Crayfish Species Research Articles

Genetic Haplotype Mapping of the Allegheny Crayfish (Faxonius obscurus)

Non-indigenous species are a significant threat to freshwater biodiversity. In the Potomac Basin there are several known invasive crayfish species including F. virilis (virile crayfish) and F.rusticus (rusty crayfish). It is imperative to discover whether F. obscurus is in fact an invasive crayfish that needs a management plan or simply another native species that needs protection. F. obscurus is a wide-ranging crayfish species that is native to the northeastern United States. Populations found in the Atlantic Slope Drainage basins are considered invasive. Using CO1 and 16S primers, we will be creating a range-wide haplotype map to investigate these invasions.

Water Quality Monitoring for the Central Appalachian Coalfields Crayfish

Primary economic drivers over the years in the central Appalachian coalfields include coal mining, timbering, fossil fuel extraction, and all-terrain vehicle tourism. These industries cause impacts such as sedimentation, elimination of headwater streams (resulting from valley fills), destruction of riparian vegetation, and increased physiochemical pollution in montane streams. As a result of this significant habitat destruction, two species of endemic crayfishes, Cambarus callainus and Cambarus veteranus, were both federally listed in April 2016. This study will sample 12 selected sites – four degraded streams, four medium-impacted streams, and four reference condition streams – within the coalfields region of Kentucky, Virginia, and West Virginia. Sampling will occur for one year, alternating monthly between two sets of six sites. General crayfish sampling will occur at each site to document the crayfish community present. Water quality monitoring will be split into four categories: long-term, point-source, photometer, and water samples analyzed for heavy metal content. Understanding the chemical composition of the target species’ habitat will enable us to properly and efficiently aid C. callainus and C. veteranus conservation efforts.

Using Crayfish Burrows to Illustrate Simple Ecological Field Techniques

Ecological field techniques such as transect surveys are long-used, integral means of immersing students in field exercises to illustrate ecological measures. Many species of crayfish create conspicuous burrows within or near aquatic habitats. Such burrows can easily be identified and measured by students during an ecological field exercise. In this article, we describe a field activity we developed as part of a college-level course in which students utilized transects and calipers to collect counts and measurements of crayfish burrows in order to evaluate their distribution and size among different substratum types along a small stream. This field exercise could be incorporated, with or without modification, into an applicable high school or introductory/intermediate college biology course as a means of illustrating ecological concepts, sampling technique, and/or behavioral biology.

A Behavioral Study of Lacunicambarus thomai in a Field

Crayfish respond rapidly to environmental changes, this responsiveness to environmental changes makes them good detectors for degradation in the environment. Contaminants in the environment may influence crayfish by making them absent in what would be prime habitat. It may also affect the population densities of areas by decreasing the number of individuals in area that superficially look like prime habitat. This study was conducted on Lacunicambarus thomai in a field setting to gather information on the life history of a primary burrowing species of crayfish. Some pre-existing information on the behavior and parts of the life history of Lacunicambarus thomai were incomplete and, in some cases, incorrect. The data showed that what was perceived to be a fully nocturnal species or spends most of its time underground may not necessarily true. Findings of this study conflicted on multiple instances with the previously believed notions. This project provides a better understanding of the life history of a primary burrowing crayfish species: the life history of primary burrowing crayfish has been less than stream dwelling species. This could lead to more studies being conducted on other species to obtain a better understanding of this elusive type of crayfish. The results of this study could be used to get a baseline of the basic life history of these animals as well as other types of burrowing crayfish species.

How well does NATURA 2000 protect threatened stone crayfish in Croatia?

The stone crayfish Austropotamobius torrentium (Schrank, 1803) is a threatened native European freshwater crayfish species for which Natura 2000 network represents the most important conservation effort at the European level. In Croatia, there are altogether 25 Natura 2000 sites defined specifically for this species. In the present study, we aimed to assess the effectiveness of Natura 2000 sites in preserving stone crayfish diversity through gap analysis, a GIS-based approach that overlays species distribution data on a map of designated Natura 2000 sites. Our results showed that the existing Natura 2000 network in Croatia encompasses most of the areas with a high diversity of A. torrentium; currently designated sites harbour 73.3% of recorded A. torrentium populations. Future conservation planning efforts, and possible expansion of Natura 2000, should be focused on newly discovered A. torrentium populations that present divergent evolutionary lineages.

