Towards a sustainable human use of freshwater crayfish (Crustacea, Decapoda, Astacidea)

Abstract

Key-words: direct and indirect uses, surrogate species, option values, existence and bequest values, Crustacea Decapoda AstacideaTo face the severe loss in biodiversity recorded in freshwater crayfish (Crustacea, Decapoda, Astacidea), there is an increasing awareness that the CBD's concept of the sustainable use of natural resources should be applied also to this large assemblage of species. This review paper will synthesize the several uses we make or have made of crayfish with the purpose of pinpointing where sustainability is desirable and feasible. Uses are here classified as direct (i.e. consumption and production) and indirect. The latter uses refer to the recreational, cultural, ethical, aesthetic, scientific and education values of crayfish. An additional indirect use regards the environmental key role this taxon plays. Several examples, mostly related to Europe, will be provided to illustrate the importance of crayfish to human societies, culture and history. The potential of assigning a non-use value to them will be finally discussed. Pour faire face à la perte de biodiversité enregistrée pour les écrevisses d'eau douce (Crustacea, Decapoda, Astacidea), il y a une prise de conscience accrue que le concept de bioconservation (CBD) pour l'emploi durable des ressources naturelles devrait s'appliquer à ce large assemblage d'espèces. Cette revue veut synthétiser les nombreux usages que nous faisons ou avons faits des écrevisses avec le but de mettre le doigt sur les cas où la durabilité est souhaitable et faisable. Les usages sont classés ici en directs (i.e. consommation et élevage) et indirects. Ces derniers usages concernent la valeur récréative, culturelle, éthique, esthétique, scientifique et éducative des écrevisses. Un usage supplémentaire indirect concerne le rôle environnemental clé que ce taxon joue. Plusieurs exemples, la plupart pris en Europe, sont cités pour illustrer l'importance des écrevisses pour les sociétés humaines, leur culture et leur histoire. La possibilité de leur attribuer une valeur de non-usage est finalement discutée. RÉSUMÉ

Growth performance of Noble Crayfish Astacus astacus in recirculating aquaculture systems

“…data). All water parameters in the RAS were able to be held in accordance to the crayfish needs and the requirements of RAS (EIFAC 1998) and were held constantly on this level during the experiment (Hager 2003;Jeske 2010;Sander 1998;Wickins and Lee 2002;Füreder 2009). Therefore, crayfish mortality and growth should not have been affected by these conditions.…”

“…After the introduction of the American crayfish species, Pacifastacus leniusculus and Orconectes limosus, in the late nineteenth century and concomitant highly infectious crayfish plague (Aphanomyces astaci), vast populations perished and A. astacus numbers in Europe decreased drastically (Edgerton et al 2002;Westman and Savolainen 2001;Holdich et al 2009;Holdich 2002). Other factors like water pollution and habitat alteration and destruction have led to the species now being considered endangered (Edsman et al 2010; Gherardi 2011) with only small and isolated wild populations remaining (Füreder 2009). Limited availability has increased the economic value of this once common consumer good to a luxury food product available in small quantities only on local markets for currently 35-50€/kg live weight (Taugbøl and Skurdal 1988;Franke et al 2011).…”

“…By excluding the risk of infection and offering stable and controlled growing conditions, recirculating aquaculture systems (RAS) may offer a lower-risk and a more stable and economically viable system for A. astacus production for the food market or for restocking programs, compared to open-pond systems (OPS). Currently, crayfish are cultured in OPS (Ackefors 2000;Cukerzis 1988), where the economic risk of a crayfish plague infection is high and the growth period is limited to a maximum of 6 months per year (Füreder 2009;Taugbøl and Skurdal 1988). In addition, the intensive work load and the mortality rates of up to 90 % due to predation and cannibalism are limiting factors for large farms (Hager 2003;Dethlefs 2007;Daws et al 2002;Usio et al 2001).…”

“…The state-of-the-art method for culturing A. astacus and other crayfish species remain OPS (Ackefors 2000;Ó Sullivan et al 2012;Wickins and Lee 2002;Huner 1994), where sufficient space is available to reduce cannibalism, and food is, at a minimum, partially supplied by the pond itself. These systems are exposed to local environmental conditions (i.e., temperature, feed), and production levels are extremely low (Füreder 2009). …”

Socio-economic drivers and non-indigenous freshwater crayfish species in Europe

“…the description of metabolic rifts created in Mediterranean bluefin tuna fishery in Sicily; Longo, 2010). Freshwater crayfish have an over time importance to local European societies both as utilitarian (food) and cultural/traditional items since the ancient times (Swahn, 2004;Koutrakis et al, 2009;Gherardi, 2011). The populations of the five European indigenous crayfish species (ICS) [noble crayfish (Astacus astacus (Linnaeus, 1758), narrow-clawed crayfish Astacus leptodactylus Eschscholtz, 1823, thick-clawed crayfish Astacus pachypus Rathke, 1837, stone crayfish Austropotamobius torrentium (Schrank, 1803) and white-clawed crayfish Austropotamobius pallipes (Lereboullet, 1858)] once abundant, were seriously devastated by the 'crayfish plague' which was brought by asymptomatic crayfish species initially imported from North America during the late 19th century (Alderman, 1996;Diéguez-Uribeondo, 2006).…”