The native Australian crayfish Cherax quadricarinatus (or Redclaw) is a large, highly fecund and fast growing species that has been widely translocated both interstate and internationally. This paper describes a translocated population of the species in Lake Ainsworth, an acidic coastal window lake in New South Wales. This population now represents the southern-most extent of its translocated range within Australia, and coincides with two native crayfishes, Cherax cuspidatus and a highly imperilled species of Tenuibranchiurus. Consistently high trap catches and collection of berried females indicates that the population in Lake Ainsworth is large, well established and self-sustaining. The probable pathway of introduction to the lake was by human action (deliberate or accidental), rather than natural dispersal from previous sites of introduction. Native crayfish were not captured in the lake, but their presence was confirmed in ephemerally connected habitats〜2-3 km away. There are serious concerns about the further spread of the highly invasive C. quadricarinatus and its potential to displace native species.

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The yabby, Cherax destructor, is endemic to inland waterways of south-eastern Australia. However, as a result of aquaculture feral populations have become established outside its natural range, within and outside of Australia. In recent years, numerous translocated populations have been recorded from coastal drainages in New South Wales, where a sizeable diversity of endemic coastal crayfishes occur. Translocated yabbies represent a potential threat to indigenous fauna in the waterways of eastern New South Wales, and in this paper we outline the habitats and biota that may be at risk. We discuss several key concerns regarding this translocated crayfish, including: the probable pathways of introduction; its propensity to spread; potential competition and predation threats; pathogen concerns; and potential impacts at the habitat and ecosystem level.

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In addition to predicted changes in climate, more frequent and intense severe weather events (e.g. tropical cyclones, severe storms and droughts) have been identified as serious and emerging threats to the World's freshwater crayfish. This paper documents a single, high intensity rainfall event (in an area known for phenomenal rainfall events) that led to a flash flood and mass mortality of Euastacus valentulus in the Numinbah Valley of southeast Queensland in 2008. Several hundred crayfish died after evidently being swept away and entrapped in vegetation or buried in alluvium during this single extremely high flow event. In light of our observations, it is clear that severe weather events have the capacity to substantially impact/deplete freshwater crayfish populations. This emerging climate-driven threat is seen as particularly significant for freshwater crayfish species that occupy single localities with highly restricted ranges. Clarification of geographic ranges would allow a priority list of the most "at risk" populations, which could prove useful in a management response to severe weather events, which are predicted to be more frequent in future.

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Recent conservation assessments rank the world's freshwater crayfish in the five most endangered animal groups, and the Australian fauna as the most endangered of all the world's crayfish. In this paper, we introduce the 135 described species of freshwater crayfish in Australia, and provide an overview of this fauna and their current IUCN Red List conservation status. The Australian crayfish fauna is almost entirely endemic, and displays enormous variation in biology, distribution and ecology. Some Australian species are the world's fastest growing, most highly fecund and widely distributed crayfishes, and are tolerant of extreme variation in environmental conditions. Conversely, Australia is also home to many crayfish that are remarkably slow growing, late maturing and poorly fecund. Many species have highly restricted distributions and require specific environmental conditions that restrict them to particular areas and habitat types. These crayfish face a wide range of existing and emerging threats, and we discuss the research imperatives, practical actions, legislative changes and collaboration required to facilitate the recovery of crayfish populations.

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Unprecedented rates of extinction have lead to the development of fields, such as conservation genetics, in an attempt to better understand biodiversity and consequently devise conservation programs to maintain the genetic integrity of species. We discuss the utility and application of conservation genetics, using examples from Australian freshwater crayfish, with a view to applying this methodology to the sole native crayfish species found in Japan, Cambaroides japonicus (De Haan). This species is threatened by the non-indigenous crayfish Pacifastacus leniusculus (Dana) through displacement, competition pressures, and susceptibility to Aphanomyces astaci Schikora (the crayfish plague, carried by the invasive species). Examining the genetic diversity within C. japonicus could allow populations of high conservation priority to be identified (i.e., genetically distinct populations) or, in contrast, show that this species is genetically homogenous. Such genetic continuity may suggest that other conservation methods (e.g., translocations and restocking populations) may be suitable for this species of crayfish. Identifying genetic variability, or lack thereof, is a key step in dictating the future direction of any conservation measures for C. japonicus.

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Two new species of the crayfish genus Cherax are described from Whitsunday Island in the Coral Sea, Cherax austini sp. n. and Cherax cid sp. n. These two island species are similar to the 'C. depressus' species group from the Queensland mainland, differing in spination of the chelipeds and the development of the rostral ridges and sternal keel. Remarkably, Cherax austini sp. n. displays faint development of a median ridge on the cephalon, a feature otherwise associated with the disjunct and phylogenetically distinct fauna from the extreme south-west of Western Australia. Genetic analyses supported the close relationship of these two new species to the 'C. depressus' group from the mainland, with a comparatively recent divergence event between these two island species.