Laboratuvar koşullarında yetiştirilen kırmızı bataklık kerevitinin (Procambarus clarkii) ilk sol yürüme bacağında bir uzantı anormalliği

Red swamp crayfish (Procambarus clarkii) is the most cultivated crayfish species in the world that has commercial importance for both aquaculture and aquarium industries. In this study, a case report of an appendage abnormality observed in the left cheliped of a female specimen (6.92 g) reared under laboratory conditions is presented. It has been determined that the specimen has two appendages in the left cheliped root. Of these appendages, the right one (1.27 cm) ends in a blunt. On the left (1.06 cm), a spiny structure similar to that of the fourth and fifth walking legs was observed

Introduction of Southern White River Crayfish (<i>Procambarus zonangulus</i>) to New Brunswick

Southern White River Crayfish (Procambarus zonangulus), an aquatic, potentially invasive species, is documented from New Brunswick for the first time. It was found in a small, privately owned, lake in the Saint John River system that was apparently stocked for recreational purposes with non-native fish and the crayfish. Procambarus zonangulus has successfully overwintered at the site for at least a year and, more likely, for several years. This is the third species of non-native crayfish recorded in New Brunswick, joining Spiny-cheeked Crayfish (Faxonius limosus) and Virile Crayfish (Faxonius virilis). This is also the first persisting introduction for the genus Procambarus in Canada of which we are aware.

EDNA Detection of Native and Invasive Crayfish Species Allows for Year-Round Monitoring and Large-Scale Screening of Lotic Systems

Effective management of both endangered native and invasive alien crayfishes requires knowledge about distribution, monitoring of existing and early detection of newly established populations. Complementary to traditional survey methods, eDNA sampling has recently emerged as a highly sensitive non-invasive detection method to monitor crayfish populations. To advance the use of eDNA as detection tool for crayfish we used a twofold approach: 1) we designed a novel set of specific eDNA-assays for all native (Austropotamobius torrentium, Austropotamobius pallipes, Astacus astacus) and the most relevant invasive crayfish species (Pacifastacus leniusculus, Faxonius limosus, Faxonius immunis) in Central Europe. To ensure specificity each primer pair was tested in silico, in vitro, and in situ; 2) we assessed the influence of spatio-temporal variables (distance to upstream population, season, stream size) on eDNA detection in seven streams using two different detection methods (qualitative endpoint PCR and quantitative droplet digital PCR, ddPCR). The newly developed eDNA assays successfully detected all crayfish species across different lotic and lentic habitats. eDNA detection rate (endpoint PCR) and eDNA-concentration (ddPCR) were significantly influenced by distance and season. eDNA detection was successful up to 7 km downstream of the source population and across all seasons, although detectability was lowest in winter. eDNA detection rate further decreased with increasing stream size. Finally, eDNA-concentration correlated positively with estimated upstream population size. Overall, we provide near operational eDNA assays for six crayfish species, enabling year-round detection, which represents a clear benefit over conventional methods. Due to its high sensitivity, eDNA detection is also suitable for the targeted search of as-yet unrecorded or newly emerging populations. Using quantitative ddPCR might further allow for a rough estimation of population size, provided that the identified spatio-temporal factors are accounted for. We therefore recommend implementing eDNA-detection as a complementary survey tool, particularly for a large-scale screening of data-deficient catchments or a year-round monitoring.

Nutrient and anti-nutrient composition of processed crayfish (Atya gabonensis) from river Benue, Nigeria.

