Patterns and determinants of phenotypic variability within two invasive crayfish species

2021 ◽  
Author(s):  
Iris Lang ◽  
Ivan Paz‐Vinas ◽  
Julien Cucherousset ◽  
Géraldine Loot
Keyword(s):  
Phenotypic Variability ◽  
Invasive Crayfish ◽  
Crayfish Species

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

2021 ◽  
Vol 9 ◽  
Author(s):  
Franziska Chucholl ◽  
Franziska Fiolka ◽  
Gernot Segelbacher ◽  
Laura Saskia Epp
Keyword(s):  
Population Size ◽  
Detection Rate ◽  
Large Scale ◽  
Survey Methods ◽  
Source Population ◽  
Invasive Crayfish ◽  
Stream Size ◽  
Spatio Temporal ◽  
Large Scale Screening ◽  
Crayfish Species

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.

scholarly journals First Detection of the Crayfish Plague Pathogen Aphanomyces astaci in Costa Rica: European Mistakes Should Not Be Repeated

2021 ◽  
Vol 9 ◽  
Author(s):  
Laura Martín-Torrijos ◽  
Angel Jose Correa-Villalona ◽  
Juan Carlos Azofeifa-Solano ◽  
Fresia Villalobos-Rojas ◽  
Ingo S. Wehrtmann ◽  
...  
Keyword(s):  
Costa Rica ◽  
Procambarus Clarkii ◽  
Freshwater Ecosystems ◽  
Future Research ◽  
Warning Sign ◽  
Aphanomyces Astaci ◽  
Molecular Approaches ◽  
Research Activities ◽  
Invasive Crayfish ◽  
Crayfish Species

The crayfish plague pathogen Aphanomyces astaci is one of the main factors responsible for the decline in European and Asian native crayfish species. This pathogen was transported to these regions through its natural carriers, North American crayfish species, which were introduced during the last century. Since then, the carrier species and the pathogen have spread worldwide due to globalization and the highly invasive nature of these species. In Europe, five carrier species have been categorized as high-risk as they are responsible for the loss of provisioning services, which endangers freshwater ecosystems. The red swamp crayfish Procambarus clarkii, in particular, is currently one of the most concerning species as its spread threatens crayfish biodiversity and freshwater ecosystems worldwide. In this study, we describe the first detection of A. astaci in an introduced population of P. clarkii in Central America, specifically in Costa Rica. Using molecular approaches, we analyzed 48 crayfish samples collected from Reservoir Cachí and detected the presence of A. astaci in four of these samples. The introduction of P. clarkii and the incorrect management of the species (related to its fishery and the commercialization of live specimens) over the past decades in Europe are mistakes that should not be repeated elsewhere. The detection of the pathogen is a warning sign about the dangerous impact that the introduction of this invasive crayfish may have, not only as a carrier of an emerging disease but also as a direct risk to the invaded ecosystems. Our results may serve to (1) assess current and future consequences, and (2) direct future research activities, such as determining the potential impacts of A. astaci on native decapod species, or on other introduced crayfish species that are used for aquaculture purposes, such as Cherax quadricarinatus.

scholarly journals Behavioral Responses to 'Alarm Odors' In Potentially Invasive and Non-invasive Crayfish Species from Aquaculture Ponds

Behaviour ◽  
2004 ◽  
Vol 141 (6) ◽  
pp. 691-702 ◽  
Author(s):  
William Daniels ◽  
Francesca Gherardi ◽  
Patrizia Acquistapace
Keyword(s):  
The Other ◽  
Control Phase ◽  
Food Odor ◽  
Non Invasive ◽  
Aquaculture Ponds ◽  
Invasive Crayfish ◽  
Food Odors ◽  
Conspecific Odors ◽  
Procambarus Acutus ◽  
Crayfish Species

AbstractTwo North American crayfish species, the Eastern white river crayfish, Procambarus acutus acutus, and the red swamp crayfish, P. clarkii, were studied in the laboratory for their responses to food odors and to cues released by injured conspecifics and heterospecifics. The two species differ in that only P. clarkii is known to behave as an invasive species. All the test individuals were collected from aquaculture research ponds, in which they had had no prior contact with the other species and predation risks, excluding cannibalism, were reduced. The experimental design consisted in subjecting 20 crayfish per species to (1) a 3-min control phase after the injection of 20 ml of water and (2) a 3-min test phase after the injection of 20 ml of one of three test solutions (food odor, conspecific odor plus food odor, heterospecific odor plus food odor). We found that the two species differ on one hand for their background behavior and on the other for the intensity and quality of their responses to the three types of cues. Firstly, P. clarkii appeared more active than P. acutus acutus during the control phase and responded in a stronger fashion to the injection of the solutions. Secondly, we recorded an increased locomotion in P. acutus acutus with food and heterospecific cues (by moving crayfish maximize the chance of finding food), but not with conspecific odors (by not moving, crayfish reduce their exposure to visual predators). To the contrary, at the injection of the three test solutions P. clarkii displayed clear feeding-related activities (although less intense with conspecific odors) as opposed to the danger reactions shown in a previous study on individuals from a naturalized population of the same species. This result suggests that crayfish reared in an environment where predation risks are reduced (e. g. in aquaculture ponds) may respond differently to cues that in other, more risky habitats inform of a danger.

