22 June 2016

Chucholl, 2016b

Chucholl C. 2016b. The bad and the super-bad: prioritising the threat of six invasive alien to three imperilled native crayfishes. Biological Invasions 18(7): 1967-1988. http://dx.doi.org/10.1007/s10530-016-1141-2

Abstract

Multiple species invasions and limited resources for management require prioritisation of deleterious effects of invaders on imperilled native species. This study prioritises the threat of six non-indigenous crayfish species (NICS) to three indigenous crayfish species (ICS) in southwestern Germany, a European region with high diversity of crayfish species and freshwater habitats. Using multivariate statistical analyses and niche-based species distribution models, the (1) contemporary and potential range overlap, (2) habitat overlap, and (3) rate of spread of the nine species were assessed. Predicted and contemporary range overlap with ICS was consistently the highest for the alien signal crayfish. Environmental niches of ICS tended to be associated with cooler temperatures (except for white-clawed crayfish), lower Human Influence Index, and higher terrain slope than that of alien Orconectes and Procambarus species, but were mostly similar to that of signal crayfish. Habitat overlap was found to be the highest between signal crayfish and ICS. In contrast to Orconectes and Procambarus species, signal crayfish also invade headwaters, where the most ICS populations occur. Range expansion during the past 15 years was the highest for signal crayfish, followed by Orconectes species. Because of the great potential to invade as-yet isolated refuge areas and spread at a high rate, signal crayfish is of the highest concern for conservation of ICS and should be primarily targeted by prevention and control measures. However, it merely represents the ‘worst of the worst’, since all NICS of North American origin are natural reservoirs of crayfish plague, a fatal disease of ICS.

Keywords: aquatic invaders • risk assessment • Crustacea • distribution models • habitat association

Lipták and colleagues, 2016

Lipták B, Mrugala A, Pekárik L, Mutkovic A, Grula D, Petrusek A, Kouba A. 2016. Expansion of the marbled crayfish in Slovakia: beginning of an invasion in the Danube catchment? Journal of Limnology 75(2): 305-312. http://dx.doi.org/10.4081/jlimnol.2016.1313

Abstract

The marbled crayfish, Procambarus fallax f. virginalis, is a taxon widely available in the aquarium pet trade, which has been introduced to open waters in several European countries and in Madagascar. Recent studies confirmed this parthenogenetically reproducing crayfish as a high-risk invasive species, and vector of the crayfish plague pathogen, Aphanomyces astaci. It has been first discovered in Slovakia in 2010, but the status of the local population was not studied since then. Due to enlarged sampling area around the first report and one locality, where we presupposed the crayfish occurrence, we identified new marbled crayfish populations. Here, we report presence of three newly established marbled crayfish populations in Slovakia. Two populations are located critically close to the Váh River, a major tributary of the Danube River; one of them being directly connected to the Váh River via a side channel during occasional floods. The third established marbled crayfish population was found at the mouth of a thermal stream flowing into the Nitra River, a tributary of the Váh River. In this stream, crayfish coexist with other exotic fish and gastropod species of aquarium origin. We presume that the reported localities may serve as a source for further expansion of the marbled crayfish in the mid-part of the Danube catchment. Floods, active dispersal (including overland), passive dispersal by zoochory or anthropogenic translocations are among the major drivers facilitating the marbled crayfish colonization. We have not detected the crayfish plague pathogen in any of the studied populations. However, if spreading further, the marbled crayfish will encounter established populations of crayfish plague carriers in the Danube River, in which case they may acquire the pathogen by horizontal transmission and contribute to spread of this disease to indigenous European crayfish species.

Keywords: aquarium pet trade • crayfish plague • freshwater crayfish • Procambarus fallax f. virginalis • species introductions

11 June 2016

Chatila, 2016

Chatila Z. 2016. Lentiviral GFP transfection of the parthenogenic crayfish species, Procambarus fallax: a tool for examining the source of neural precursor cells in crayfish. Undergraduate honors thesis, Neuroscience, Wellesley College. http://repository.wellesley.edu/thesiscollection/345/

Abstract

The thesis is embargoed online until 22 April 2018. I am attempting to get a copy of the abstract to place here earlier than that.

31 May 2016

Kouba and colleagues, 2016

Kouba A, Tíkal J, Císar P, Veselý L, Fort M, Príborský J, Patoka J, Buric M. 2016. The significance of droughts for hyporheic dwellers: evidence from freshwater crayfish. Scientific Reports 6: 26569. http://dx.doi.org/10.1038/srep26569

Abstract

Freshwater biodiversity is globally threatened by various factors while severe weather events like long-term droughts may be substantially devastating. In order to remain in contact with the water or stay in a sufficiently humid environment at drying localities, the ability to withstand desiccation by dwelling in the hyporheic zone, particularly through vertical burrowing is crucial. We assessed the ability of three European native and five non-native crayfish as models to survive and construct vertical burrows in a humid sandy-clayey substrate under a simulated one-week drought. Three native species (Astacus astacus, A. leptodactylus, and Austropotamobius torrentium) suffered extensive mortalities. Survival of non-native species was substantially higher while all specimens of Cherax destructor and Procambarus clarkii survived. The native species and Pacifastacus leniusculus exhibited no ability to construct vertical burrows. Procambarus fallax f. virginalis and P. clarkii constructed bigger and deeper burrows than C. destructor and Orconectes limosus. In the context of predicted weather fluctuations, the ability to withstand desiccation through constructing vertical burrows into the hyporheic zone under drought conditions might play a significant role in the success of particular crayfish species, as well as a wide range of further hyporheic-dwelling aquatic organisms in general.

