Abstracts

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LIST OF MEETING ABSTRACTS

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Oral | Posters

Oral Presentations

 

 

Day: 2, Session: 4, Talk: 3

A Survey of Various Wild Crayfish Populations in Germany and Austria Reveals New Insights into the Spread and Diversity of Aphanomyces astaci

Jörn Panteleit, Keller NS, Jussila J, Kokko H, Makkonen J, Schulz R, Theissinger K and Schrimpf A

The crayfish plague agent, Aphanomyces astaci, is one of the main causes for the numerous losses of native European crayfish populations due to mass mortalities caused by the disease agent throughout Europe. Different genetic lineages of A. astaci have been introduced to Europe independently with repeated introductions of different American non-indigenous crayfish species (NICS). Some of these lineages have shown to be more detrimental to the indigenous crayfish species (ICS) than others. We studied crayfish from 26 locations (in total 427 samples) in Germany and Austria for possible A. astaci infection using quantitative real- time PCR. Additionally, we used microsatellite and sequence analysis to identify the different genetic lineages of A. astaci. We could identify A. astaci infections in 15 crayfish populations (a total of 26% of samples were showing A. astaci DNA). Aphanomyces astaci lineages of seven populations were also identified. In particular, three findings are of special interest: (i) the Up lineage, a recently discovered novel variant by Grandjean et al. (2014), was present in at least two crayfish populations in Austria. (ii) A population of stone crayfish (Austropotamobius torrentium) in Austria was infected by two genetic lineages of A. astaci (PsI and Up lineages), and (iii) the Pc lineage revealed mutations in the mitochondrial LSU- gene in a population of A. torrentium that lives in a stream which also contains a population of signal crayfish (Pacifastacus leniusculus). Our study provides insights into the current situation and diversity of A. astaci in the studied area.

 

 

Day: 5, Session: 1, Talk: 3

Polyphenols as Feed Additives: A New Tool to Prevent Diseases in Farmed Crayfish?

Marina Paolucci, Parrillo L, Scioscia E, Coccia E, Siano F, Pagliarulo C, Voloe MG, Jussila J, Makkonen J and Varricchio E

Polyphenols are a large class of chemical compounds with antioxidant properties, derived from plants. Epidemiological, clinical and nutritional studies strongly support the evidence that dietary phenolic compounds enhance human health by lowering the risk of most common degenerative and chronic diseases that are known to be caused by oxidative stress. Although some polyphenols are employed as feed additives to reduce free radicals and therefore to improve the oxidative stability and quality of the meat, their application in animal nutrition is a field largely unexplored. In this study, we present some encouraging preliminary data on the effects of polyphenols extracted from two agricultural wastes (olive mill waste water, chestnut skin) and from three different types of honey (chestnut, acacia and clover) tested in vitro against two pathogenic aquatic fungal isolates, Aphanomyces astaci and Fusarium avenaceum, that cause different diseases in native European crayfish, with a high mortality rate and severe economic repercussions. Moreover, olive mill waste water (OMWW) was tested in a long term feeding trial on the crayfish Astacus leptodactylus. Our results show in vitro inhibitory effects, of agricultural waste extracts on Aphanomyces astaci and Fusarium avenaceum. In vivo, OMWW enriched diets improved parameters of growth performance, feed utilization, survival and nutritional status, as well as immunological parameters (phenoloxidase activity, superoxide anion production) in crayfish. These results, although preliminary, encourage to promote their use in the prevention and treatment of fungal diseases. Our next step would be to test the efficacy of polyphenols on crayfish challenged with pathogens.

 

 

Day: 5, Session: 3, Talk: 5

Conserving White-clawed crayfish Austropotamobius pallipes in an Upland Catchment in Yorkshire, A Case Study

Stephanie Peay

White-clawed crayfish were abundant throughout the catchment of the River Ribble in northwest England until an outbreak of crayfish plague caused the loss of the population in most of the catchment. Some relict fragments of population survived in semi-isolated areas and show signs of recovering. Restocking was carried out successfully in one tributary and another stocking carried out to establish an ‘ark site’ population in an isolated part of the catchment. The reintroduced population expanded to approximately 4 km range in six years, with an expanding peak abundance detected by trapping four years after stocking. In another tributary initial stocking too high up in the headwaters was unsuccessful and necessitated restocking further downstream in a stretch with lower gradient and more flow. Future constraints and opportunities are discussed.

