Kingdom | Phylum | Class | Order | Family |
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Animalia | Arthropoda | Malacostraca | Decapoda | Astacidae |
Scientific Name: | Astacus astacus (Linnaeus, 1758) | ||||||
Common Name(s):
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Synonym(s): |
Astacus astacus ssp. colchicus Kessler, 1876
Astacus fluviatilis Fabricius, 1775
Cancer astacus Linnaeus, 1758
Potamobius fluviatilis ssp. balcanicus S. Karaman, 1929
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Taxonomic Notes: | Astacus astacus is comprised of 3 sub-species: Astacus astacus astacus, Astacus astacus balcanicus, Astacus astacus colchicus. |
Red List Category & Criteria: | Vulnerable A2ad ver 3.1 |
Year Published: | 2010 |
Date Assessed: | 2010-06-08 |
Assessor(s): | Edsman, L., Füreder, L., Gherardi, F. & Souty-Grosset, C. |
Reviewer(s): | Collen, B. & Richman, N. |
Contributor(s): | Berg, S., Cammaerts, R., Fedotov, V.P., Hefti, D., Kozubikova, E., Machino, Y., Maguire, I., Manko, P., Miron, L., Pârvulescu, L., Puky, M., Pursiainen, M., Schulz, H., Sket, B., Śmietana, P., Zaikov, A., Soulsby, A.-M., Batchelor, A., Dyer, E., Whitton, F., Livingston, F., Milligan, H.T., Smith, J., Lutz, M.L., De Silva, R., McGuinness, S., Kasthala, G., Jopling, B., Sullivan, K. & Cryer, G. |
Justification: The Noble Crayfish (Astacus astacus) is a widespread species, it has undergone significant declines in population numbers due to non-indigenous species, crayfish plague, habitat loss and over-harvesting. Estimates of rate of decline in Sweden, Finland and Norway are as high as 78%, ~20% and 61% respectively over a 3 generation length period. Similar rates of decline are being seen within a number of other countries. Globally, this species is estimated to be declining at a rate of 50-70%, however in some parts of its range numbers are stable and there have been some successful re-stocking programs so the true rate of decline may in fact be slightly lower (40 - 50%) thereby qualifying this species for a listing under Vulnerable under criterion A2ad. |
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Previously published Red List assessments: |
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Range Description: | The Noble Crayfish, Astacus astacus, is indigenous and widespread throughout Europe. This species range extends from Russia and the Ukraine in the east, to Finland, Sweden, Norway in the north, to Greece in the south, and the United Kingdom and France in the west. A few recently introduced subpopulations are found outside Europe, for example Morocco. The occurrence of this species within Andorra, Cyprus, the UK, Liechtenstein, Luxembourg, Morocco and possibly Montenegro and Italy, is via introductions from neighbouring countries. | ||
Countries occurrence: | Native: Andorra; Austria; Belarus; Belgium; Bosnia and Herzegovina; Bulgaria; Croatia; Czech Republic; Denmark; Estonia; Finland; France; Georgia (Abkhaziya, Adzhariya, Gruziya); Germany; Greece; Hungary; Latvia; Lithuania; Macedonia, the former Yugoslav Republic of; Moldova; Netherlands; Poland; Romania; Russian Federation (Kaliningrad); Serbia; Slovakia; Slovenia; SwitzerlandIntroduced: Cyprus; Liechtenstein; Luxembourg; Morocco; Norway; Sweden; Ukraine; United KingdomPresent - origin uncertain: Italy; Montenegro | ||
Additional data: |
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Range Map: | Click here to open the map viewer and explore range. |
Habitat and Ecology: | This species is found in rivers, lakes, ponds, and reservoirs, in both lowlands and hills, where shelter availability is high (Souty-Grosset et al. 2006). This includes stones, logs, roots and aquatic and marginal vegetation. This species prefers soft bottoms with some sand and is not usually found in water bodies with a muddy substrate. In addition, it prefers soft banks where it constructs simple burrows. The oxygen demands of this species can be quite high, leading to high mortality in shallow, eutrophic ponds during summer months (Souty-Grosset et al. 2006). Habitat of this species is shared by the introduced Pacifastacus leniusculus, which is known to competitively exclude this species after a period of establishment (Souty-Grosset et al. 2006). This species is capable of tolerating lower calcium levels, as low as 2-3 mgl-1 Ca, where other species of crayfish may be excluded. The optimum temperature for best growth is between 16 and 24oC, although up to 28oC can generally be tolerated. In addition, oxygen content below 3-4 mgl-1 is deemed unsuitable for this species. This species is mainly predated upon by the common eel, in addition to small scale predation by mink, perch, otter and wading birds (Souty-Grosset et al. 2006), although predation risk also includes cannibalism. This competition, along with temperature gradients and shelter availability, is the major determinant of this species range (Abrahamsson 1966, Skurdal and Taugbol 2002). Anecdotal measures of longevity indicate this species may live for up to 20 years. At maturation, males normally mate every year, while female reproductive activity is usually restricted to a single year between periods of sexual inactivity. Thus numbers of sexually active females may vary greatly depending on locality and year (Souty-Grosset et al. 2006). Studies have shown (Jensen 1996) that this species of crayfish is particularly susceptible to increased levels of nitrite in aquatic systems, meaning input of excess amounts of this compound, particularly through agricultural fertilizer run-off, may pose a serious risk to this species.
