Abstracts

IAA21 Book of Abstracts (PDF)

Meeting Program/Schedule (PDF)

 

 VIEW MEETING PROGRAM ONLINE

 

 

LIST OF MEETING ABSTRACTS

NOTE: You may quickly navigate to a name you are looking for by clicking a letter below (first letter in their lastname).

Oral | Posters

Oral Presentations

 

 

Day: 2, Session: 3, Talk: 2

Crayfish Plague in Spain: Origin and Epidemiology

Laura Martín-Torrijos, Rezinciuc S, Kokko H and Diéguez-Uribeondo J

The aphanomycosis is responsible for the decline of the 5 native species of crayfish in Europe. In the early 1970s, two North American crayfish species, i.e., the signal crayfish, Pacifastacus leniusculus, and the red swamp crayfish, Procambarus clarkii, were introduced into the Iberian Peninsula. Since then, countless cases of the crayfish plague have decimated the native populations of crayfish, Austropotamobius pallipes. In this study, we have analyzed clinical samples from more than 100 cases of aphanomycosis that have occurred in Spain since 1991 until today. We have used sequence analysis to identify the different genetic lineages of A. astaci responsible for the crayfish plague outbreaks in Spain. The results show a direct relationship of crayfish plague outbreaks with the presence of either signal or red swamp crayfish. Thus, in North Spain, where the signal crayfish is more abundant most samples tested positive for the genetic lineages PsI (specific signal crayfish), while in South, Central and Eastern regions where the red swamp crayfish is more abundant, the genetic lineage of A. astaci responsible for the crayfish plague was Pc (specific red swamp crayfish). The results demonstrate once more that these two North American crayfish species are responsible for native crayfish outbreaks in Spain and that their populations represents chronic focuses for spread of the pathogen A. astaci.

 

 

Day: 2, Session: 3, Talk: 4

The Crayfish Plaue Pathogen, Aphanomyces astaci: Pathways, Vectors and Potential Consequences of its Spread in the Introduced Ranges

Agata Mrugala, Kozubíková-Balcarová E, Chucholl C, Kawai T, Kouba A, Svoboda J, Veselý L, Viljamaa-Dirks S and Petrusek A

Introduction of the crayfish plague pathogen, Aphanomyces astaci to Europe is responsable for substantial declines in native European crayfish populations. Although the research on A. astaci dates back to the beginning of the 20th century, knowledge about its introduction pathways, vectors and reservoirs has still many gaps. The presentation will summarize some recent advances in A. astaci research, which resulted from projects undertaken during the first author’s PhD studies. Several North American crayfish species, natural hosts of A. astaci, are used globally for stocking and aquaculture. Therefore, they may pose a threat to endemic crayfish diversity, as happened in Europe. As the first such documented case, we confirmed A. astaci infections in populations of the red swamp crayfish Procambarus clarkii and the signal crayfish Pacifastacus leniusculus in Japan where crayfish plague might have contributed to declines of the endemic crayfish Cambaroides japonicus. Apart from aquaculture, the aquarium trade constitutes a major introduction pathway of crayfish species to and within Europe, and may facilitate A. astaci spread if infected crayfish are released from household aquaria. After screening for pathogen presence in various non-European crayfish species from German ornamental trade, we confirmed that aquarium trade represents a source of A. astaci. Moreover, even ornamental crayfish of non-American origin may contribute to crayfish plague spread, if widely traded species exhibit elevated resistance. We experimentally demonstrated that the Australian yabby Cherax destructor seems indeed less susceptible to A. astaci than European crayfish species, and its release may result in formation of new pathogen reservoirs.