The species of crayfish identified as (Atya gabonensis) along River Benue Nigeria and were captured and analyzed for nutrient and antinutrient content including, proximate composition (crude protein, crude fat, crude fiber, ash, and moisture content), as well as vitamin A, Vitamin B components, Vitamin C, Vitamin D, vitamin E, Vitamin K and select mineral concentrations. Additionally, some important antinutrients in crayfish were also examined. The proximate composition showed that moisture content was (9.54%), protein was (7.46%), Crude fibre was (5.60%), fat was (1.57%) and ash was (2.47%) respectively. This was found to be rich in protein and considerably high amount of moisture content. The anti-nutrient composition analysis revealed the presence of Saponin (0.471mg/100g), Alkaloid (3.905mg/100g), flavonoid (0.675mg/100g), tannin (0.017mg/100g), Phytate (0.060mg/100g), Oxalate (0.005mg/100g) and others, all of which are below toxic level. For mineral and vitamin compositions, potassium was significantly (P>0.05) higher than iron, zinc, magnesium, calcium and phosphorus while vitamin C was (4.920mg/100g) which is higher than all other vitamins evaluated. Based on these findings crayfish (Atya gabonensis) is recommended for consumption and for further investigation as a potential raw material for the pharmaceutical industry.Keywords: Atya gabonensis, Nutrient, Anti nutrient, River Benue,composition

Invasive crayfish outperform Potamonautid crabs at higher temperatures

Abstract Data on ecological impacts of freshwater crayfish invasions in Africa are scarce but invasion history suggests the likelihood of negative implications for biodiversity. To evaluate the potential for ecological impacts we describe the consumer‐resource dynamics of two established crayfish species (Cherax quadricarinatus and Procambarus clarkii) in comparison with the native trophic analogue, the freshwater crab Potamonautes perlatus preying upon Clarias gariepinus fry using comparative functional responses (FRs) and FR ratio (FRR). Experiments were conducted under dark and light conditions as well as low (19°C) and high (28°C) temperature treatments. All three species exhibited potentially population destabilising Type II (hyperbolic) FRs towards prey, which was significantly higher in the dark than in the light. At low temperatures, P. perlatus exhibited the highest maximum feeding estimate although the FR curve was not significantly different from C. quadricarinatus at the highest prey densities. Both crayfish species had higher attack rates at both temperatures and consumed significantly more prey at the high temperature than P. perlatus. The FRR of both crayfish species at the high temperature treatment was higher than that of P. perlatus due to high attack rate and low handling parameters. At 19°C, P. perlatus had a higher or negligible relative FR magnitude compared to P. clarkii and C. quadricarinatus respectively, which suggests some degree of biotic resistance at this temperature; however, this resistance is decreased at 28°C. Cherax quadricarinatus consistently had disruptive FR parameters across both temperatures. Findings from this study represent an important step towards understanding the impacts of crayfish in Africa for public authorities and environmental managers. The two invasive crayfish species have the potential to exert greater per capita impacts on benthic prey communities in invaded systems as shown by their high FRs and FRRs. Furthermore, C. quadricarinatus is an emerging invader globally and our results provide evidence of potential for negative ecological impact regardless of thermal conditions. African countries and their respective environmental managers should therefore maximise efforts to prevent the introduction and spread of these invaders to conserve native biodiversity.

Year-round monitoring and large-scale screening of native and invasive crayfishes in lotic systems

Freshwater crayfish are among the most threatened animal taxa in Central Europe. Effective conservation measures for endangered native and management of invasive alien crayfishes requires knowledge about distribution, monitoring of existing and early detection of newly established populations. eDNA has recently emerged as a promsing, highly sensitive, and non-invasive detection tool in this regard. To evaluate eDNA as detection tool for freshwater crayfish, we developed a novel set of specific eDNA-assays for all native (Austropotamobius torrentium, Austropotamobius pallipes, Astacus astacus) and the most relevant invasive crayfish species (Pacifastacus leniusculus, Faxonius limosus, Faxonius immunis) in Central Europe. To ensure specificity each primer pair was tested in silico, in vitro, and in situ, including a total of 13 lotic and lentic waterbodies (Fig. 1). Moreover, we assessed the influence of spatio-temporal variables (distance to upstream population, season, and stream size) on eDNA detection in seven streams using two different detection methods (qualitative endpoint PCR and quantitative droplet digital PCR, ddPCR). The newly developed eDNA assays successfully detected all crayfish species across different lotic and lentic habitats. Multiple linear mixed-effects analysis revealed a significant effect of distance and season on eDNA detection rate (endpoint PCR) and eDNA-concentration (ddPCR). Year-round detection was successful up to 7 km downstream of the source population, although detectability was lowest in winter. eDNA detection rate further decreased with increasing stream size. Finally, eDNA-concentration correlated positively with estimated upstream population size. Overall, our study provides easily applicable eDNA assays for six crayfish species, enabling year-round detection, which represents a clear benefit over conventional methods. Due to its high sensitivity, eDNA detection is also suitable for the targeted search of as-yet unrecorded or newly emerging populations. Using quantitative ddPCR might further allow for a rough estimation of population size, provided that the identified spatio-temporal factors are accounted for. We therefore recommend implementing eDNA-detection as a complementary survey tool, particularly for a large-scale screening of data-deficient catchments or a year-round monitoring (Chucholl et al. 2021).

