Crayfish Fauna Research Articles

Alabama's Crayfish Species Count Reaches Century Mark: Confirmation of Procambarus barbiger Occurring in Alabama

Beginning in 2005, several projects were conducted to update our knowledge of the understudied crayfish fauna in Alabama. Numerous new crayfish records were secured that narrowed collection coverage gaps statewide and boosted records from under-sampled habitat types. The culmination of this work eventually led to publication of the comprehensive book Crayfishes of Alabama. Most of the material secured was identifiable and included numerous new state, drainage, and physiographic records. However, without Form I males, some material could not be verified to species. Specimens of 2 females that resembled Procambarus barbiger (Jackson Prairie Crayfish) were collected during those efforts, 1 each from 2 locations in Sumter County, AL, near the Mississippi state line. That species was unknown in the state at the time and was included in the book as a species that hypothetically could occur in the state. Post-publication, we collected a Form I male incidental to insect trapping at a third Sumter County location that verified the identification, bringing the state total to 100 known species.

Recurring infection by crayfish plague pathogen only marginally affects survival and growth of marbled crayfish

Invasive alien crayfish threaten the diversity of freshwater ecosystems and native crayfish fauna. In Europe, this is largely due to transmission of the crayfish plague to susceptible native crayfish. Many invasive species tolerate crayfish plague, but the infection still has the potential to reduce the fitness of a tolerant host due to energy trade-offs between immune response maintenance and life-history traits, such as growth and reproduction. In combination with other unfavourable conditions, such a response could alter further invasion success of an otherwise successful crayfish invader. We examined whether repeated infection with one of the most virulent haplogroups of crayfish plague agent (Aphanomyces astaci) affects growth or survival of the juvenile marbled crayfish (Procambarus virginalis). Juveniles were exposed to i) two levels of pathogen concentrations, and ii) two different feeding regimes under the higher pathogen concentration. In all performed trials, repeated infection reduced growth rates, while the combination of recurring infection and food limitation significantly increased mortality. The average energy cost of the immune response was estimated at 12.07 J/day for individuals weighing 0.3 grams. Since infections were frequent and pathogen concentrations high, results suggest that marbled crayfish is resistant to A. astaci pathogen and its survival is only affected by adding the stress of food limitation. The survival of almost half of the individuals exposed to high pathogen loads and extreme food limitation indicates that chronic infection by crayfish plague is unlikely to be an important factor impeding invasion success of the marbled crayfish, even under harsh conditions. Our results add to the growing body of evidence that marbled crayfish has potential to become one of the most successful freshwater invaders.

Epigean Crayfishes of the Greenbrier River Drainage, West Virginia

Although the distribution and status of West Virginia’s crayfishes has received more attention since the publication of Jezerinac et al.’s monograph of the state fauna in 1995, the crayfishes of the Greenbrier River Drainage have been neglected. Conservation concerns for imperiled crayfish fauna have increased in recent years. However, in order to form effective managements plans, a thorough understanding of the distribution and conservation status of a region's fauna is necessary. In order to establish this understanding of crayfish fauna within the Greenbrier River Drainage, the West Liberty University Crayfish Conservation Laboratory performed surveys during the summers of 2008 and 2009 within the drainage. These efforts have revealed new information regarding the distribution, life history, natural history, taxonomy, and conservation status of the complete assemblage of epigean crayfish species found in the Greenbrier River Drainage: Cambarus appalachiensis, C. carinirostris, C. chasmodactylus, C. smilax, Faxonius cristavarius, F. obscurus, F. sanbornii, and F. virilis. This novel information regarding the distribution and life history of the epigean crayfishes present within the drainage can be used to combat the major conservation threats affecting the native crayfish within the drainage including nonnative crayfishes, land-use practices, and pollutants. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

