Moog and colleagues, 2019

Moog O, Leitner P, Huber T, W. R, Graf W. 2019. Marbled Crayfish (Procambarus virginalis Lykow, (sic) 2017) – a supplement to the list of Aquatic Invertebrate Neozoa in Austria. ECOPROF. https://www.ecoprof.at/index.php/faunaaquaticaaustriaca.html?file=files/ep_downloads/faa/New_Neozoon_Marbled%20Crayfish.pdf

Abstract

The marbled crayfish (Procambarus virginalis Lykow (sic), 2017) is added to the list of aquatic invertebrate neozoa in Austria. The scientifically proven first evidence of marbled crayfish in Austria took place in June 2018 and was published by Latzer & Pekny (2018). The occurrence of the marbled crayfish is so far known only from two ponds in Salzburg (Karlsbader Weiher and pond FBZ I/135; Latzer & Pekny, 2018) and one finding in Vienna. According to Thomas Ofenböck (Municipal Department 45 - Water Management), in August 2018 a single specimen was found in the 22nd district and released in the Mühlwasser. The Mühlwasser is a former branch of the Danube at Stadlau (Vienna, 22. District); since 1875, there is no connection to the river anymore. Although the establishment status of the marble crayfish is unknown, there are two reasons for its inclusion in the list of Austrian aquatic neozoa. 1) the management of the Salzburg state fishing association (Salzburger Landesfischereiverband) must assume that the population cannot be eradicated (personal communication Mrs. Daniela Latzer, Salzburg); 2) an establishment (in the sense of permanent, reproducing populations) is to be assumed since the species reproduces parthenogenetically.

Keywords: None provided.

Latzer and Pekny, 2018

Latzer D, Pekny R. 2018. Erstnachweis des Marmorkrebses für Österreich in Salzburg. Salzburgs Fischerei 49(3): 24-30. https://issuu.com/lfvs/docs/safisch_3-18

Abstract

Der landesfremde Marmorkrebs wurde nun erstmals in Österreich, und zwar in Salzburg gefunden: dieser Krebs ist auch als sog. „Klon-Krebs" bekannt. Es kommen nur weibliche Tiere vor, die sich parthenogenetisch, also per Jungfernzeugung, fortpflanzen.

Keywords: None provided.

Approximate English translation of abstract:

The foreign marbled crayfish was now in Austria for the first time, specifically found in Salzburg: this crayfish is also known as the “clone crayfish.” Only females come from these animals, which reproduce parthenogenetically, i.e. by means of virgin generation.

Szendőfi and colleagues, 2018

Szendőfi B, Bérces S, Csányi B, Gábris V, Gál B, Gönye Z, Répás E, Seprős R, B. T, Kouba A, Patoka J, Weiperth A. 2018. Egzotikus halfajok és decapodák a Barát‐ és Dera‐patakban, valamint a torkolatuk dunai élőhelyein. Pisces Hungarici 12: 47-51. http://www.haltanitarsasag.hu/ph12/Szendofi_et.al_Pisces.Hungarici_2018.pdf

(English title: Occurrence of exotic fish and crayfish species in Barát and Dera
creeks and their adjacent section of the River Danube)

Abstract

Thermal and urban waters are frequently subjected to the releases of aquatic pets, which often occur in unexpected assemblages of native and non‐native species. To document this, we conducted a half‐year‐long (January – July 2018) field survey the crayfish and fish species present in Barát and Dera creeks (two sampling sites per each) and sections adjacent to their mouth in the River Danube. Sampling sites were inspected monthly using a combination of catching methods. Altogether, four non‐native crayfish, ten nonnative and twelve native fish were recoded. Several individuals of spiny‐cheek crayfish (Faxonius limosus), marbled crayfish (Procambarus virginalis), red swamp crayfish (Procambarus clarkii) and Australian redclaw (Cherax quadricarinatus) were sampled in the thermal water tributary of Barát creek. The Dera creek was not influenced with the thermal or industrial warm water, but the urbanised area affected the water quality, which was still acceptable for occurrence of spiny‐cheek crayfish, marbled crayfish and red swamp crayfish. Besides already well established population of spiny‐cheek crayfish, also marbled crayfish and red swamp crayfish inhabited the River Danube itself. Seven non‐native decapods have been reported in the Hungarian wild so far. However, this is to our knowledge the first published report on co‐occurrence of three North‐American crayfish as well as a combination of North‐American and Australasian crayfish species in Europe. The new faunistic records of exotic live‐bearing fish species from the family Poeciliidae and their hybrids from Barát creek were also obtained. These findings highlight the significance of pet trade as an introduction pathway and thermal as well as urban waters as target sites for new introductions. Roles of established nonnative species and their possible spread are issues requiring further targeted research.

Keywords: biological invasion • thermal water • tributary • Danube

Link roundup for June 2020

Friend of the blogGünter Vogt has a write-up for non-specialists about Marmorkrebs at the Atlas of Science.

• • • • •

Great Lakes Now has a story about the efforts to keep invasive species out of the Great Lakes. It starts with Marmorkrebs being banned in Michigan, saying that the new policy made headlines. Other crayfish are discussed more in the article, mostly Louisiana red swamp crayfish.