 

 

Day: 2, Session: 4, Talk: 4

Identification of an Austropotamobius pallipes Population with Higher Resistant to the Crayfish Plaque Pathogen, Aphanomyces astaci

Laura Martín-Torrijos and Diéguez-Uribeondo J

The crayfish plague pathogen Aphanomyces astaci is responsible for the decline of the native crayfish species of Europe. This pathogen is believed to be endemic of North America where it seems to have coevolved with its hosts. Thus, North American crayfish species exhibit a high resistance to this pathogen, while species from other regions of the world are highly susceptible. Recent field and laboratory observations appeared to indicate that some populations of the native species, Austropotamobius pallipes, of the Pyreneans might have a higher degree of resistance to A. astaci than others. Consequently, the objective of this study was to test their susceptibility by challenging 8 selected populations with zoospores of an A. astaci strain AP03 isolated from the North American species, Procambarus clarkii. The results show that there are significant differences in susceptibility to crayfish plague (P<0,001) among the selected A. pallipes populations. The majority of the populations showed high mortality rates. However, one population exhibited a 100% survival during the three months monitoring-period. Histological analyses revealed a high immune reaction in tissues examined, e.g., encapsulation and melanization of hyphae, similar to that found in North American resistant species. These results represent to our knowledge, the first observation of native European crayfish showing high resistance towards this pathogen. The identification of this population is of key importance for the management of these endangered species, and represents a crucial step forward towards the elucidation of the factors involved in the immune reaction against this devastating pathogen.

 

 

Day: 3, Session: 1, Talk: 3

The Transcriptome of Noble Crayfish Astacus astacus: An Excellent Tool and a Reference for Further Gene Expression Studies

Theissinger K, Falckenhayn C, Blande D, Toljamo A, Gutekunst J, Makkonen J, Jussila J, Lyko F, Schrimpf A, Schulz R and Hokko H

The native noble crayfish (Astacus astacus Linné, 1758) is one of the keystone species in European freshwater ecosystems, which population trend is currently in decline due to invasive North American crayfish species and the deadly disease, crayfish plague (Aphanomyces astaci), carried and spread by them. We have recently published an annotated transcriptome of the noble crayfish from four combined tissues, including the abdominal muscle, hepatopancreas, ovaries and green glands. A total of 194 million 100 bp read pairs were generated in RNA-seq made on Illumina HiSeq. The transcriptome was assembled de novo using Trinity software, producing 158,649 non-redundant transcripts. Lowly expressed transcripts were filtered out leaving 45,415 transcripts of which 14,559 were containing open reading frames with predicted gene function. Of these, 13,770 transcripts were assigned at least one gene ontology term. The Transrate software realigned 91% of the total reads to the assembly and the BUSCO analysis then indicated the assembly being 64% complete. This first de novo transcriptome assembly is an important foundation for future genomic research on the noble crayfish. The RNAsequencing analysis coupled with functional annotation and relative expression analysis will enable the comprehensive identification of genes that are up- or downregulated for example by different environmental stress factors or diseases.

 

 

Day: 3, Session: 1, Talk: 4

Genomics-informed Development of Molecular Markers for Genotyping the Crayfish Plague Pathogen, Aphanomyces astaci

Diana Minardi, Studholme DJ, van der Giezen M and Oidtmann B

Aphanomyces astaci is an animal parasite and causal agent of crayfish plague, a disease listed by the World Organisation for Animal Health. Aphanomyces spp. are water moulds belonging to the class Oomycota and this genus contains primary pathogens of plants and animals as well as opportunistic and saprotrophic species. Aphanomyces astaci was first introduced into Italy from the U.S. in the late 19^th century and rapidly spread in Europe causing the decline of native crayfish. Random amplified polymorphic DNA PCR (RAPDPCR) on isolates of A. astaci distinguished five genotypes (A, B, C, D and E). No discriminatory morphological or physiological characteristics are available and widely used markers such as ITS, LSU and COI failed to discriminate between genotypes. There are some practical drawbacks to genotyping by RAPD-PCR, not least the requirement for pure cultures. Therefore, we used whole genome sequencing (WGS) on multiple A. astaci isolates to catalogue DNA single nucleotide variants (SNVs) to be exploited as new diagnostic methods, in aid of detection and prevention of crayfish plague. By designing primers surrounding genotype-specific SNVs, amplifying the DNA fragment by PCR and exploiting enzymatic restriction digestion, we were successfully able to distinguish genotypes on pure cultures. This approach was subsequently used on historical crayfish samples available in our laboratories to validate the reliability of this method. Once tested and validated, this method offers a new tool for diagnostics and epidemiological studies aimed at understanding the history and spread of crayfish plague in Europe.

