Crustacean Research Vol.44: 75–92 ©Carcinological Society of Japan. doi: 10.18353/crustacea.44.0_75 The global trade in crayfish as pets Zen Faulkes Abstract.̶The sale of crayfish in the pet trade has increased in recent decades, and a substantial fraction of the world’s entire range of crayfish species is available in the pet trade. The market for pet crayfish creates two major concerns: the potential for over exploitation of natural populations of crayfish to supply the pet trade, and the negative consequences resulting from the release of non-indigenous crayfish into nat- ural habitats. The chain from the source of crayfish to the final owner can be lengthy, and each step in the supply chain needs to be studied by different methods. While there are often regulations intended to limit the trade of crayfish as pets, they differ widely from place to place and seem to have limited success in changing the behav- iour of owners of pet crayfish. Key words: aquarium, ornamental animals, methodology, new species, policy, risk assessment ■ Introduction buy freshwater organisms than marine ones (Chapman et al., 1997). Thus, crayfish have a Pet keeping is tremendously popular, but the potentially greater distribution among pet own- trade in pets is largely a “grey market”. It is ers than marine crustaceans. Second, there has difficult to find information on species avail- been a pronounced increase in the keeping of ability, the amount of trade, and the source of crayfish as pets, particularly in Europe, since pets (Calado et al., 2003; Rhyne et al., 2012, the 1990s (Patoka et al., 2015c; Chucholl, 2015). 2016). Third, the release of crayfish, often un- In the United States, 10% of people are esti- intentional, has already had very clear ecologi- mated to have aquaria (Chapman et al., 1997), cal and economic effects, and they are usually which can house many different kinds of or- bad ones (Gherardi et al., 2011; Twardochleb ganisms. Fish are probably both the most popu- et al., 2013). These negative effects include the lar organisms kept in aquaria, and the most introduction of diseases, such as crayfish popular subjects for research on the pet trade. plague (Mrugała et al., 2015), and direct com- The trade in aquatic plants and invertebrates petition with indigenous species (Lodge et al., for aquarium use has been less well studied 2000). To date, crayfish-caused problems are (but see Kay & Hoyle, 2001 on aquatic plants). more severe than yet seen for other decapod There has been a tendency to describe inverte- crustaceans sold as pets, such as freshwater brates as “incidental” contaminant species in crabs (Ng et al., 2015) or shrimps (Klotz et al., the pet trade, hitchhiking on larger organisms 2013). (Keller & Lodge, 2009; Duggan, 2010). Many In this paper, I describe the trade in crayfish different kinds of aquatic crustaceans are sold as pets, discuss the reasons and methods used as pets (Calado et al., 2003; Klotz et al., 2013; to study the pet trade, and the regulation and Ng et al., 2015), but this review focuses on policy issues around the trade. crayfish for these reasons. First, more people Received: 15 Aug 2015; Accepted: 4 Oct 2015; Published online: 17 November 2015 75 ZEN FAULKES ■ Many crayfish species are sold as pets da-Veiga et al., 2014), and there is no reason to expect the same would not hold true for cray- The trade in crayfish has been systematically fish. Cherax peknyi has a striking natural co- examined in eight countries, with partial re- lour pattern (Lukhaup & Herbert, 2008). Cam- ports in others. There are about 600 known barellus patzcuarensis and Procambarus alleni crayfish species in the world (Crandall & Bu- sold in the pet trade are available in bright co- hay, 2008; Richman et al., 2015), and about loured morphs that are dramatically different 130 crayfish species have been reported as than their normal, relatively drab, wild type co- available for sale as pets (Tables 1 and 2). Most louration. The orange morph of Cambarellus of these species originate from North America patzcuarensis appears to be traceable back to a and Australasia (Chucholl, 2013b; Faulkes, single hobbyist in the 1990s (Dost, 2013), and 2015b), which are the hotspots for crayfish bio- completely took over the pet niche for this spe- diversity (Crandall & Buhay, 2008; Richman et cies: the wild type colour, brown, is virtually al., 2015). never available. Procambarus alleni is often Thirty-eight crayfish species are available in available in a bright blue morph. Procambarus more than one country (Table 1), and the only fallax f. virginalis is marbled, and is partheno- species not from North America or Australasia genetic (Scholtz et al., 2003), which makes are Astacus leptodactylus and Astacus astacus. them easy to rear and gives them