English

Abstract The invasive spiny-cheek crayfish (Faxonius limosus) has been able to colonize many European waterbodies since its first introduction into Europe, threatening the indigenous crayfish fauna. The remarkable reproductive plasticity of this species has been suggested as an important factor contributing to the alarming invasiveness of this species. In this study, we compared the reproductive strategies of an invasive (F. limosus) and a sympatric indigenous crayfish (Pontastacus leptodactylus). We questioned if the reproductive abilities, namely parthenogenesis and multiple paternity, may contribute to an ongoing invasion process in the Lower Danube. Using microsatellites, we genotyped the mothers and their offspring from 11 clutches of F. limosus and 18 clutches of P. leptodactylus. While no parthenogenesis has been found in F. limosus populations, multiple paternity has been detected for the first time in both species, with comparable incidence. The results of the study indicate that multiple paternity does not play a dominant role in the successful colonization of F. limosus in the Danube. However, the presented results have to be regarded as a pilot study, with a limited number of samples and loci investigated. Given the relevance of mating system knowledge for management measures, future studies with larger sample number could provide valuable contributions to ongoing conservation actions.

English

AbstractWe used existing collection records to summarize the current understanding of freshwater crayfish diversity in Virginia. Virginia includes both Atlantic slope drainages and tributaries of the Tennessee and Ohio Rivers which flow to the Gulf of Mexico via the Mississippi River. The state’s varied topography produces a wide range of freshwater habitats from mountain-side springs and seeps to rushing mountain streams to warm, turbid rivers and the lentic habitats of the coastal plain. We report distributional patterns of 31 species and one subspecies. About 20% of the species reported are introduced, one native species is federally listed as threatened, and several other taxa are species of conservation concern. A number of yet-to-be-described taxa with highly limited distributions will likely need protection. We hope the data included will prove useful in future efforts to understand the diversity of these fascinating and ecologically important animals in Virginia and will further the resolution of Virginia’s complete crayfish fauna.

Money Kills Native Ecosystems: European Crayfish as an Example

Native European crayfish conservation was triggered by invasion of crayfish plague disease agent,Aphanomyces astaci, starting 1860s in Northern Italy. Resulting crayfish plague epidemics quickly spread over Continental Europe, then to Finland, Sweden and finally, after running amok around Europe,A. astaciwas discovered also in Iberian Peninsula, Norway, Ireland, and United Kingdom in 1970s and 1980s. By that time significant proportion of native crayfish stocks had been lost, and while crayfish plague epidemics were still recorded, also industrialization and waterways construction were causing damage to remaining native crayfish stocks. While alien crayfish introductions, at leastFaxonius limosus, already gave rise to first wave of crayfish plague epidemics in late 19th century, later in 1960s it was decided that introductions of alienPacifastacus leniusculusshould be initiated to replace native European crayfish populations. Decisions were based on presumed advantages for fishery, suitable habitat requirements and supposed immunity againstA. astaci. Furthermore, conservation of native European crayfish species was sidelined and focus shifted toward alien crayfish stocking routine and consumption. Alien crayfish species introductions resulted in repeated waves of crayfish plague epidemics among remaining native crayfish stocks. It was soon discovered that alien crayfish of North American origin were, as suspected, permanent reservoirs forA. astaci, that some of those alien species were losing their resistance against selected strains ofA. astaciand struggled in European aquatic ecosystems. In this article, we introduce numerous motives behind grand mistake of introducing alien crayfish species to Europe and then promoting their stocks instead of focusing on conservation of native crayfish species. We outline how false economical, biological and ecologic assumptions were used to justify a hasty introduction of alien crayfish, which has further devastated native crayfish and also permanently changed European aquatic ecosystems, both with disastrous consequences. Lesson to be learnt is that science-based warnings about alien species damage to native ecosystems and native crayfish must be taken with utmost caution. Protection of native European crayfish should be core issue, not commercial activities. Finally, we summarize main threats and actions needed to protect remaining native freshwater crayfish fauna in Europe.

Genetic diversity, phylogenetic position and morphometric analysis of Astacus colchicus (Decapoda, Astacidae): a new insight into Eastern European crayfish fauna.

