J. Jussila

University of Eastern Finland | UEF · Department of Environmental and Biological Sciences

An ecological disaster based on human ignorance of scientific facts: the deliberate introduction of alien crayfish to Europe is a classic case of solving an ecosystem problem created by a mistake by making another. The devastation of the native European crayfish populations was a result of accidental introduction of crayfish plague (Aphanomyces ast...

Objectives: Crayfish plague disease, caused by the oomycete pathogen Aphanomyces astaci represents one of the greatest risks for the biodiversity of the freshwater crayfish. This data article covers the de novo transcriptome assembly and annotation data of the noble crayfish and the marbled crayfish challenged with Ap. astaci. Following the control...

Background: For over a century, scientists have studied host-pathogen interactions between the crayfish plague disease agent Aphanomyces astaci and freshwater crayfish. It has been hypothesised that North American crayfish hosts are disease-resistant due to the long-lasting coevolution with the pathogen. Similarly, the increasing number of latent...

Raputaru kertoo tarinan jokiravun kohtalosta ympäristömuutosten, rapuruton ja täpläravun paineessa. Opettavainen tarina korostaa luonnon merkitystä ja kotoperäisten lajien uhanalaista asemaa ja muistuttaa hyvinvoivan luonnon merkityksestä meille kaikille. Löytyy katseltavaksi täältä: https://www.youtube.com/watch?v=bJp9w0cEUNk.

We are discussing the matters related to the definitions and practicalities of species, in this case being crayfish, to be either alien or native. A species can not be both. We are also discussing the implications of native or alien definitions been applied to practical cases. One of our main aims is to halt the alien species to be called native.

An educational animation based on the story of noble crayfish and its fate in the hands of the crayfish plague and signal crayfish. A story on the effects of the alien crayfish species on European aquatic ecosystems and native crayfish. It is here: https://www.youtube.com/watch?v=oZLIaCJOwPo

Vesistön raputilanne selville pelkästä vesinäytteestä - tieteiskirjallisuutta vai todellisuutta. Se on mahdollista jo nyt, mutta kenties rutiinia tulevaisuudessa. Jokirapujen ja täplärapujen sekä rapuruton esiintymistä vesistössä on alustavasti selvitetty uudella eDNA-menetelmällä.

Freshwater ecosystem functioning is often thought to be dominated by fish, determining the community structure via top-down control and ecosystem engineering. However, freshwater crayfish can have an even stronger effect on food web and ecosystem functioning, operating as keystone species in a water body (Longshaw and Stebbing, 2016). As environmen...

The crayfish plague disease agent, Aphanomyces astaci, has coevolved with the native European crayfish since its arrival to mainland Europe in the 1860s. There are indications that some of the A. astaci strains are of reduced virulence, while the resistance against A. astaci infection varies among native European crayfish stocks. In Lake Venesjärvi...

Freshwater ecosystem functioning is often thought to be dominated by fish, determining the community structure via top-down control and ecosystem engineering. However, freshwater crayfish can have an even stronger effect on food web and ecosystem functioning, operating as keystone species in a water body (Longshaw & Stebbing, 2016). As environmenta...

Aphanomyces astaci is an Oomycete pathogen listed amongst the 100 worst invasive species worldwide. It was first introduced into Europe with invasive North American crayfish species and caused the collapse of numerous native freshwater crayfish populations. It is hypothesised that some of the first A. astaci strains to reach Europe, belonging to ha...

The introduction of North American freshwater crayfish and their hitchhiking pathogen Aphanomyces astaci into Europe has led to several mass mortalities among native European crayfish populations. However, several studies have indicated a great variability of pathogen virulence and host resistance, possibly indicating host-pathogen adaptation. This...