It is known that noble crayfish females reach sexual maturity at a size which ranges from 6.2 cm total length in localities with early maturity or slow growth to 8.5 cm total length in localities with late maturity or fast growth. Males become mature at a size of 6.0-7.0 cm total length (Skurdal & Taugbøl 2002).
Declines in this keystone species are said to negatively impact both ecosystem structure and function within freshwater environments through loss of: a) provisioning services – food production from fisheries, recreational fishing, b) regulatory and support services – trophic cascades, water purification, nutrient cycling, primary productivity, c) cultural value – recreational fishing, education, heritage. Crayfish are also an important food source to a range of species including otters, salmonids, and birds such as kingfishers (Kettunen and ten Brink 2006). |
Systems: | Freshwater |
Generation Length (years): | 7.5 |
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Use and Trade: | Astacus astacus is commercially harvested as a food source in parts of its range. |
Major Threat(s): |
An outbreak of crayfish plague Aphanomyces astaci carried by the Signal Crayfish Pacifastacus leniusculus has had an impact upon all of Europe's Astacus species. Since the 1960s, the Signal Crayfish has been introduced into more than 20 countries in Europe (Kataria 2004, Füreder et al. 2006). The Signal Crayfish grows faster, reaches sexual maturity earlier, is more aggressive, and has the ability to dominate the use of many important factors like food and refugia (Füreder et al. 2006). The Signal Crayfish have also been shown to have a relatively higher population growth time than the Noble Crayfish. Even in watercourses where the Signal Crayfish is free from plague, it seems likely that the Signal Crayfish will out compete the Noble Crayfish, in the long term (Kataria 2004). This species produces fewer young that the Signal Crayfish and so is quickly out-competed in terms of population numbers. This species is also outcompeted by the invasive species Orconectes limosus. The annual catch of this species has dropped to a fraction of what it was prior to the introduction of crayfish plague (Westman 2002, Bohman Nordwall and Edsman 2006). This species was extensively produced but the plague has caused a significant decline of more than 95% during a period of nearly 150 years (Skurdal and Taugbøl 2002). The range of this species remains compromised by the crayfish plague (Holdich and Pockl 2007). Dredging of waterways in localised areas has further threatened this species as it leaves the water cloudy and disturbs the habitat (Füreder et al. 2006). Acid rain, also causing a decrease in water quality, is thought to be responsible for a decline in breeding success, as the egg cases of young crayfish are unable to form properly (Collins et al. 1983). Low calcium concentrations may be a factor limiting the distribution and production of this species in soft-water lakes (Rukke 2002). In Sweden, this species is estimated to have undergone a decline of ~78% over the last 22.5 years based on a decline from 1,724 known subpopulations in 1994, to 1,000 subpopulations in 2002 (Fiskeriverket and Naturvårdsverket 1998; Database of Crayfish Occurrences 2005). In Finland, the rate of decline is currently at about 20% every 20 years, though it may be greater (M. Pursiainen pers. comm. 2010). In Norway, this species is estimated to have undergone ~61% decline over the last 22.5 years from a 40 tonnes yield in 1966, to 10 tonnes in 1999 (Skurdal et al. 1999). While there is no available quantifiable data on the trends in Denmark, the situation is likely to be similar. Rates of decline in other countries are similar to that of the Scandinavian countries: ~67% decline over 10 years in Belgium (Arrignon et al. 1999), ~56% decline in Germany over 22.5 years, ~95% decline over 22.5 years in Hungary, and ~86% decline in the Netherlands over 22.5 years. Notable declines are reported for most of the other countries, other than Belarus where numbers are said to be increasing; Croatia where numbers are stable but non-native species have recently been introduced so future declines are expected; Slovakia where numbers are thought to be stable. These figures indicate that this species is likely undergoing a rate of decline of around 50-80% over a 22.5 year period. However, there are a number of large-scale re-stocking programs for this species and in some areas of its range, numbers are stable so the true rate of decline is likely closer to 30-50% globally. |
Conservation Actions: |
Astacus astacus has been previously assessed as Vulnerable by the IUCN Red List Index of Threatened Species (Version 2.3 of the Categories and Criteria), and is listed as Critically Endangered on the 2010 Red List of Swedish Species. This species is currently listed on the Danish Red List as "at risk from eradication due to crayfish plague" (S. Berg pers. comm. 2009). This species is also listed under a number of directives including the EU Habitats Directive Appendix V, and directive 92/43/EEC on the conservation of natural habitats and of wild fauna and flora. It therefore requires the designation of special areas of conservation for its protection. It is also listed under Appendix III of the Bern Convention. There has been wide-scale development of species action plans for A. astacus. At present, there is wide-scale re-stocking of this species into lakes from which it was formerly known. The import of live crayfish into Sweden from abroad is now prohibited. Restrictions on catch levels, gear-type use and minimum landing size exist in several countries (Taugbøl et al. 2004). Restocking in Sweden is taking place but is met with little success (L. Edsman pers. comm. 2010). Given the continuing population decline, several species protection programmes have been initiated (including re-stocking and re-introduction activities) in various parts of Austria (Füreder 2009). |
Citation: | Edsman, L., Füreder, L., Gherardi, F. & Souty-Grosset, C. 2010. Astacus astacus. The IUCN Red List of Threatened Species 2010: e.T2191A9338388. . Downloaded on 18 September 2018. |
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