Key-words: crayfish distribution, indigenous species, invasive species, native range, mapsRecently published astacological studies substantially improved available data on distribution of crayfish in various European regions. At the same time, spread of invasive species has been recorded, additional nonindigenous species became established in various countries, and losses of populations of native species due to crayfish plague and other negative factors were observed. We overview recent advances in this knowledge, and provide updated colour maps of the distribution of all crayfish species present in Europe. These maps are originally based on the data from the Atlas of Crayfish in Europe published in 2006 as a result of the CRAYNET project, and were further updated from more recently published reports, grey literature, and especially thanks to contributions and feedback of over 70 specialists from 32 countries. Separate maps are available for all indigenous crayfish species in Europe as well as for three most widespread non-indigenous crayfish species. Additionally, two maps give locations of known findings of crayfish species introduced to Europe after 1980. These newly established alien species have so far restricted distributions; however, the frequency of recent reports suggests that findings of such species resulting from releases of aquarium pets will further increase. RÉSUMÉ Répartition à l'échelle continentale des espèces d'écrevisses en Europe : mises à jour et cartes Mots-clés :distribution des écrevisses, espèces indigènes, espèces envahissantes, Les études astacologiques récemment publiées ont sensiblement amélioré les données disponibles sur la distribution des écrevisses dans les différentes régions européennes. Dans le même temps, la propagation des espèces envahissantes a été enregistrée, des espèces non indigènes supplémentaires se sont établies dans différents pays, et des pertes de populations d'espèces indigènes en raison de la peste des écrevisses et d'autres facteurs négatifs ont été observées. Nous synthétisons les progrès récents dans la connaissance, et fournissons des cartes en couleur mises à jour de la distribution de toutes les espèces d'écre-visses présentes en Europe. Ces cartes sont à l'origine basées sur les données de l'Atlas des écrevisses en Europe publié en 2006 à la suite du projet CRAYNET, et ont ensuite été mises à jour à partir des études publiées plus récemment, de la

Metal pollution is a global problem which represents a growing threat to the environment. Because of bioaccumulation and negative effects of heavy metals, their bioavailability needs to be monitored. Many studies showed accumulation of metals in crayfish tissues as dose-and time-dependent without significant differences in tissue concentration levels comparing males and females. Muscles and exoskeleton were considered as specific for accumulation of mercury and nickel, respectively. Cadmium, zinc, copper, lead, and chromium accumulated mainly in hepatopancreas. By analyzing these specific tissues, it is possible to deduce the bioavailability and, by presumption, the level of environmental pollution by specific metals. However, in the case of zinc and copper, their utility is limited to assessing bioavailability because rapid depuration of these metals renders them less useful for long-term environmental monitoring programs. The literature reporting heavy metal impacts on freshwater crayfish, with reference to accumulation levels, is reviewed and summarized with respect to their suitability as bioindicators. Summarized published data from unpolluted or control localities can be used as referential values in crayfish, and consequently help with evaluation of monitored sites.

Businesses in the pet trade collect and transport many aquatic species around the globe, and some of these individuals are released into new habitats. Some jurisdictions have introduced laws intended to regulate this trade, but these regulations have rarely had the desired effects. Laws regarding pets and the pet trade are often poorly communicated, poorly enforced, and not aligned with hobbyists' beliefs. Consequently, some laws may increase the number of unwanted introductions instead of decreasing them. A significant change in approach is needed, involving far greater communication with scientists, administrations, politicians, the pet industry, and pet owners, promoting euthanasia of unwanted pets rather than release, and the creation and promotion "white lists" of low risk species that can be sold in the pet trade.