Vaarantuneiden jokirapukantojen uhkana on vesistöihimme hyvin sopeutunut vieraslaji, täplärapu, ja sen kantama, erityisesti jokiravuille kohtalokas rapuruton muoto. Rapupopulaatioiden paikantaminen ja seuranta on perinteisesti perustunut paikallistietoon ja koeravustuksiin. Viime vuosien aikana ympäristö-DNA:n (eDNA) käyttöön perustuvat menetelmät...

For 150 years the crayfish plague disease agent Aphanomyces astaci has been the cause of mass mortalities among native European crayfish populations. However, recently several studies have highlighted the great variability of A. astaci virulence and crayfish resistance toward the disease. The main aim of this study was to compare the response of tw...

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. astaci was discovered also in Iberian Peninsula,...

Freshwater crayfish represent keystone species of the freshwater ecosystems. With the introduction of invasive North American crayfish species and their pathogen Aphanomyces astaci a significant decline in the size and abundance of European freshwater crayfish populations was observed. Marbled crayfish is an invasive species exhibiting a high resis...

Abstract Introduction of invasive North American crayfish species and their pathogen Aphanomyces astaci has significantly contributed to the decline of European freshwater crayfish populations. In this study, noble crayfish, a susceptible native European species, and marbled crayfish, an invasive disease-resistant species, were challenged with ha...

Numerous native European freshwater crayfish populations are in decline due to the lethal disease crayfish plague caused by the pathogen Aphanomyces astaci (Oomycetes). Presence of this pathogen has already been recorded in the Plitvice Lakes National Park (NP), Croatia, where two protected native crayfish species, the noble crayfish Astacus astacu...

Eroded swimmeret syndrome (ESS) was first described in 2014 from Swedish signal crayfish (Pacifastacus leniusculus (Dana)), and later also from Finland, with gross symptoms and disease agent candidates identified and described by 2015. The ESS was first discovered affecting alien signal crayfish in Fennoscandia. The ESS is caused by a multiple infe...

Selvitys, tilaustyönä, Terrafamen Talvivaaran kaivoksen Nuasjärven purkuputken kautta johdettavien jätevesien vaikutuksesta Rehja-Nuasjärven veden laatuun ja vesistöalueen mahdolliseen jokirapukantaan. Selvityksessä käsitellään myös mahdollisia vaikutuksia Rehja-Nuasjärven alueelle palautuvaan tai palautettavaan jokirapukantaan sekä lyhyesti vaihto...

Introduction of invasive North American crayfish species and their pathogen Aphanomyces astaci has significantly contributed to the decline of European freshwater crayfish populations. In this study, noble crayfish, a susceptible native European species, and marbled crayfish, an invasive disease-resistant species, were challenged with haplogroup A...

The narrow-clawed crayfish ( Pontastacus leptodactylus ) is an alien species in Finland with only a few populations reported from the southeastern region during the last century. We discovered a productive population in the lake Jängynjärvi, which is upstream from the previously reported wild narrow-clawed crayfish population in that region. Prelim...

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...

Puijon valloitus on ollut savolaisen mielen päällä pitempään kuin Maaningalla on satanut vettä tai pielavetistä on käytetty ratkaisumallina. Puijolle kapuamisen haastetta on pidetty merkillisen suurena, jonka vuoksi Puijon valloitusretki ei todennäköisesti olisi onnistunut ilman ylioppilasta ja hänen oppineita ystäviään. Ylioppilaan kekseliäisyys m...

Crayfish plague, caused by the pathogen Aphanomyces astaci, is one of the main factors responsible for the decimation of the native European crayfish species Austropotamobius pallipes. In Spain, two North American freshwater crayfish species, Procambarus clarkii and Pacifastacus leniusculus, were intentionally introduced during the 1970s for aquacu...

The genus Aphanomyces (Oomycetes) comprises approximately 50 known species of water molds in three lineages. One of the most notorious is Aphanomyces astaci, the causative agent of crayfish plague. In this study, fresh isolates of Aphanomyces were collected from 20 live specimens of the signal crayfish Pacifastacus leniusculus (Dana, 1852) from Lak...