The phylogeny of European crayfish fauna, especially with respect to Eastern European species, is still far from being completely resolved. To fill this gap, we analyzed most of the European crayfish species focusing on the phylogenetic position of the endemic crayfish Astacus colchicus, inhabiting Georgia. Three mitochondrial and one nuclear marker were used to study evolutionary relationships among European crayfish species, resulting in the unique phylogenetic position of A. colchicus indicating independent species status to A. astacus. Phylogenetic analyses revealed a deep molecular divergence of A. colchicus in comparison to A. astacus (6.5-10.9% in mtDNA and 1.1% in nDNA) as well as to Pontastacus leptodactylus and P. pachypus (5.5-10.0% in mtDNA and 1.4-2.4% in nDNA). Absent ventral process on second male pleopod and abdominal somites II and III with pleura rounded lacking prominent spines clearly indicate taxonomic assignment to the genus Astacus; however, the species is distributed almost in the middle of Ponto-Caspian area typical by occurrence of the genus Pontastacus. Several morphological indices linked to head length, carapace, and total body length and width were found to demonstrate apparent differences between A. colchicus and A. astacus. Although this study provides a novel insight into European crayfish phylogeography, we also point out the gaps in comprehensive study of the P. leptodactylus species complex, which could reveal details about the potential species status of particular species and subspecies within this genus.

Changes to Kentucky's Crayfish Fauna Since 2004 with an Updated Checklist of Kentucky Crayfish Species

Kentucky's crayfish faunal list has undergone considerable changes since the publication of Crayfishes of Kentucky (Taylor and Schuster, 2004). We conducted an in-depth literature review and reviewed collection databases to develop an up-to-date checklist of crayfish species known to occur in Kentucky. Sixty-five crayfish species have been documented from Kentucky to date, including twelve new species described and three state records since 2004. One new species description (Faxonius sp. A. nov. sp.) is currently underway and was included in the species list for future reference. Additionally, we provide information on changes in crayfish taxonomy, crayfish species that may occur in Kentucky, and potential cryptic species where additional research may result in new species being detected. We hope this information provides clarity for researchers and resource managers and encourages additional crayfish research in Kentucky.

Towards a cohesive strategy for the conservation of the United States’ diverse and highly endemic crayfish fauna

Freshwater biodiversity of the United States has long been recognized for its high level of species richness. The US crayfish fauna is richer than that found in any other country or continent in the world. Crayfishes are critically important members of freshwater ecosystems and have long been utilized for human consumption. Combined, these factors argue for effective conservation. When compared to other diverse aquatic groups such as fishes or unionid mussels, conservation efforts for US crayfishes are lacking. We review here, knowledge gaps that prevent effective conservation and past and ongoing crayfish conservation and management activities. We conclude by proposing a strategy of actions to improve the conservation standing of this important group of organisms. These action items include improved outreach efforts, funding and research to fill numerous knowledge gaps, and the inclusion of crayfishes in broader scale aquatic conservation activities.

Conservation and Distribution of Creaserinus fodiens (Digger Crayfish) in Pennsylvania.

Because crayfishes are the 4th most imperiled group of aquatic or terrestrial organisms in North America, agency efforts to assess the status of the fauna have increased in recent decades. Historically these assessments have focused on stream-dwelling species while primary burrowing crayfishes have been overlooked. Pennsylvania has initiated numerous surveys to determine modern distributions and conservation status of its crayfish fauna and in 2014 began a primary burrowing crayfish survey. These efforts led to the first documented record of Creaserinus fodiens (the Digger Crayfish) in the state. In 2017 a dedicated effort to determine the distribution and conservation status of C. fodiens commenced in Erie and Crawford counties. Initially, visual surveys were conducted for suitable habitat (roadside ditch, ephemeral pool, wetland, etc.) and/or burrows with chimneys, with the goal of collecting presence/absence data. Sites with suitable habitat, burrows, or chimneys were subsequently sampled for crayfishes. If water depth was <0.25 m collections were made via dipnet and if water depth was ≥0.25 m the site was trapped for 3 months. Each site was analyzed for percentage of land use type using the National Land Cover Database with a 200 m diameter buffer. These data were modeled using logistic regression to elucidate habitat preferences of C. fodiens. NatureServe’s ranking system was used to designate conservation status in the state of Pennsylvania. Two populations of C. fodiens have been discovered to date with additional sampling to take place in 2019.