Keywords: behavioural ecology • biodiversity • hydrology • limnology


03 May 2016

Lőkkös and colleagues, 2016

Lőkkös A, Müller T, Kovács K, Várkonyi L, Specziár A, Martin P. 2016. The alien, parthenogenetic marbled crayfish (Decapoda: Cambaridae) is entering Kis-Balaton (Hungary), one of Europe’s most important wetland biotopes. Knowledge and Management of Aquatic Ecosystems 417: 16. http://dx.doi.org/10.1051/kmae/2016003

Abstract 

The marbled crayfish or Marmorkrebs, Procambarus fallax (Hagen, 1870) f. virginalis, a parthenogenetic freshwater crayfish belonging to the North American cambarids, was recorded in Hungary for the first time. Several specimens of this potentially invasive crayfish were caught at different locations in the thermal Lake Hévíz and its outflows in the western part of the country. Captured individuals covered a wide size range (5.5 to 50.5 mm carapace length) and one was carrying eggs and recently hatched offspring, which suggests that this organism has established a stable and self-sustaining population in the warm habitats of Lake Hévíz area. This finding is of great significance because these habitats belong to the catchment of the Danube River including Lake Balaton, and thus, a significant further spread of the marbled crayfish is likely to happen in Central Europe. Furthermore, the expansion of this crayfish already reached the Kis-Balaton, one of the landscape protection areas of the Balaton Uplands National Park, what could have currently yet unpredictable consequences for this unique wetland biotope.

Keywords: non-indigenous crayfish species • pet trade • illegal release • crayfish plague • thermal lake

Note: One of the latitude and longitude coordinates in Table 2 is incorrect. The coordinates for Lake Hévíz should be N 46° 47.252', E 17° 11.501'. The corresponding author confirmed this.

02 May 2016

African crayfish


The Conversation hosts a good post by Ana Nunes about the introduction of crayfish into Africa. Marmorkrebs make a brief cameo appearance (with an incomplete name):

Another species that bears mentioning is the marbled crayfish or “Marmokrebs” (Procambarus fallax) (sic). It was introduced to Madagascar for mysterious reasons, but there may be a link with a road building project carried out by foreign contractors in 2003/2004. In 2005, biologists at the University of Antananarivo noticed it being sold in markets close to the capital.

This particular crayfish has a peculiar history: nobody knows where it comes from. It simply appeared in the German aquarium trade in about 1995. It is also the only decapod in the world known to be able to reproduce by parthenogenesis – a female is able to reproduce without being fertilised by a male. This means that a single individual is sufficient to start a whole new population. As such, this species seems very likely to pose a serious threat to freshwater biodiversity in Madagascar.

Even though it focuses on one continent, it is a very nice lay summary of the issues around crayfish introductions.

External links

Freshwater crayfish: the forgotten invaders wreaking havoc across Africa

Pictured: Lake Naivasha, site of a Procambarus clarkii introduction. Picture from here.

19 April 2016

Korša, 2016

Korša A. 2016. Epifauna on freshwater crayfish (Crustacea: Decapoda) in Croatia. Master's thesis, Department of Biology, University of Zagreb.http://digre.pmf.unizg.hr/id/eprint/4635

Abstract

The research of epifauna on freshwater crayfish as basibionts was conducted during springsummer (sic) 2014. and 2015. Epizoic community was examined from five different crayfish: three autochtonous species Astacus astacus, Austropotamobius pallipes, A. torrentium and two introduced, invasive species Pacifastacus leniusculus and Procambarus fallax f. viriginalis. The aims of this research were: (i) to analyze epizoic community living on freshwater crayfish, (ii) to compare epifauna living on crayfish with surrounding fauna living on sediment and periphyton, (iii) to compare epifauna between crayfish species, especially between autochthonous and allochthonous species. The results of statistical analysis indicated a significant difference between epifauna and fauna of sediment and periphyton. 44 different taxa of epifauna was recorded. The most abundant group was Ciliophora with most common species Vorticella campanula and Epistylis sp. The most diverse group was Rotifera with most common species Lepadella parasitica and Dicranophorus hauerianus. Branchiobdellidanas were confiremd (sic) as common crayfish epibionts and for the first time nort (sic) american species Xirogiton victoriensis has been recored (sic) in Croatia. Catenulida, Gastrotricha, Nematoda, Bivalvia, Hirudinea, Tardigrada, Crustacea, Hydrachnidia and Chironomidae were also recorded living on freshwater crayfish. Results of NMDS and Cluster analyses showed the eparation (sic) of epifauna from autochotnous and allochthonous crayfish and also the separation of epifauna between autochthonous species. Results of statistical analyses showed significant difference between epifauna and fauna of sediment and periphyton. It can be concluded that the whole epizoic community composition established on a particular crayfish is species-specific and can be different between basibiont species.

Keywords: autochtonous and alochtonous species • epibionts • basibionts • Ciliophora • Rotifera • Xirogiton victoriensis