Prevalence of the crayfish plague, Aphanomyces astaci Schikora, in alien crayfish species in Japan

2020 ◽  
Vol 25 (1) ◽  
pp. 31-37
Author(s):  
Kensuke Kamimura ◽  
Tadashi Kawai
Keyword(s):  
Water Temperature ◽  
Procambarus Clarkii ◽  
Severe Disease ◽  
Pacifastacus Leniusculus ◽  
Infection Prevalence ◽  
Infection Status ◽  
Aphanomyces Astaci ◽  
Invasive Crayfish ◽  
The Relationship ◽  
Crayfish Species

Abstract Crayfish plague is a severe disease of crayfish that is caused by the oomycete Aphanomyces astaci. Two crayfish hosts of this parasite, Procambarus clarkii and Pacifastacus leniusculus, were imported from North America into Japan and were found to be infected with this parasite. Since the endemic Japanese crayfish, Cambaroides japonicus, has a low resistance to the crayfish plague, infection with this parasite will likely lead to crayfish death. Specimens of both invasive crayfish species were collected across Japan and their infection status was examined using a PCR technique. Aphanomyces astaci was detected in all localities and the average infection prevalence was 67%. Additionally, when the signs of melanization were compared with the results from PCR analyses, it suggested that the DNA detection procedure is more reliable than observation of tissue melanization. Moreover, the relationship between prevalence and water temperature in the field was analyzed, indicated that water temperature influenced the prevalence of A. astaci infection.

scholarly journals Measures to Control Invasive Crayfish Species in Switzerland: A Success Story?

2020 ◽  
Vol 8 ◽  
Author(s):  
Raphael Krieg ◽  
Alex King ◽  
Armin Zenker
Keyword(s):  
Population Density ◽  
Water System ◽  
Predatory Fish ◽  
Success Story ◽  
The Past ◽  
Invasive Crayfish ◽  
Negative Impacts ◽  
Native Crayfish ◽  
Crayfish Species

Invasive crayfish species were first documented in Switzerland in the 1970s. Today, North American crayfish species dominate in most major lakes and streams in Switzerland. In combination with the crayfish plague, they pose a substantial threat to our native crayfish. Over the past 20 years, various techniques have been applied to reduce negative impacts of these invasive crayfish in Switzerland: eradication (temporary drainage or destruction of a water system, biocides), suppression (intensive trapping, electricity introduction of predatory fish) and containment (construction of crayfish barriers). Temporary drainage or filling-in of isolated ponds, in combination with calcium hydroxide application has been successful in eradicating populations of invasive crayfish. However, trapping and introduction of predatory fish led to a reduction in population density but neither method has ever caused the extinction of a population. Invasive crayfish have not yet reached crayfish barriers, therefore, long-term functionality of these barriers still needs to be proven. Nevertheless, functional controls with native crayfish have shown that barriers prevent their upstream movement. Implementation of crayfish barriers is the most promising method to protect native crayfish from displacement by invasive crayfish species. Many measures are expensive, time consuming, and show little or no success in controlling invasive crayfish. Therefore, we recommend to focus on implementing drastic measures, such as filling-in or draining of isolated waters or a combination of various methods to maximise the reduction of population size.

scholarly journals Agonism and shelter competition between invasive and indigenous crayfish species

2004 ◽  
Vol 82 (12) ◽  
pp. 1923-1932 ◽  
Author(s):  
Francesca Gherardi ◽  
William H Daniels
Keyword(s):  
Procambarus Clarkii ◽  
Reproductive Potential ◽  
Limited Resource ◽  
Indigenous Species ◽  
Laboratory Studies ◽  
Freshwater Biodiversity ◽  
Future Studies ◽  
Invasive Crayfish ◽  
Procambarus Acutus ◽  
Crayfish Species

Several crayfish species behave as biological invaders. Their establishment in an area has frequently been accompanied by the reduction or elimination of indigenous species. A laboratory study was designed to investigate whether the invasive crayfish Procambarus clarkii (Girard, 1852) is dominant over the indigenous (to Delaware) crayfish Procambarus acutus acutus (Girard, 1852) in either the absence or the presence of a shelter as a limited resource. As expected, we found that P. clarkii is more aggressive than the similarly sized P. a. acutus, thus confirming previous studies that demonstrated an inherent dominance of the invasive over the indigenous crayfish. We then hypothesized that species showing a lower preference for an offered shelter (P. clarkii) should be less motivated to defend it. To the contrary, in a competitive context P. clarkii excluded P. a. acutus from the shelter but did not use the resource. Caution must be used in extrapolating these laboratory studies to the field, and future studies should analyze multiple factors, including the autoecology of the two species and their reproductive potential and recruitment patterns. However, our results might help in highlighting the risks for freshwater biodiversity created by the uncontrolled translocations of P. clarkii and other similar invasive species.

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