A Reassessment of the Crayfishes of Pennsylvania's Lake Erie Basin with an Emphasis on Zoogeography, Taxonomy, and Conservation.

An investigation is currently underway to reassess the crayfishes of the Lake Erie basin in northwestern Pennsylvania. A total of 54 stream sites were sampled, with a majority of the streams in the basin sampled at least once. Preliminary data have revealed that the most common crayfish species are Cambarus robustus (Big Water Crayfish), Faxonius propinquus (Northern Clearwater Crayfish), and Cambarus carinirostris (Rock Crayfish) respectively. Faxonius obscurus (Allegheny Crayfish) was discovered in one tributary to Elk Creek and a tributary to Lake Erie, not supporting prior belief that F. obscurus was forcing F. propinquus into smaller tributaries. Three additional species, Faxonius immunis (Calico Crayfish), Creaserinus fodiens (Digger Crayfish), and Cambarus spp. were collected via trapping. Procambarus acutus (White River Crayfish), an invasive crayfish species, was also collected via trapping. The presence of such a diverse crayfish fauna is likely due to the postglacial movement via stream and wetland migrations. The Lake Erie basin represents a range overlap for northern and southern crayfish species, and is a unique location within Pennsylvania’s watersheds.

Using maximum entropy modeling to predict suitable habitat locations for the Cutshin Crayfish (Cambarus taylori)

The Cutshin Crayfish (Cambarus taylori) is a recently described species which is endemic to the Middle Fork of the Kentucky River basin. The Middle Fork of the Kentucky River lies within the anthracite coal fields of Eastern Kentucky, and thus a conservation assessment of C. taylori is warranted. The goal of this study was to predict suitable habitat locations for C. taylori through use of maximum entropy modeling (MaxEnt). The Middle Fork of the Kentucky River’s crayfish fauna was surveyed during the summer of 2014. The occurrence data from this study coupled with landscape scale environmental variables—such as stream order and land use data—was used to create the model. The mean area under the receiver operating characteristic curve (AUC) value was 0.898, showing the model had high predictive accuracy. The model indicated high probability of occurrence in streams at the southern end of the basin, and a low probability of occurrence at the northern end of the basin. Stream order and stream sinuosity had the highest contribution to the model showing that C. taylori prefers 3rd and 4th order streams with low sinuosity. Although the AUC value showed high predictive accuracy for the model, predicted sites will need to be ground validated to confirm the model’s predictive accuracy.

Reassessment of the Crayfishes of the Upper Ohio River Basin in Pennsylvania.

Crayfishes are keystone species and ecosystem engineers in freshwater systems and are considered the third most imperiled taxa on the planet. In 1906, Arnold Ortmann published one of the most complete historic crayfish surveys ever conducted, which has allowed Pennsylvania to assess changes to crayfish fauna over the past century. More recently, waterways have been impacted by anthropogenic stressors such as urbanization and extractive industry. Our primary goal is to determine changes in species distributions and relative abundances of crayfishes in western Pennsylvania by visiting historical and new sites. Surveys in 2015-16 focused on collecting primary burrowers by trapping and burrow excavation. In 2017, efforts shifted to epigean species in the Upper Ohio River drainage, using standardized sampling of 10 seine hauls/site to assess 265 sites. Populations of primary burrowing crayfishes were found at 20% of 61 historical sites and 72% of 57 new collection sites. Of epigean crayfishes, 79% were found at 102 historical sites and 97% of 163 new sites. These collections represent approximately 60% of the survey, with remaining collections to occur in 2018. Important findings were three nonnative species: Faxonius rusticus (Rusty Crayfish), Procambarus clarkii (Red Swamp Crayfish), and Procambarus acutus (White River Crayfish). Preliminary data suggests that crayfish fauna in western Pennsylvania has remained moderately stable over the last century, though the presence of nonnative crayfishes indicates the need for continued monitoring. Efforts in Pennsylvania must focus on prevention and management of the spread of nonnative species to preserve the native crayfish populations that remain.