International audienceThe oomycete Aphanomyces astaci is generally considered a parasite specific to freshwater crayfish, and it has become known as the crayfish plague pathogen. Old experimental work that reported transmission of crayfish plague to the Chinese mitten crab Eriocheir sinensis, and the ability of A. astaci to grow in non-decapod crustaceans, has never been tested properly. * We re-evaluated the host range of A. astaci by screening for the presence of A. astaci in two crab species cohabiting with infected crayfish in fresh waters, as well as in other higher crustaceans from such localities. The animals were tested with species-specific quantitative PCR, and the pathogen determination was confirmed by sequencing of an amplified fragment of the nuclear internal transcribed spacer. Furthermore, we examined microscopically cuticle samples from presumably infected crab individuals for the presence of A. astaci-like hyphae and checked for the presence of pathogen DNA in such samples. * Screenings of benthopelagic mysids, amphipods and benthic isopods did not suggest infection by A. astaci in non-decapod crustaceans. In contrast, both studied lake populations of crabs (a native semiterrestrial species Potamon potamios in Turkey, and an invasive catadromous E. sinensis in Sweden) were infected with this parasite according to both molecular and microscopic evidence. * Analyses of polymorphic microsatellite loci demonstrated that A. astaci strains in the crabs and in cohabiting crayfish belonged to the same genotype group, suggesting crayfish as the source for crab infection. * The potential for A. astaci transmission in the opposite direction, from crabs to crayfish, and potential impact of this pathogen on populations of freshwater crabs require further investigations, because of possible consequences for crayfish and freshwater crab conservation and aquaculture

Morphology of the crayfish spermatozoon and of the spermatophore wall during three stages of final maturation including freshly ejaculated, post-mating, and after spermatozoa release was studied and compared. The crayfish spermatophore consists of a sperm mass enveloped by a three layered spermatophore wall. After mating, the thickness of the outer layer of the spermatophore is increased. The matrix in the middle layer of the spermatophore becomes reticulated, and granules inside this layer release their contents. Fibers in the inner layer degrade to small particles. The spermatozoon capsule swells and the space between the capsule and the spermatozoon appears. The area of the plasma membrane is increased by wrinkling of the surface and alteration from a single to a multilayered structure at the anterior part of the acrosome. The density of the subacrosome zone increases in the vicinity of the main body of the acrosome. With the onset of fertilization, the layers of the spermatophore are dissolved by female glair gland secretions. The spermatozoon extracellular capsule, plasma membrane, and membranous lamellae are eliminated, and bundles of filaments are released from anterior part of the acrosome. The subacrosome zone loses electron density and retracts. The electron-dense material of the innermost layer of the acrosome is discharged and, together with acrosome filaments, forms a filament/droplet structure at the anterior part of the spermatozoon. The most important change is observed in the subacrosome zone, which may play a key role in the fertilization. Also, morphological changes of the spermatozoon that occur after release from the capsule, especially formation of the filament/droplet structure, may contribute to the mechanism of egg-spermatozoon binding in the crayfish, representative of animals with non-motile spermatozoa.

Freshwater biodiversity is globally threatened by various factors while severe weather events like long-term droughts may be substantially devastating. In order to remain in contact with the water or stay in a sufficiently humid environment at drying localities, the ability to withstand desiccation by dwelling in the hyporheic zone, particularly through vertical burrowing is crucial. We assessed the ability of three European native and five non-native crayfish as models to survive and construct vertical burrows in a humid sandy-clayey substrate under a simulated one-week drought. Three native species (Astacus astacus, A. leptodactylus, and Austropotamobius torrentium) suffered extensive mortalities. Survival of non-native species was substantially higher while all specimens of Cherax destructor and Procambarus clarkii survived. The native species and Pacifastacus leniusculus exhibited no ability to construct vertical burrows. Procambarus fallax f. virginalis and P. clarkii constructed bigger and deeper burrows than C. destructor and Orconectes limosus. In the context of predicted weather fluctuations, the ability to withstand desiccation through constructing vertical burrows into the hyporheic zone under drought conditions might play a significant role in the success of particular crayfish species, as well as a wide range of further hyporheic-dwelling aquatic organisms in general.

