Enemy at the gates: introduction potential of non-indigenous freshwater crayfish in Greece via the aquarium trade

Abstract

Indigenous freshwater crayfish species (ICS) are important biodiversity components and desirable fishery targets. However, ICS populations are increasingly threatened by various anthropogenic stressors. Moreover, established populations of non-indigenous freshwater crayfish species (NICS) and new ‘waves’ of NICS introductions exert significant pressure on ICS populations at a pan-European level. These effects include direct competition for space and resources as well as crayfish ‘plague’ transmission from introduced North American species. Given low public knowledge of this problematic, considerable risk of future introductions exist as a result of conventional and internet-based aquarium trade, which often lead to deliberate and/or accidental releases of NICS into the wild. In 2011, we conducted a survey of freshwater crayfish species in eleven large-size pet shops located in three major cities and in three large internet-based aquarium companies in Greece. Overall, eight species belonging to three genera (Procambarus, Cherax and Cambarellus) were recorded, originating from the USA, Australia, New Guinea and Mexico. The invasion potential of the three most popular species was assessed using the Freshwater Invertebrate Invasiveness Scoring Kit (FI-ISK). Two species were determined to constitute a ‘very high risk’ of invasion. As such, regulatory measures need to be implemented to monitor the ornamental trade of NICS in Greece and a national framework developed for protecting ICS.

Ornamental fish in pet stores in Greece: a threat to biodiversity?

“…Western Europe, Japan, Australia, South Africa and particularly in the USA, with 1,802 marine ornamental species from 125 families entering the country on an annual basis; Davenport, 1996;Rhyne et al, 2012). Similarly, the number of freshwater crayfish species available to the aquarium stores in Greece was considerably lower, compared for instance to the German market (Papavlasopoulou et al, 2013). Species diversity observed in the aquarium sector of Greece may be attributed to various factors.…”

Imports of ornamental crayfish: the first decade from the Czech Republic’s perspective

“…Most probably, these originated from aquarium releases and include, for example, Procambarus fallax f. virginalis in Germany (Chucholl and Pfeiffer, 2010), Italy (Nonnis , the Netherlands (Soes and Koese, 2010), Slovakia (Janský and Mutkovič, 2010) and, surprisingly, Sweden (Bohman et al, 2013); Cherax destructor in Italy ; and Cherax quadricarinatus established in one location in Slovenia (Jaklic and Vrezec, 2011). While Procambarus clarkii is the most popular species for human consumption, it is probably equally important and popular in the aquarium trade and certainly highly invasive based on predictive evaluation in all studied countries (Italy, Germany, Greece, and Czech Republic) (Tricarico et al, 2010;Chucholl, 2013;Papavlasopoulou et al, 2014;Patoka et al, 2014a). Certain established populations of this species in the EU also originate from aquarium releases (Dehus et al, 1999;Chucholl, 2013).…”

Marmorkrebs (Procambarus fallaxf.virginalis) are the most popular crayfish in the North American pet trade

“…A few studies have begun characterizing the trade in crayfish in some countries. In Germany, 123 crayfish species were available for sale, of which 105 species were North American natives (Chucholl, 2013), compared to about 30 species recorded in the Czech Republic (Patoka et al, 2014a;Patoka et al, 2015), nine species in Turkey (Turkmen and Karadal, 2012), eight species in Greece (Papavlasopoulou et al, 2014), and one in Brazil (Loureiro et al, 2015). The pet trade in crayfish in North America has not been studied in depth, even though it is a large potential market for crayfish pets.…”