novelty value. Germany, the United States, and the United Both C. patzcuarensis and P. fallax f. virginalis Kingdom have crayfish species sold exclusive- are small species, which is also attractive to pet ly in those countries (Table 2), although differ- owners, since they can fit into smaller tanks, ences in species availability are probably likely more can be kept in larger tanks, and they are to get smaller over time, as more research on unlikely to attack or harm fish in the same tank the trade is conducted, and as more species are (Faulkes, 2013). distributed across borders. It is probably not The remaining three species̶Procambarus possible to give an exact number of species in clarkii, Cherax quadricarinatus, and Cherax any given market. Several species are sold destructor̶are also distributed for food- without a specific name or sold under incorrect related aquaculture (P. clarkii, Marshall et names. Indeed, one study found that pet stores al., 1988; C. quadricarinatus; Jones, 1995, never gave scientific names for animals sold, Garza de Yta 2016; C. destructor, Jerry et and pet stores were more likely to give incor- al., 2005), and perhaps only secondarily rect identification than other businesses, such used as pets (Kouba et al., 2014). Never- as bait sellers or biological supply companies theless, colour may play an important role (Keller & Lodge, 2009). To add to confusion, in their transition from plate to tank. Like sometimes the same common name is used for C. patzcuarensis and P. alleni, P. clarkii also multiple species. For example, both Cherax comes in a variety of brightly coloured gherardiae (Patoka et al. 2015a; Patoka et al., morphs, including blue, white, and several 2015c) and Cherax pulcher (Lukhaup, 2015) others, and buyers will pay more for blue were sold as “blue moon crayfish.” morphs (Faulkes, 2015b). The bright red patch- Seven crayfish species are sold as pets in es on the claws of male C. quadricarinatus more than five countries, roughly evenly split may also be a selling point for pet owners. between North American and Australian spe- cies. Four species are probably popular pets because of their attractive appearance. Hobby- ists strongly prefer brightly colored fish (Mace- 76 Crustacean Research 44 Crustacean Research 44 Crustacean Research 44 Crustacean Research Table 1. Crayfish species found in the pet trade of more than one country. Nations marked with an asterisk have not been surveyed comprehensively for species availability United Slovakia Turkey United States Brazil Ireland* Netherlands Germany Greece Czech Republic Singapore* Kingdom (Lipták & (Turkmen Species (Faulkes, (Loureiro (Faulkes, (Soes & (Chucholl, (Papavlasopoulou (Patoka et al., 2014a; (Belle et al., (Peay et al., Vitázková, & Karadal, 2015b) et al., 2015) 2015a) Koese, 2010) 2013b) et al., 2014) Patoka et al., 2015c) 2011) 2010) 2015) 2012) Astacus astacus Yes Yes Astacus leptodactylus Yes Yes Yes Yes Cambarellus diminutus Yes Yes Yes Yes Cambarellus montezumae Yes Yes Yes Cambarellus patzcuarensis Yes Yes Yes Yes Yes Yes Yes Cambarellus puer Yes Yes Cambarellus shufeldtii Yes Yes Yes Yes Cambarellus texanus Yes Yes Cambarellus zempoalensis Yes Yes Cambarus bartonii Yes Yes Cambarus diogenes Yes Yes Yes Cherax albertisii Yes Yes Yes Cherax boesemani Yes Yes Yes Cherax cainii Yes Yes Cherax destructor Yes Yes Yes Yes Yes Yes Yes Cherax gherardiae Yes Yes Cherax holthuisi Yes Yes Yes Yes Cherax lorentzi Yes Yes Yes Cherax monticola Yes Yes Cherax peknyi Yes Yes Yes Yes Yes Yes Cherax preissii Yes Yes Cherax quadricarinatus Yes Yes Yes Yes Yes Yes Yes Yes Cherax pulcher Yes Yes Cherax tenuimanus Yes Yes Crustacean Research 44 Crustacean Research Orconectes immunis Yes Yes Orconectes limosus Yes Yes Yes Yes Orconectes nana Yes Yes Orconectes neglectus Yes Yes Orconectes rusticus Yes Yes Orconectes virilis (cf. causeyi) Yes Yes Pacifastacus leniusculus Yes Yes Yes Procambarus acutus / zonangulus Yes Yes Procambarus alleni Yes Yes Yes Yes Yes Yes Yes Yes CRAYFISH PET Procambarus clarkii Yes Yes Yes Yes Yes Yes Yes Yes Yes Procambarus cubensis Yes Yes Procambarus fallax f. virginalis Yes Yes Yes Yes Yes Yes Yes Procambarus milleri Yes Yes Procambarus paeninsulanus Yes Yes Procambarus pictus Yes Yes 77 Procambarus vasquezae Yes Yes ZEN FAULKES Table 2. Crayfish species reported in the pet trade of only one country Germany (Chucholl, 2013b) Astacoides betsileonensis, Astacoides granulimanus, Astacoides cf. madagascariensis, Austropotamobius pallipes, Austropotamobius torrentium, Bouchardina robisoni, Cambarellus chapalanus, Cambarellus ninae, Cambarellus schmitti, Cambarellus sp. “ALA”, Cambarellus sp. “LOU”, Cambarellus sp. “HUB”, Cambarus asperimanus, Cambarus cf. chaugaensis, Cambarus conasaugaensis, Cambarus coosae, Cambarus coosawattae,