scholarly journals Should Redclaw Crayfish be introduced to Fiji?

1995 ◽  
Vol 2 (4) ◽  
pp. 312
Author(s):  
Roger Lowery
Keyword(s):  
Pacifastacus Leniusculus ◽  
River Systems ◽  
Cherax Quadricarinatus ◽  
Austropotamobius Pallipes ◽  
Aphanomyces Astaci ◽  
Large Populations ◽  
New Locations ◽  
The Uk ◽  
Native Crayfish ◽  
Redclaw Crayfish

Whenever a new organism comes on the aquaculture scene there is a rush to try it out and to introduce the species to new locations. Such was the case with Pacifastacus leniusculus in Europe in the early 1980s. In the UK there was at the time no legislation to control such introductions and commercial pressures ensured that the species was soon widely distributed throughout the UK. One consequence was the introduction of the Crayfish Plague Aphanomyces astaci which resulted in the destruction of large populations of the native crayfish Austropotamobius pallipes in several river systems. It was against this background that I came to learn of a proposal to introduce Cherax quadricarinatus to Fiji in 1991. The commercial proposal was put to the Department of Fisheries who were considering accepting it when, on the basis of experience with crayfish in the UK, I proposed that there should be a delay while the species was evaluated for its likely effect on the Fijian fauna.

Relaxed attitude towards spreading of alien crayfish species affects protection of native crayfish species: case studies and lessons learnt from a Fennoscandian viewpoint

2020 ◽  
Vol 25 (1) ◽  
pp. 39-46
Author(s):  
Japo Jussila ◽  
Lennart Edsman
Keyword(s):  
Competitive Advantage ◽  
Pacifastacus Leniusculus ◽  
Astacus Astacus ◽  
Signal Crayfish ◽  
Aphanomyces Astaci ◽  
Noble Crayfish ◽  
Native Crayfish ◽  
Chronic Carrier ◽  
Highly Virulent ◽  
Crayfish Species

Abstract The spreading of the alien signal crayfish (Pacifastacus leniusculus) is posing an ongoing threat to native European crayfish species in Fennoscandia, like the native noble crayfish (Astacus astacus). The signal crayfish is commonly a chronic carrier of the crayfish plague (Aphanomyces astaci), thus, in addition to being more competitive than noble crayfish, it also has a competitive advantage in this disease over the noble crayfish. The challenges rising from the introduction of the alien signal crayfish to Sweden, Finland and finally also Norway, are similar in nature. The licensed and unlicensed spreading of this species also has a similar history in these countries. In this paper we describe some of the patters of the spread of alien signal crayfish and highlight the detrimental nature of an alien crayfish, accompanied by a highly virulent disease, to native Fennoscandian crayfish and also to native Fennoscandian ecosystems. A halt to the further spreading of alien signal crayfish in Fennoscandia is the only means to ensure successful conservation outcomes for the noble crayfish.

scholarly journals The prevalence of Aphanomyces astaci in invasive signal crayfish from the UK and implications for native crayfish conservation

Parasitology ◽  
2017 ◽  
Vol 144 (4) ◽  
pp. 411-418 ◽  
Author(s):  
J. JAMES ◽  
S. NUTBEAM-TUFFS ◽  
J. CABLE ◽  
A. MRUGAŁA ◽  
N. VIÑUELA-RODRIGUEZ ◽  
...  
Keyword(s):  
Average Rate ◽  
Signal Crayfish ◽  
Aphanomyces Astaci ◽  
Virulent Strains ◽  
Pathogen Prevalence ◽  
Crayfish Population ◽  
To Come ◽  
Group B ◽  
The Uk ◽  
Native Crayfish

SUMMARYThe crayfish plague agent, Aphanomyces astaci, has spread throughout Europe, causing a significant decline in native European crayfish. The introduction and dissemination of this pathogen is attributed to the spread of invasive North American crayfish, which can act as carriers for A. astaci. As native European crayfish often succumb to infection with A. astaci, determining the prevalence of this pathogen in non-native crayfish is vital to prioritize native crayfish populations for managed translocation. In the current study, 23 populations of invasive signal crayfish (Pacifastacus leniusculus) from the UK were tested for A. astaci presence using quantitative PCR. Altogether, 13 out of 23 (56·5%) populations were found to be infected, and pathogen prevalence within infected sites varied from 3 to 80%. Microsatellite pathogen genotyping revealed that at least one UK signal crayfish population was infected with the A. astaci genotype group B, known to include virulent strains. Based on recent crayfish distribution records and the average rate of signal crayfish population dispersal, we identified one native white-clawed crayfish (Austropotamobius pallipes) population predicted to come into contact with infected signal crayfish within 5 years. This population should be considered as a priority for translocation.