The American rusty crayfish, Faxonius rusticus, is an invasive species in parts of North America where it displaces native crayfish species. In Europe, various invasive North American crayfish species are carriers of the crayfish plague disease agent Aphanomyces astaci that causes devastating population declines of European crayfish. Little is know...

An educational package on crayfish farming, all in Swedish. A movie together with printed material. All availabe in https://www.slu.se/institutioner/akvatiska-resurser/radgivning/kraftor-och-kraftfiske/kraftodlingens-abc/.

Edellisten rapustrategioiden määritelmistä huolimatta täplärapu on jatkanut leviämistään Suomessa. Nyt asiaan ollaan ottamassa aikaisempaa tiukempi ja selkeämpi kanta. Jatkossa täpläravun levittäminen on kielletty.

Global introductions of aquatic species and their associated pathogens are threatening worldwide biodiversity. The introduction of two North American crayfish species, Procam-barus clarkii and Pacifastacus leniusculus, into Japan in 1927 seems to have negatively affected native Japanese crayfish populations of Cambaroides japonicus. Several studies...

Global introductions of aquatic species and their associated pathogens are threatening worldwide biodiversity. The introduction of two North American crayfish species, Procam-barus clarkii and Pacifastacus leniusculus, into Japan in 1927 seems to have negatively affected native Japanese crayfish populations of Cambaroides japonicus. Several studies...

Global introductions of aquatic species and their associated pathogens are threatening worldwide biodiversity. The introduction of two North American crayfish species, Procam-barus clarkii and Pacifastacus leniusculus, into Japan in 1927 seems to have negatively affected native Japanese crayfish populations of Cambaroides japonicus. Several studies...

The oomycete Aphanomyces astaci , the causative agent of crayfish plague, is listed as one of the 100 worst invasive species in the world, destroying the native crayfish populations throughout Eurasia. The aim of this study was to examine the potential of selected mitochondrial (mt) genes to track the diversity of the crayfish plague pathogen A. as...

This study aimed to evaluate the in vitro activity of Zanthoxylum rhoifolium bark (Zr-b) extracts against pathogenic aquatic oomycete/fungal isolates that cause different diseases in native European crayfish resulting in an elevated mortality rate and severe economic repercussions. n-hexane, chloroform, chloroform–methanol (9:1) and methanol extrac...

We present data and results from a 9-year survey (2009 – 2017) of the Lake Saimaa signal crayfish population in Finland. This population has a history of chronic infection with Aphanomyces astaci. It has now been discovered that female signal crayfish from Lake Saimaa suffer from various stages of eroded swimmeret syndrome (ESS), and male crayfish...

We studied the presence of possible Aphanomyces astaci infections in eight Turkish narrow-clawed crayfish (Astacus leptodactylus) populations by analyzing the prevalence and genotypes of the disease agent A. astaci. The qPCR analyses revealed A. astaci infection in seven of the studied eight populations, with the agent level A2 or higher. The agent...

In Finland, massive signal crayfish introductions started towards the end of 1980s, with an estimated total of 2.2 million signal crayfish been stocked before year 2016. During that period, Finnish fisheries authorities have implemented three national management strategies setting guidelines for the crayfish introductions. The main aims of the stra...

Kommentit Mäntyniemen koirakopista, josta kuuluu tyytyväisyys koira-ihminen –suhteen koiran ällistyttävän tarkasta valinnasta. Se pohjustaa tietä toiselle presidenttikaudelle. Vaalikirja, joka tasoittaa presidenttiparin vaiteliaamman osapuolen, koira-ihminen –suhteen koiran, tien jatkoon jo ensimmäisellä kier-roksella. Susi olisi ollut asioiden lai...