Crayfishes of the Potomac River Basin in West Virginia

The high level of endemism displayed by native crayfish taxa, in addition to the recognized displacement abilities of nonindigenous crayfish such as Faxonius virilis and Procambarus acutus represents a serious threat to indigenous crayfish populations. Other major conservation threats to native crayfish fauna in the eastern portion of West Virginia include land development and land-use practices. The goal of this study was to compare recent and historical species distributions and assess conservation standings of native and nonindigenous crayfishes of the Potomac River Basin in West Virginia. Between June and October of 2007 historical and semi-randomly selected sites were sampled throughout the basin. Abundance was determined by catch per unit effort (CPUE) for ten seine hauls. Morphometric data including total carapace length, propodus length, and palm length were recorded in millimeters for each species. Life history parameters were determined from collections made during the study. Native species collected included Cambarus bartonii, Cambarus carinirostris, and Faxonius obscurus. Introduced species collected included Faxonius virilis and Procambarus zonangulus. C. bartoni was present in the Cacapon, North Branch Potomac, Potomac Direct Drains, and South Branch Potomac. F. obscurus was absent from Potomac Direct Drains, and C. carinirostris was only present in the South Branch Potomac. F. virilis and P. zonangulus were only present in Potomac Direct Drains. Though F. limosus was reported in 1989, no specimens were recovered during over the course of this survey, which indicates possible extirpation from the West Virginia portion of its range.

English

Abstract Due to the increasing anthropogenic pressures and the introduction of invasive alien species, indigenous crayfish species are rarely found in the urban areas of big cities. The aim of this research was to study, for the first time, presence and distribution of freshwater crayfish in artificial lakes of the Maksimir Park, located in the centre of Zagreb, the capital of Croatia. Additionally, the goal was to estimate population size and structure, and analyse morphometric characteristics, the proportion of injuries and crayfish body condition. In 4 out of 5 lakes within the park, two crayfish species, Astacus astacus and Astacus leptodactylus, were recorded with no overlap in their distribution. Each species was established in two lakes in relatively abundant populations. Differences in body condition, sex ratio and proportion of injuries were recorded between species. Recorded differences are most likely the result of different trapping techniques applied, predation of alien invasive species of turtles and intraspecific competition. Obtained results will serve as a baseline for further research and monitoring of the crayfish fauna in the Maksimir lakes.

More evolution underground: Accelerated mitochondrial substitution rate in Australian burrowing freshwater crayfishes (Decapoda: Parastacidae)

To further understand the evolutionary history and mitogenomic features of Australia’s highly distinctive freshwater crayfish fauna, we utilized a recently described rapid mitogenome sequencing pipeline to generate 24 new crayfish mitogenomes including a diversity of burrowing crayfish species and the first for Astacopsis gouldi, the world’s largest freshwater invertebrate. Whole mitogenome-based phylogeny estimates using both Bayesian and Maximum Likelihood methods substantially strengthen existing hypotheses for systematic relationships among Australian freshwater crayfish with evidence of pervasive diversifying selection and accelerated mitochondrial substitution rate among the members of the clade representing strongly burrowing crayfish that may reflect selection pressures for increased energy requirement for adaptation to terrestrial environment and a burrowing lifestyle. Further, gene rearrangements are prevalent in the burrowing crayfish mitogenomes involving both tRNA and protein coding genes. In addition, duplicated control regions were observed in two closely related Engaeus species, together with evidence for concerted evolution. This study significantly adds to the understanding of Australian freshwater crayfish evolutionary relationships and suggests a link between mitogenome evolution and adaptation to terrestrial environments and a burrowing lifestyle in freshwater crayfish.