The spatial distribution of Aphanomyces astaci genotypes across Europe: introducing the first data from Ukraine

2020 ◽  
Vol 25 (1) ◽  
pp. 77-87 ◽  
Author(s):  
Elena Ungureanu ◽  
Michaela MojŽiŠovÁ ◽  
Michiel Tangerman ◽  
Mihaela C. Ion ◽  
Lucian Parvulescu ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Middle East ◽  
Eastern Europe ◽  
Pacifastacus Leniusculus ◽  
Signal Crayfish ◽  
Aphanomyces Astaci ◽  
Western Palaearctic ◽  
Native Crayfish ◽  
Available Information ◽  
Mass Mortalities

Abstract Aphanomyces astaci is the causative agent of crayfish plague, a disease responsible for numerous mass mortalities of native crayfish across Europe. In this study, we aim to extend knowledge about the A. astaci distribution in Eastern Europe, with specific focus on the River Dnieper (Ukraine), and summarize presently available information about the distribution of genotypes of this pathogen across the Western Palaearctic. We compiled published records about genotype groups of A. astaci, assembled them to a comprehensive map, and added the newly obtained results from Ukraine. The native narrow-clawed crayfish Pontastacus leptodactylus was sampled from the river Dnieper in Svydivok and Kiev, ca 170 km apart, and screened for the pathogen presence in soft cuticles by quantitative PCR. We confirmed infections by A. astaci at both sites, with prevalence exceeding 30% and low to medium agent levels in infected crayfish. Pathogen genotyping confirmed the presence of the A. astaci haplogroup B, associated with the signal crayfish Pacifastacus leniusculus but also known from some chronically infected narrowclawed crayfish from Turkey and Moldova. Our results support the notion that latent A. astaci infections among narrow-clawed crayfish populations may be widespread in Eastern Europe and the Middle East.

scholarly journals Efficient Bayesian inference of fully stochastic epidemiological models with applications to COVID-19

2021 ◽  
Vol 8 (8) ◽  
pp. 211065
Author(s):  
Yuting I. Li ◽  
Günther Turk ◽  
Paul B. Rohrbach ◽  
Patrick Pietzonka ◽  
Julian Kappler ◽  
...  
Keyword(s):  
Bayesian Inference ◽  
Information Matrix ◽  
Monte Carlo Sampling ◽  
Epidemiological Models ◽  
Large Populations ◽  
Model Evidence ◽  
Age Structured ◽  
The Uk ◽  
Functional Central Limit

Epidemiological forecasts are beset by uncertainties about the underlying epidemiological processes, and the surveillance process through which data are acquired. We present a Bayesian inference methodology that quantifies these uncertainties, for epidemics that are modelled by (possibly) non-stationary, continuous-time, Markov population processes. The efficiency of the method derives from a functional central limit theorem approximation of the likelihood, valid for large populations. We demonstrate the methodology by analysing the early stages of the COVID-19 pandemic in the UK, based on age-structured data for the number of deaths. This includes maximum a posteriori estimates, Markov chain Monte Carlo sampling of the posterior, computation of the model evidence, and the determination of parameter sensitivities via the Fisher information matrix. Our methodology is implemented in PyRoss, an open-source platform for analysis of epidemiological compartment models.

scholarly journals A parvo-like virus in cultured redclaw crayfish Cherax quadricarinatus from Queensland, Australia

2002 ◽  
Vol 50 ◽  
pp. 79-86 ◽  
Author(s):  
RO Bowater ◽  
M Wingfield ◽  
A Fisk ◽  
KML Condon ◽  
A Reid ◽  
...  
Keyword(s):  
Cherax Quadricarinatus ◽  
Redclaw Crayfish
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