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Pacifastacus gambelii (Girard, 1852) is re-described and illustrated on the basis of the syntypes and additional material recently collected from Idaho, USA. A detailed distribution of the species is presented based on the data from voucher specimens and previous literatures. A lectotype is designated, and full synonymies are provided.

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The underground water level which shows annual changes is a potential factor restricting the habitat of the endangered Japanese crayfish, Cambaroides japonicus (De Haan, 1841) However, this factor in habitats of Japanese crayfish has not been previously monitored. We introduce an adapted method to measure the underground water level (hyporheic zone) in the streambed of brooks, and discuss the influence of this factor on the habitat use by Japanese crayfish.

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Pacifastacus nigrescens (Stimpson, 1857) is re-described and illustrated on the basis of materials collected from the Pacific slope states of USA. Detail of the distribution of the species and its conservation status are examined based on data from voucher specimens. Full synonymies are provided.

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Straightforward and inexpensive analysis of blood constituents can provide quantifiable information on sub-lethal stress in an animal and a measure of their overall physical fitness. Such methods have been widely used on a range of marine and terrestrial species, primarily those of commercial or recreational importance. Freshwater crayfish in many regions of the world face a common suite of threats and threatening processes that include: exotic species (including other freshwater crayfish, associated diseases and parasites), habitat fragmentation and destruction, anthropogenic pollution, overexploitation and increased environmental temperature. Although some studies have investigated the effects of these on freshwater crayfish in-part (i.e., measured by gross symptoms), the subtle, often asymptomatic physiological effects are poorly understood. The analysis of haemolymph provides a simple, inexpensive, high resolution, portable (i.e., suitable for field analysis and assessment in remote areas) and non-lethal method for the evaluation of sub-lethal stress and immunocompetence status in freshwater crayfish. There is considerable scope for application of these existing techniques in conservation initiatives for rare and endangered freshwater crayfish in Australasia, in particular by providing: i) non-lethal stress assessments, ii) quantification of compromised health and iii) increased understanding of the physiological impacts from key threats and threatening processes.

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Astacopsis gouldi (Clark) is native to northern Tasmania, Australia. It is the world's largest freshwater crayfish, potentially attaining a weight of greater than 6 kg and a carapace length (CPL) in excess of 240 mm. Field collection of A. gouldi and the recording of moulting events and growth have allowed an estimate of life history up to 3 kg. The majority of A. gouldi moult at least biennually, with the exception of the largest animals (over 5 kg). The results of this study suggest that a 190 mm CPL A. gouldi male is approximately 20 years of age. The maximum size is estimated to be reached at 30-35 years of age. This paper examines the life history of the crayfish species and the issues and solutions to the decline in its populations.

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Austropotamobius pallipes, the only native crayfish species in the UK, has declined over the past 30 years mainly due to the introduction and subsequent spread of Pacifastacus leniusculus, a North American species, which carries crayfish plague. This paper examines the reasons for the rapid decline of native crayfish and summarises a recent scoping study to determine how the remaining A. pallipes populations can be safeguarded.

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In Japan alien crayfish (the signal crayfish Pacifastacus leniusculus and the red swamp crayfish Procambarus clarkii) have increased. Alien crayfishes have a major impact on Japanese freshwater ecosystems, and new methods for protection and conservation are needed. I give the Information as a kind of conservation by using on culinary use of edible.

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The red swamp crayfish Procambarus clarkii was imported into Japan from New Orleans, Louisiana, USA, in 1927, and is now distributed across the Japanese Archipelago. This crayfish has been commonly used as a teaching material with a specific academic purpose in elementary schools. P. clarkii has body color variants, including an albino form with a relatively transparent body that is particularly suitable for examining the internal structures, such as digestive organs, beating heart and ovaries in female, without need for dissection. P. clarkii, as a non-native species, has potential negative effects on the native aquatic eco-system: hence this species must be treated with great care and an environmental education using such a crayfish is important in Japan. We describe how we have applied P. clarkii crayfish to an elementary science education in Japan.

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As an engineer of physical processes instead of biotic processes, Cambaroides japonicus is very important in mountain stream ecosystems. Additionally, the small stream habitats of the species continue to disappear. It is very important to determine environmental conditions in these small streams to conserve and manage C. japonicus habitats. The aims of this study were to document the environmental characteristics of small creek habitats using physical data. Principle components analysis (PCA) was used to examine patterns in the physical structure of small creeks and streams. Differences in physical variables between habitat types were examined. The second axis from the PCA, which was positively correlated with flow velocity and substrate coarseness, indicated that these habitats are characterized by erosional and depositional gradients. Stream habitats were significantly deeper and faster than habitats in small creeks. Our data also show that C. japonicus inhabits small creeks with fine substrate and without boulders.

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