Gill morphology and formulae of crayfishes (Decapoda: Astacidea: Parastacidae) from New Guinea and New Zealand and a comparison with other selected species of crayfishes

AbstractThe Infraorder Astacidea comprises four superfamilies of decapod crustaceans: the freshwater Astacoidea and Parastacoidea and the marine Enoplometopoidea and Nephropoidea. The gill morphology of four species of crayfishes belonging to Astacoidea and Parastacoidea, two coral reef species of Enoplometopoidea, and 2 deep-water species of Nephropoidea are described and illustrated for comparisons and to determine characters characteristic to members of the family Parastacidae (Parastacoidea) from New Guinea. Morphology of the arthrobranchs and pleurobranchs were similar among all species, having a single stem with filament, but podobranchs of the parastacoideans differed from those of Astacoidea, being corrugated and tubular and having filaments. The astacoidean P. virginalis had a plate-like lamella with filament. The two nephropoid and two enoplometopoid species were similar to each other; their podobranch had a flat blade-like lamella without a filament and a shaft with a filament. The gill formulae of the New Guinea species of Cherax were the same as those of the Australian congeners, but the formula of the New Zealand Paranephrops planifronsWhite, 1842 was the same as those of the South American parastacids.

No country for native crayfish: importance of crustaceans in the diet of native and alien Northern raccoons

The Northern raccoon Procyon lotor is a native mesocarnivore of North America which has been introduced to many Eurasian countries, where invasive populations currently occur. Regarding Italy, the species is present in Lombardy and in the Foreste Casentinesi National Park (Tuscany and Emilia-Romagna). In this work, we conducted a review on food habits of the Northern raccoon both in the native and in the introduced ranges, and we firstly reported the evidence on the impact of this species on native crayfish in Central Italy. We retrieved 18 papers published between 1932 and 2020, 14 from the native range and four from the invasive range. We analysed the frequency of occurrence of nine food categories (mammals, birds, reptiles, amphibians, fish, insects, crustaceans, fruits, and others). After fruits, crustaceans (where available) were the main food items detected in raccoon scats (up to 60% of the total diet, in the frequency of occurrence). In September 2019, we detected a total of 37 dead adult freshwater white-clawed crayfish Austropotamobius pallipes complex in Central Italy, with evident signs of predation by the Northern raccoon. The local population of Northern raccoon is fast expanding its range, whereas the local population of A. pallipes complex is declining. This crayfish species is protected by national and international laws. Thus, a monitoring program involving all stakeholders and institutions dealing with in environmental management, aiming at removing all raccoons currently present in this area of Central Italy, should be carried out in the short term to limit the potential impacts exerted by the fast-spreading of this invasive mammal.

ПРОМЫСЛОВАЯ ФАУНА ВОДОЕМОВ БАССЕЙНА Р. МОСКВЫ ВО ВТОРОЙ ПОЛОВИНЕ XVIII В.

Based on the data from economic notes to the General Land Survey, the ranges of commercial fish and crayfish species that inhabited waterbodies of the Moscow River basin in the second half of the 18th century are reconstructed. Eighteen maps showing the distribution of 22 fish species, including Acipenser ruthenus L., Abramis brama L., Barbatula barbatula L., Lota lota L., Sander lucioperca L. and others are compiled. Comparison of commercial fish species that lived in the Moscow River basin in the second half of the 18th century with data from ichthyological studies in the beginning of the XXI century and materials of archaeological surveys shows that almost all of these species have lived in the Moscow River basin since ancient times and have survived to the present day.