English

Abstract In 2015, a survey of Tomlinson Run State Park (TRSP) located in Hancock County, West Virginia USA was completed. Thirty stations, each 100m long, were randomly selected using ArcGIS for both intermittent and perennial stream reaches. Sites were sampled by performing ten seine hauls at each randomly selected station and scored using an Ohio EPA Qualitative Habitat Evaluation Index (QHEI) to obtain qualitative habitat data. Ponds and impoundments were trapped for crayfish using baited crayfish/minnow traps. Burrows found in wetlands and seeps were excavated to determine TRSP burrowing crayfish species composition. In total, 471 crayfish of four species (Cambarus carinirostris, Cambarus monongalensis, Cambarus robustus and Orconectes obscurus) were collected. A statistically significant correlation existed between QHEI score and CPUE for C. carinirostris on intermittent streams. Cambarus monongalensis was the sole burrowing species encountered while C. carinirostris was only collected from intermittent stations (CPUE = 0.12). O. obscurus was the most common species collected from perennial streams (CPUE = 0.95) while Cambarus robustus was the rarest species (CPUE = 0.09) encountered in Tomlinson Run State Park. The crayfish fauna of TRSP is typical for the Upper Ohio River Valley, and at the present time, all species appear stable.

Effects of Climate Change, Invasive Species, and Disease on the Distribution of Native European Crayfishes

Climate change will require species to adapt to new conditions or follow preferred climates to higher latitudes or elevations, but many dispersal-limited freshwater species may be unable to move due to barriers imposed by watershed boundaries. In addition, invasive nonnative species may expand into new regions under future climate conditions and contribute to the decline of native species. We evaluated future distributions for the threatened European crayfish fauna in response to climate change, watershed boundaries, and the spread of invasive crayfishes, which transmit the crayfish plague, a lethal disease for native European crayfishes. We used climate projections from general circulation models and statistical models based on Mahalanobis distance to predict climate-suitable regions for native and invasive crayfishes in the middle and at the end of the 21st century. We identified these suitable regions as accessible or inaccessible on the basis of major watershed boundaries and present occurrences and evaluated potential future overlap with 3 invasive North American crayfishes. Climate-suitable areas decreased for native crayfishes by 19% to 72%, and the majority of future suitable areas for most of these species were inaccessible relative to native and current distributions. Overlap with invasive crayfish plague-transmitting species was predicted to increase. Some native crayfish species (e.g., noble crayfish [Astacus astacus]) had no future refugia that were unsuitable for the modeled nonnative species. Our results emphasize the importance of preventing additional introductions and spread of invasive crayfishes in Europe to minimize interactions between the multiple stressors of climate change and invasive species, while suggesting candidate regions for the debatable management option of assisted colonization.

Conservation of Freshwater Crayfish in Australia

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.

Conservation and Management of Crayfishes: Lessons from Pennsylvania

AbstractNorth America's crayfish fauna is diverse, ecologically important, and highly threatened. Unfortunately, up‐to‐date information is scarce, hindering conservation and management efforts. In Pennsylvania and nearby states, recent efforts allowed us to determine the conservation status of several native crayfishes and develop management strategies for those species. Due to rarity and proximity to urban centers and introduced (exotic) crayfishes, Cambarus (Puncticambarus) sp., an undescribed member of the Cambarus acuminatus complex, is critically imperiled in Pennsylvania and possibly range‐wide. Orconectes limosus is more widespread; however, recent population losses have been substantial, especially in Pennsylvania, and northern Maryland, where its range has declined (retreated eastward) by greater than 200 km. Introduced congeners likely played a major role in those losses. Although extirpated from some areas, Cambarus bartonii bartonii remains widespread and is not an immediate conservation concern. In light of these findings, the role of barriers (e.g., dams), environmental protection, educational programs, and regulations in preventing crayfish invasions and conserving native crayfishes is discussed, and management initiatives centered on those factors are presented. The need for methods to eliminate exotics and monitor natives is highlighted. Although tailored to a specific regional fauna, these ideas have broad applicability and would benefit many North American crayfishes.