Development of post-harvest handling practices of crayfish in Fennoscandia has largely been based on their high value and has historical rationale. Crayfish were transported from Finland to St. Petersburg and Central European markets already in the early mid- 1800s using rather sophisticated methods. Crayfish require cool and moist environment for...

Aphanomyces astaci infection is the cause of crayfish plague in European crayfish. Here the virulence of an A. astaci As strain isolated from apparently healthy stone crayfish (Austropotamobius torrentium) from Slovenia was compared to that of the Psl-Puujärvi A. astaci isolate in 3 crayfish species: noble crayfish (Astacus astacus), signal crayfis...

We conducted a seven-year survey (years 2009 to 2015) of the Lake Saimaa signal crayfish population. Lake Saimaa is the largest single waterbody in Finland, with a productive fishery and crayfishery. The signal crayfish were introduced to Lake Saimaa in mid-1990’s and a commercial fishery was initiated in the mid-2000s. At first, there was a small...

Several North American crayfish species have so far been identified as carriers of the crayfish plague agent Aphanomyces astaci. The pathogen is responsible for the declines of thousands of European crayfish populations. Currently, one of the introduction pathways of North American crayfish species is the aquarium trade which may sometimes be follo...

The genus Aphanomyces (Saprolegniales, Oomycetes) includes species with a variety of ecologies from saprotrophs to plant and animal parasites. Two important species in this genus are A. astaci, the cause of crayfish plague and its close relative, A. invadans, which causes the epizootic ulcerative syndrome on fish. In this study, we have assembled a...

The crayfish plague pathogen, Aphanomyces astaci, is a fungal-like organism (Oomycetes), specialized in parasitizing freshwater crayfish species. Crayfish plague is a disease that has caused losses of indigenous crayfish populations, especially in Europe. The pathogen chronically infects North American endemic crayfish, such as Procambarus clarkii,...

Länsi-Australiassa ravustetaan kuivalla maalla. Sen lisäksi että sikäläiset ravut elävät suuren osa elämästään maan alla, niiden sakset ovat kääntyneet meikäläisittäin kummallisesti ylöspäin.

Publications of the University of Eastern Finland. Reports and Studies in Forestry and Natural Sciences, no 25. 45 p.

For many applications and ecological studies in which wild individuals are brought to laboratory it would be essential to know accurately how fast novel diet is reflected in composition of different tissues. To study the effects of two different diets on the stable isotope composition of freshwater crayfish muscle and hemolymph, we conducted a thre...

The IUCN Red List indexes the noble crayfish (Astacus astacus) as vulnerable, with a declining population trend. The main threats to the species are the crayfish plague caused by the oomycete Aphanomyces astaci and the introduced North American crayfish that act as the carriers of this disease. In Finland, the noble crayfish is considered as a nati...

We describe a novel syndrome in crayfish, eroded swimmeret syndrome (ESS), affecting wild female signal crayfish Pacifastacus leniusculus. ESS causes partial or total swimmeret erosion. We observed ESS only in female signal crayfish larger than 40 mm carapace length, i.e. sexually mature and probably having carried eggs at least once. The eroded sw...

The alien signal crayfish (Pacifastacus leniusculus) was introduced into Finland, and then more broadly in Europe, with the expectation that it would be a suitable substitute for the native crayfish that was eradicated by crayfish plague (Aphanomyces astaci) epidemics. Signal crayfish introductions were promoted and the initial results indicated th...

Aphanomyces astaciis among the most serious pathogens affecting European aquatic ecosystems. We demonstrate that both virulence of A. astaciisolates and resistance of native European crayfish stocks vary notably. Some native European crayfish stocks latently carry crayfish plague, indicating adaptation and contemporary co-evolution between host and...

Emerging diseases, such as the crayfish plague, are a worldwide problem with serious ecological and economic impacts. Under the framework of ecological immunology, we investigated whether variation in crayfish plague resistance, the indicators of immune defence (encapsulation response, phenoloxidase and lytic activity), and the exploration behaviou...