 

 

Day: 5, Session: 4, Talk: 1

The Future of Endangered Austropotamobius torrentium (Schrank 1803) in the Light of Protected Areas and Habitat Fragmentation: A Case Study from the Carpathians

Lucian Pârvulescu, Iorgu EI, Satmari A, Zaharia C, Drǎguț L, Krapal AM, Popa OP and Popa LO

Fragmentation is one of the most challenging issues in conservation ecology. The aim of this work fits within the goal to find reliable methods for its assessment in freshwater habitats through a case study on the endangered stone crayfish, Austropotamobius torrentium (Schrank 1803). We focused on 17 populations in the Danube basin, from which 297 individuals were sampled and genotyped. Genetic variation and genetic structure were analysed based on 5 polymorphic DNA microsatellite loci. By following rivers linearity, the connectivity between the populations was assessed by determining the geographical distance. Next, based on ecological data from the known populations in Romanian Carpathians, we built an ecological model in order to find the most suitable predictors describing the species distribution. We developed a Random Forest model with catchment CORINE land-cover (as a surrogate for habitat quality), slope, altitude and mean multiannual temperature as predictors. We used this model to predict the species occurrence to the entire river network connecting the target populations, thus obtaining a third type of distance, an ecological one. Only one population showed significant deviation from Hardy-Weinberg equilibrium. Genetic variation, expressed by mean expected heterozygosity (HE) ranged between 0.422 and 0.752. AMOVA analyses show that the diversity between populations corresponds to 44% of total variability. High levels of genetic differentiation among populations were confirmed by high average FST and RST values (0.2896 and 0.4856 respectively). We found the best explanation of the inadvertences between molecular and geographical distances was provided by the ecological component, thus highlighting the importance of ecological approaches in the assessment of fragmentation. This case study points out a practical method for the assessment of ecological fragmentation, and also suggests that the communication pathways for freshwater organisms are of high importance for the preservation of diversity in populations.

 

Poster Presentations

 

 

POSTER 2

Crayfish Epibionts Branchiobdella sp. on the Stone Crayfish in the Czech Republic

Vlach P and ŠrámkováL

This contribution evaluates the occurrence of crayfish epibionts Branchiobdella inhabiting stone crayfish in the Czech Republic. The study was conducted in 8 localities (from app. 40 known localities), respecting its natural range in the country. In total, we determined 723 individuals of 4 species: Brynchiobdella pentodonta,/i>, B. hexodonta, B. parasita and B. astaci. B. pentodonta dominated (403 ind.) in the whole sample, and also B. parasite,/i> occurred frequently (316 ind.). On the other hand, B. hexodonta was recorded only three times and B. astaci only once in the left tributary of Novosedlský brook in Upper Palatine Forest. The most variable locality was Huníkovský brook with 3 recorded Branchiobdella species - B. parasita, B. pentodonta and B. hexodonta, whose occurrence was recorded only in this stream. B. parasita was mostly the dominant species, or occurred equally to B. pentodonta in the stream Chýlava. On the contrary, in Zubrina, the abundance of B. pentodonta prevailed. The highest abundance of Branchiobdella sp. was recorded in Zubrina (17 ind. per one crayfish on average), conversely the lowest number in Medvedí brook was observed (0.3 ind. per crayfish). Moreover, we found out that B. pentodonta significantly preferred its position on crayfish chelae, whereas B. parasita inhabited the whole crayfish body equally, except for chelae. The last findings could correspond with interspecific competition between both species.