 

Poster Presentations

 

 

POSTER 10

The Impact of Streetlights on an Aquatic Invasive Species: Artificial Light at Night Alters Signal Crayfish Behaviour

Thomas JR, James J, Newman RC, Riley WD, Griffiths SW and Cable J

Artificial light at night (ALAN) can alter the behaviour, communication and orientation of animals, and could interact with other stressors to affect biodiversity. Invasive, non-native species are one of the largest threats to freshwater biodiversity; however, the impact of ALAN on such species is unknown. This study assessed the effects of ALAN at ecologically relevant levels on the behaviour of a globally widespread invasive species, the signal crayfish (Pacifastacus leniusculus). Crayfish were exposed to periods of daylight, control (<0.1 lx) and street-lit nights to test two hypotheses: (1) signal crayfish under natural conditions are nocturnal animals and (2) ALAN reduces the duration of crayfish activity and intraspecific interactions, whilst increasing their propensity to use shelter. Our results confirm that signal crayfish are largely nocturnal, showing peak activity and interaction levels during control nights, whilst taking refuge during daylight hours. However, when exposed to ecologically relevant simulated light pollution from a streetlight at night, activity and interactions with conspecifics were significantly reduced, whilst time spent sheltering increased. Global anthropogenic changes such as ALAN may alter the life history traits and behaviour of invasive species and ultimately influence their impact on invaded ecosystems. The results of the present study suggest that ALAN could reduce the success of signal crayfish in urban areas, by drastically reducing their nocturnal activity. This study is the first to show an impact of ALAN on the behaviour of an invasive, non-native species, and provides information for the management of invasive crayfish in areas where ALAN is prevalent.

 

 

POSTER 12

Analysis of Abundance, Fecundity and Allometric Relationships from Cambarellus montezumae Females During an Annual Cycle

Latournerié-Cervera JR, García-Padilla GM, Estrada-Ortega AR and Arana-Magallón F

Cambarellus montezumae population at Xochimilco, Mexico City, is in serious problems of disappearance. This species was highly appreciated and it was regularly consumed as part of the diet of the Xochimilcas and Mexican people. Nowadays, crayfish is very scarce in this area. As a part of a collaboration research, UNAM and UAM universities have undertaken the project of assessment and rescue of native species in the area of Xochimilco. In this study, we analyze the female population of C. montezumae during an annual cycle. 42 berried females were collected in ten months of sampling (January – October). Abundance varied significantly by sampling month (p<0.05). 76.2% of females were collected during hot rainy season (April – August). Description and analysis of these females were made through: total and cephalothorax length, (TL and CTL). Large and width of abdomen, wet weight, ovigerous mass weight and number of eggs. Minimum, maximum and average values for TL, WW and number of eggs were: (28.31, 43.21, 34.5) mm, (0.58, 1.91, 0.99) g, and 13, 150 and 46.9 eggs respectively. Distributions of TL and WW were positive skewness. Allometric relationships were calculated for WW – TL (potential model, r²=0.93), CTL – TL (linear model, r²=0.86). Fecundity – TL was positive correlated (r=0.68, p<0.05). Also positive and significant correlations (p<0.05), were obtained for abdomen width and length – TL and female abundance – temperature. Ovigerous mass weight was higher on April and number of eggs per female was bigger on September. We discuss results in relation to scarcity of berried females, the decrease in the number of eggs per female, the size of first maturity, and anthropogenic impacts in the study area.

