each crayfish, some with many (ca. 20 -30) and others with just a few (5-6). The specimen that I procured only had a few of these egg like sacks, and upon preservation ruptured. No identification ofthe sacks has yet been made. The stores owner is aware of the sacks, but does not know what they are, just that'they come this way''. No name was given on the tank and the owner nor his employees knew the genus, species or common name of the crayfish they carry. Procambarus alleni is not a widely distributed crayfish species, their entire range is within the State ofFlorida where their numbers are currently stable. They occur in both lentic and lotic environments and prefer to burrow. Petco at the south-east corner ofMcClintock and Warner Roads in Tempe advertise their crayfishas Procambwus Weninsulanus (which were also being sold as forage and as a unique addition to freshwater aquariums), however, upon identification it turned out to be Procambarus clarkii. This miss representation carries many implications, for example it may mean that the pet store doesn't know the species it receives, and perhaps the distributor doesn't know what species it is distributing. However, it should not be assumed that Procambarus paeninffilarrus has never been canied or that it won't be carried at that pet store in the fufure. Procambarus paeninsulamts has a native range of Alabama, Florid4 and Georgia and has not been introduced elsewhere.