Numerous freshwater crayfish species are known to become successful invaders when introduced to new territories. One of the most invasive species in this group is the red swamp crayfish, Procambarus clarkii (Girard, 1852). In addition to other characteristics facilitating its invasiveness, it is also a vector of crayfish plague, a disease mostly lethal to crayfish of non‐North American origin. Procambarus clarkii, at present the most widespread crayfish species globally, is popular in many countries both for human consumption and as an ornamental animal. An established population of this species was documented for the first time within Indonesia, representing the first record for maritime Southeast Asia. The species is also common in the local ornamental pet trade. Infection by the crayfish plague pathogen Aphanomyces astaci Schikora was confirmed both in the outdoor population of P. clarkii and in one of the surveyed pet shops. Furthermore, A. astaci was detected in specimens of freshwater crab and shrimp species coexisting with P. clarkii. Local climatic conditions and the species temperature requirements suggest a high probability of the establishment of P. clarkii in Indonesia. Its further spread could irreversibly damage populations of many native endemic crustaceans in the country (as well as elsewhere in the region), and the thriving local aquacultures of the redclaw crayfish Cherax quadricarinatus (von Martens, 1868) may also be threatened. The total ban of P. clarkii and other crayfish species of North American origin in Indonesia is strongly recommended, especially considering that aquaculture and trade with Australasian species is a viable alternative option.

Many populations of the narrow-clawed crayfish Astacus leptodactylus in Turkey, including those inhabiting Lake Eg irdir, declined drastically in the mid-1980s due to introduction of crayfish plague Aphanomyces astaci. However, unlike many other localities, there has been some recovery in the A. leptodactylus population inhabiting this lake even though crayfish plague has been suspected to have persisted since then. In support of this, DNA from 5 of 34 healthy-looking crayfish sampled recently from the lake tested positive by both conventional and real-time PCR using species-specific primers targeting the rDNA internal transcribed spacer region, and product sequence analysis confirmed the identification of A. astaci. This complies with other recent reports of coexistence of native European crayfish with this pathogen, and further research is now needed to identify the key mechanisms allowing it.KEY WORDS: Aphanomyces astaci · Astacus leptodactylus · Host−pathogen coexistence · Melanisation · rDNA-internal transcribed spacer sequence · Lake Eg irdir Resale or republication not permitted without written consent of the publisherDis Aquat Org 98: [255][256][257][258][259] 2012 dramatically reduced. However, there were exceptional cases where crayfish numbers either remained continuously high or recovered enough to sustain commercial harvesting despite the presumed presence of the crayfish plague pathogen (Rahe & Soylu 1989, Harliog lu 2004, 2008.Crayfish resistance and/or unique water chemistries have been assumed as reasons facilitating the long-term coexistence of Aphanomyces astaci in crayfish inhabiting such lakes (Rahe & Soylu 1989, Harliog lu 2008. A. astaci was unambiguously proven as the cause of crayfish mortalities in the 1980s (Baran & Soylu 1989, Rahe & Soylu 1989, Huang et al. 1994. However, its later presence in Turkish lakes (e.g. Aydin & Dilek 2004, Harliog lu 2004, 2008 has only been assumed from symptoms that are not specific for the crayfish plague pathogen (Cerenius et al. 1988, Oidtmann et al. 1999. As A. astaci should not survive at a locality when its crayfish hosts disappear (Söderhäll & Cerenius 1999) and its presence in Turkey after 1989 has not been proven definitively, its distribution in the country might now be more restricted than assumed.The narrow-clawed crayfish population inhabiting Lake Eg irdir (Isparta Province; 38°N, 31°E, altitude 917 m above sea level [a.s.l.], area 482 km 2 ) collapsed in 1986, presumably due to crayfish plague (Fürst & Söderhäll 1987). By 1999, numbers recovered sufficiently to allow commercial harvesting, although catch sizes have been lower and prone to fluctuations (Fig. 1). The aim of this study was to examine Lake Eg irdir crayfish using PCR and rDNA sequence analysis to test for the contemporary presence of A. astaci. MATERIALS AND METHODSOver 2 occasions in 2009, a total of 32 crayfish (mean body length ± SD: 111 ± 22 mm) were caught in fyke-net traps in the southern part of Lake Eg irdir (37°53' N, 30°53' E). In March, 2 egg-bearing fem...