Force and Boldness: Cumulative Assets of a Successful Crayfish Invader

Multiple causes can determine the disturbance of natural equilibrium in a population of a species, with a common one being the presence of invasive competitors. Invasives can drive native species to the resettlement of the trophic position, changing reproduction strategies or even daily normal behaviours. Here, we investigated the hypothesis that more effective anatomical features of an intruder (Faxonius limosus) come with increased boldness behaviour, contributing to their invasion success in competition against the native species (Pontastacus leptodactylus). We tested the boldness of specimens representing the two species by video-based assessment of crayfish individuals’ attempts to leave their settlement microenvironment. The experiment was followed by a series of measurements concerning chelae biometry, force and muscle energetics. The native species was less expressive in terms of boldness even if it had larger chelae and better muscular tissue performance. In contrast, because of better biomechanical construction of the chelae, the invasive species was capable of twice superior force achievements, which expectedly explained its bolder behaviour. These findings suggest that, in interspecific agonistic interactions, the behaviour strategy of the invasive crayfish species is based on sheer physical superiority, whereas the native crayfish relies on intimidation display.

Environmental nitrate impacts foraging and agonistic behaviours of invasive non-native crayfish (Pacifastacus leniusculus and Faxonius virilis)

Invasive species often co-occur in nature and positive or negative interactions among them can affect community structure and ecosystem functioning. Outcomes depend on the intrinsic traits of the species involved and on how species’ performance is affected by the environmental conditions of the recipient ecosystem. Here, we investigated the impact of nitrate, a nutrient common in urban and agricultural sewage discharges, on two invasive crayfish species (Pacifastacus leniusculus and Faxonius virilis) co-occurring in a Nitrate Vulnerable Zone in the UK. Crayfish were exposed to two ecologically relevant nitrate concentrations (≤ 10 and 50 mg NO3−/l) and seven traits relating to foraging success and interspecific interactions were assessed. During monospecific experimental trials, elevated nitrate had a similar impact on the foraging efficacy of P. leniusculus and F. virilis, reducing their ability to sense and find food. However, during dyadic interspecific competition experiments, higher nitrate caused a greater reduction in the number of aggressive behaviours of F. virilis towards P. leniusculus. As such, changes in environmental nitrate regime may affect interactions between these invasive species in regions of sympatry with consequences for their respective invasion dynamics and the wider ecosystem.

Modelling effects of disturbance on population dynamics of generalized crayfish life history strategies

Abstract Crayfish play a crucial ecological role and are often considered a keystone species within freshwater ecosystems; however, North American crayfish species face disturbance and ecological threats including invasive species and intensified drought. Demographic models can allow examination of population dynamics of a targeted species under a wide variety of disturbance scenarios. In this study, crayfish population dynamics were modelled and their responses to simulated biological invasions and drought were assessed. As life history data on crayfish are relatively rare, models were used to explore the population viability of four generalized species with distinct life history strategies under 11 disturbance scenarios. RAMAS‐Metapop was used to construct stage‐based demographic metapopulation models parameterized using vital rates from established literature sources. Models indicated that populations respond differentially to disturbance based on life history. However, both r‐ and K‐selected species appear to be highly susceptible to decline when faced with the additive effects of reduced carrying capacity resulting from invasion and reduced survival rates caused by drought. Constructing models that explore a broad array of life histories and disturbance regimes can provide managers with tools to develop generalized, widely applicable conservation strategies in data‐depauperate systems.

Functional traits explain crayfish invasive success in the Netherlands

Biological invasions by nonindigenous species can have negative effects on economies and ecosystems. To limit this impact, current research on biological invasions uses functional traits to facilitate a mechanistic understanding of theoretical and applied questions. Here we aimed to assess the role of functional traits in the progression of crayfish species through different stages of invasion and determine the traits associated with invasive success. A dataset of thirteen functional traits of 15 species currently occurring or available for sale in the Netherlands was evaluated. Six of these crayfish appeared invasive. Important traits distinguishing successful from unsuccessful invaders were a temperate climate in the native range, a medium to high egg count and producing more than one egg clutch per year. The most successful invaders had different functional trait combinations: Procambarus clarkii has a higher reproductive output, can migrate over longer distances and possesses a higher aggression level; Faxonius limosus is adapted to a colder climate, can reproduce parthenogetically and has broader environmental tolerances. Using a suit of functional traits to analyse invasive potential can help risk management and prevention. For example, based on our data Procambarus virginalis is predicted to become the next successful invasive crayfish in the Netherlands.