 

 

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 17

North American Branchiobdellida (Annelida: Clitellata) or Crayfish Worms in France: The Greatest Diversity of These Alien Ectosymbionts in Europe

Parpet JF and Gelder SR

Over the last five years, biomonitoring of freshwater bodies resulted in alien crayfishes being collected from the Garonne, Loire, Seine and Rhône basins in France. These crayfishes (Pacifastacus leniusculus (Dana, 1852), Procambarus clarkii (Girard, 1952), Orconectes limosus (Rafinesque, 1817)) from North America also carried ectosymbionts of the order Branchiobdellida (Annelida, Clitellata) or crayfish worms. Initially we reported (Gelder et al., 2012) the distribution in France of Xironogiton victoriensis Gelder and Hall, 1990, Cambarincola gracilis Robinson, 1954 and Cambarincola okadai Yamaguchi, 1933 on the signal crayfish, P. leniusculus, indigenous to the Pacific Northwest of North America; additional information is included here. Signal crayfish found in the Seine basin also carried Triannulata magna Goodnight, 1940, and this is the first record of this species in Europe. Louisiana red swamp crayfish, Pr. clarkii, were collected in the Adour basin along with their endemic, Cambarincola mesochoreus Hoffman, 1963. This is the first report of both host and branchiobdellidan in France. A unique host/branchiobdellidan combination was discovered when western North American X. victoriensis was observed on eastern North American spiny cheek crayfish, Orconectes limosus (Rafinesque, 1817). Although France has the most reported alien branchiobdellidan species in Europe, a number of other countries also have established North American branchiobdellidan populations. The impact of these alien species on the endemic Branchiobdella spp. is unknown, but warrants concern and further study, besides investigating their impact on other invertebrates in the freshwater ecosystem.

 

 

POSTER 20

Novel Microsporidian Infection in the Japanese Endemic Crayfish Cambaroides japonicus

Pretto T, Tanaka, Diéguez-Uribeondo J and Kawai T

The endemic crayfish, Cambaroides japonicus (de Haan, 1841) is the only native crayfish species in Japan. The rapid decreasing of its native range, which comprises Hokkaido and the Northern Honshu, led the Environmental Agency in Japan to consider C. japonicus as an endangered species. During a monitoring survey on the distribution of C. japonicus,/i> in Hokkaido in 2011, a specimen with atypical whitish appearance of the abdominal musculature were observed in Lake Toyoni and porcelain disease (Thelohania sp.) has been suspected. A focused survey conducted in Lake Toyoni in 2013 revealed the presence of macroscopically affected crayfish with a prevalence of 6.3%. Ethanol fixed C. japonicus were analyzed and muscle samples for molecular analysis were taken from 8 affected specimens. The small subunit ribosomal DNA (SSU rDNA), amplified with generic microsporidian primers (Weiss and Vossbrinck, 1998), was sequenced and compared with other marine, freshwater and terrestrial Microsporidia. Histological analysis of the abdomen revealed high densities of ovoid single spores, not contained inside a sporophorous vescicle, in striated muscle cells of the pleonal extensor and flexor muscles. No spores were recorded in the intestinal musculature nor in the ventral ganglia. The affected muscle fibers were frequently surrounded by haemocytic infiltration and sporadic melanization. The phylogenetic analysis of the SSU rDNA placed this undescribed microsporidium between members of the class Marinosporidia (Vossbrinck and Debrunner-Vossbrinck, 2005), distant from the microsporidia of other European and Australian crayfish. Further studies are needed to describe the developmental stages and the ultrastructural features of this microsporidium.

 

 

POSTER 27

Eradicating Signal Crayfish with a Biocide: What Worked, What Didn’t

Peay S

In its introduced range in Europe signal crayfish Pacifastacus leniusculus has become invasive, with impacts on indigenous crayfish and other fauna. Where a new population is detected while it is still localised there is the potential to carry out a biocide treatment to try to eradicate the population. During 2004 to 2012 six treatments with natural pyrethrum have been carried out in Scotland and England, followed by intensive monitoring for five years to determine outcome. Results show there were two confirmed successes and one probable (after three years monitoring, ongoing) and three sites where complete eradication was not achieved. Treatments and relevant factors are outlined and key lessons learned.