Rusch and colleagues, 2020

Rusch JC, Mojžišová M, Strand DA, Svobodová J, Vrålstad T, Petrusek A. 2020. Simultaneous detection of native and invasive crayfish and Aphanomyces astaci from environmental DNA samples in a wide range of habitats in Central Europe. NeoBiota 58: 1-32. https://doi.org/10.3897/neobiota.58.49358

Abstract

Crayfish of North American origin are amongst the most prominent high-impact invasive invertebrates in European freshwaters. They contribute to the decline of European native crayfish species by spreading the pathogen causing crayfish plague, the oomycete Aphanomyces astaci. In this study we validated the specificity of four quantitative PCR (qPCR) assays, either published or newly developed, usable for environmental DNA (eDNA) screening for widely distributed native and non-native crayfish present in Central Europe: Astacus astacus, Pacifastacus leniusculus, Faxonius limosus and Procambarus virginalis. We then conducted an eDNA monitoring survey of these crayfish as well as the crayfish plague pathogen in a wide variety of habitat types representative for Central and Western Europe. The specificity of qPCR assays was validated against an extensive collection of crayfish DNA isolates, containing most crayfish species documented from European waters. The three assays developed in this study were sufficiently species-specific, but the published assay for F. limosus displayed a weak cross-reaction with multiple other crayfish species of the family Cambaridae. In the field study, we infrequently detected eDNA of A. astaci together with the three non-native crayfish species under examination. We never detected eDNA from A. astaci together with native crayfish, but in a few locations eDNA from both native and non-native crayfish was captured, due either to passive transport of eDNA from upstream populations or co-existence in the absence of infected crayfish carriers of A. astaci. In the study, we evaluated a robust, easy-to-use and low-cost version of the eDNA sampling equipment, based mostly on items readily available in garden stores and hobby markets, for filtering relatively large (~5 l) water samples. It performed just as well as the far more expensive equipment industrially designed for eDNA water sampling, thus opening the possibility of collecting suitable eDNA samples to a wide range of stakeholders. Overall, our study confirms that eDNA-based screening for crayfish and their associated pathogen is a feasible alternative to traditional monitoring.

Keywords: crayfish plague • eDNA monitoring • eDNA sampling methods • quantitative PCR • TaqMan assay validation

Bans on Marmorkrebs could hurt research

If you want to talk about a success story in invasive species management, you might want to talk about the province of Alberta, Canada. Alberta like to boast that it is rat free.

But I can let you in on a little secret. I’ve seen rats in Alberta many times, when I was a student at the University of Lethbridge. Last year, the university got a government grant to build a new rat facility.

So there was a disconnect between declaring “We don’t want this invasive species!” and actually having that species in research labs. The two situations are separable.

I am not sure if that separation will exist for Marmorkrebs, though.

This year, Saskatchewan and Michigan banned Marmorkrebs. Ontario and some other US states are thinking about it.  I have been thinking about what the bans might do for Marmorkrebs research. There are several issues.

First, researchers in those states and provinces might not be able to have Marmorkrebs at all. Some of the Marmorkrebs legislation does not appear to have exceptions for bona fide academic researchers.

For example, the Canadian province of Manitoba has a law against owning all crayfish species, not just Marmorkrebs. In the course of doing research, I once asked officials in Manitoba if a researcher might keep crayfish, and was told, “No.”

Second, if the laws work as intended, fewer people in general would have Marmorkrebs. It’s possible that some pet owners would stop keeping Marmorkrebs, even in jurisdictions where it is completely legal. Aquarium keepers might see “the writing on the wall” and decide not to keep Marmorkrebs any more, in case they become illegal.

This could affect researchers, too. When an animal is widely available in the pet trade, it’s easy for researchers to get them, either for a one-off study or to start a colony.

Crayfish researchers have a long history of asking for regulation of the movement and trade of crayfish. It has been hard to get those regulations, but it would be a shame if new laws were not nuanced enough to allow original research.

If there can be rats in labs in Alberta, we should be able to have crayfish in labs, too. After all, an escaped crayfish in a university building probably has a harder time getting far than an escaped rat would. 

External links

Extinction agenda: How border patrols enforce a uniquely rat-free Alberta

Poster from here.

Velisek and colleagues 2020b

Velisek J, Stara A, Zuskova E, Chabera J, Kubec J, Buric M, Kouba A. 2020. Effects of chloridazon on early life stages of marbled crayfish. Chemosphere 257: 127189. https://doi.org/10.1016/j.chemosphere.2020.127189

Abstract

The effects of chloridazon exposure at concentrations of 2.7 μg/L (maximal real environmental concentration in the Czech Republic), 27 μg/L, 135 μg/L and 270 μg/L on early life stages of marbled crayfish (Procambarus virginalis) were evaluated. Significantly higher glutathione S-transferase activity and reduced glutathione level was observed at all tested concentrations of chloridazon compared with the control. Chloridazon in concentrations 27, 135 and 270 μg/L caused delay ontogenetic development and slower growth. Histopathological changes in hepathopancreas were found in two highest tested concentrations (135 μg/L and 270 μg/L). Crayfish behaviour was not altered in control vs. exposed animals, while the activity parameters tend to decline with increasing chloridazon concentrations.

Keywords: antioxidant biomarkers • behaviour • early ontogenetic • pyridazinone • toxicity