The Pontastacus leptodactylus (Astacidae) Repeatome Provides Insight Into Genome Evolution and Reveals Remarkable Diversity of Satellite DNA.

Pontastacus leptodactylus is a native European crayfish species found in both freshwater and brackish environments. It has commercial importance for fisheries and aquaculture industries. Up till now, most studies concerning P. leptodactylus have focused onto gaining knowledge about its phylogeny and population genetics. However, little is known about the chromosomal evolution and genome organization of this species. Therefore, we performed clustering analysis of a low coverage genomic dataset to identify and characterize repetitive DNA in the P. leptodactylus genome. In addition, the karyogram of P. leptodactylus (2n = 180) is presented here for the first time consisting of 75 metacentric, 14 submetacentric, and a submetacentric/metacentric heteromorphic chromosome pair. We determined the genome size to be at ~18.7 gigabase pairs. Repetitive DNA represents about 54.85% of the genome. Satellite DNA repeats are the most abundant type of repetitive DNA, making up to ~28% of the total amount of repetitive elements, followed by the Ty3/Gypsy retroelements (~15%). Our study established a surprisingly high diversity of satellite repeats in P. leptodactylus. The genome of P. leptodactylus is by far the most satellite-rich genome discovered to date with 258 satellite families described. Of the five mapped satellite DNA families on chromosomes, PlSAT3-411 co-localizes with the AT-rich DAPI positive probable (peri)centromeric heterochromatin on all chromosomes, while PlSAT14-79 co-localizes with the AT-rich DAPI positive (peri)centromeric heterochromatin on one chromosome and is also located subterminally and intercalary on some chromosomes. PlSAT1-21 is located intercalary in the vicinity of the (peri)centromeric heterochromatin on some chromosomes, while PlSAT6-70 and PlSAT7-134 are located intercalary on some P. leptodactylus chromosomes. The FISH results reveal amplification of interstitial telomeric repeats (ITRs) in P. leptodactylus. The prevalence of repetitive elements, especially the satellite DNA repeats, may have provided a driving force for the evolution of the P. leptodactylus genome.

Only one can remain? Environmental and spatial factors influencing habitat partitioning among invasive and native crayfishes in the Pannonian Ecoregion (Hungary)

Biological invasions have increasingly threatened indigenous species, influence metacommunity organisation and consequently, global biodiversity. World-wide expansion of non-indigenous crayfish (NICS) is associated with dramatic changes in species poor indigenous crayfish (ICS) assemblages challenging conservation planning. We analysed long-term changes of crayfish occurrences from the pre-invasion state, through the first appearance of NICS, to their intensive spread in Hungarian waters. Further, we analysed present-day crayfish metacommunity patterns for co-occurrences and influence of spatial and environmental factors. Historic data revealed a marked pre-invasion decline in indigenous noble crayfish Astacus astacus and stone crayfish Austropotamobius torrentium populations, but not in the narrow-clawed crayfish Pontastacus leptodactylus. Historic data provided no direct evidence for the impact of NICS on ICS, rather it supported that NICS often entered areas where ICS had been extinct or were not present at all. Crayfish species extremely rarely co-occurred which could indicate their strong competition and be related to utilization of empty sites by NICS. Crayfish metacommunities were predominantly spatially structured indicating the primary influence of ongoing invasion. Crayfish species also exhibited different environmental preferences mainly along the altitude and temperature gradients. We conclude that the invasion is still in the expanding phase and without an effective conservational program the future of ICS is doubtful in Hungary. Conservation policy should focus on the preservation and reintroduction of the stone and noble crayfishes in highland refugees. Expansion of NICS should be prevented in refugee areas by utilizing possibilities provided by natural and artificial barriers, and education and strict ban should be simultaneously applied to prevent further illegal releases by aquarists.