 

 

POSTER 14

Detection of Invasive Crayfish Populations by Environmental DNA in Fishponds from the Natural Park of Brenne

Mauvisseau Q, Coignet A, Delaunay C, Pinet F, Bouchon D and Souty-Grosset C

Environmental DNA (eDNA) is a powerful method for assessing the presence and the distribution of invasive aquatic species. We used this tool in order to detect and monitor several invasive crayfishes Procambarus clarkii, Orconectes limosus and Pacifastacus leniusculus,/i> present or likely to invade the fishponds of the Natural Regional Park of Brenne, one of the most important wetland in France and listed as an International RAMSAR wetland zone since 1991 We designed specific primers for each crayfish species, and set up an experimental aquarium approach to confirm the specificity of the primers and the sampling protocol. We analysed samples taken in the Natural Regional Park of Brenne in 2014 and 2015. The field experiment has proven the reliability of the eDNA detection method. Both experiments confirm that qPCR using SybrGreen protocol with the same primers give better reliable results that with TaqMan protocol. After optimization of the eDNA detection in water samples, it is concluded that sampling must be made during the main period of activity of crayfish, i.e. in summer. This method is a powerful tool for establishing the presence or absence of invasive species in the numerous ponds (more than 2000) in the National Regional Park of Brenne.

 

 

POSTER 15

Reproductive Cycle of the Marble Crayfish from an Established Population in Croatia

Cvitanić M, Hudina S and Maguire I

The marble crayfish (Procambarus fallax f. virginalis) is a relatively new non-indigenous crayfish species that has established populations in Europe. Until today, it is the only known decapod species with parthenogenetic reproduction. Established population of marble crayfish was recently discovered in a gravel pit in Northwest Croatia. Apart from parthenogenetic reproduction, the invasion success of this species stems from its early maturation, and higher fecundity compared to other crayfish species. Therefore, the aim of this study was to examine the year cycle of the marble crayfish in Croatia, and its potential (number of ovarian eggs) and realized fecundity (number of pleopodal eggs and juveniles). Our results show that all 140 examined individuals were reproductively active during the whole sampling period. Peaks of reproduction activity were recorded from September to November, when both individuals with pleopodal eggs or juveniles as well as individuals with ripe ovarian eggs were recorded. The smallest reproductively active female was 40.81 mm TL, while reproductive output increased with size (TL). The average number of ovarian eggs was 297. The average number of pleopodal eggs was 15% lower than the number of ovarian eggs, while number of juveniles attached to pleopods was reduced by 50% from ovarian egg count. This represents a lower brood loss compared to other crayfish species. Due to almost constant reproduction, early maturation and relatively high potential and realized fecundity in an established population in Croatia, the marble crayfish represents a major threat to the surrounding waterbodies and their native crayfish fauna.

 

 

POSTER 28

Management of the Native White-clawed Crayfish, Austropotamobius pallipes, in the Province of Girona

Montserrat J, Macias M and Torres F

The native white-clawed crayfish (Austropotamobius pallipes) was a species commonly found in most watercourses in the basins of the rivers Fluvià, Ter and Muga until the end of the 1970s, when the crayfish plague Aphanomyces astaci arrived, a water mould that led to the disappearance of almost all the populations in these river basins. The white-clawed crayfish populations are currently found in second-order or larger seasonal rivers and fast-flowing streams where, due to some kind of natural barrier (drought in the lower reaches of the watercourse, cliffs, etc.), the fungus was unable to grow. Moreover, during the 1990s, the red swamp crayfish (Procambarus clarkii) population expanded rapidly in the basin and the situation became far worse, since the North American species is both a carrier of the crayfish plague and resistant to this fungal disease. Later, the signal crayfish (Pacifastacus leniusculus) arrived in the Ter River and the spinycheek crayfish (Orconectes limosus) arrived in the Muga River Basin, both species being carriers of the pathogen Aphanomyces astaci. This situation means relict populations of the white-clawed crayfish cannot expand and are forced to survive in the most inaccessible seasonal rivers and fast-flowing streams, facing the danger of a new outbreak of crayfish plague.