Garcia and colleagues, 2024

García SM, Curtis AN, Hartman JH, Reinhofer JP, Sawyer EK, Larson ER. 2024. Does crayfish molting affect environmental DNA detectability? Freshwater Crayfish 29(1): 37-47. https://doi.org/10.5869/fc.2024.v29-1.37

Abstract

While previous studies have explored the impact of behavior and life history on environmental DNA (eDNA), little research has been conducted on the impact of molting on eDNA detectability and particle size for aquatic arthropods like crayfish. To address this knowledge gap, we conducted a study examining how molting affects eDNA detectability over a range of particle sizes using marbled crayfish (Procambarus virginalis Lyko, 2017). We collected water samples from aquariums at pre- and post-molt time intervals and filtered our samples using sequential filtration from large to small filter pore sizes. We found that molting had a weak negative effect on eDNA detectability, and P. virginalis eDNA was most detectable throughout the study at our largest filter pore size (5.0 µm) regardless of molt status. Additionally, time spent in aquariums had a strong, positive effect on eDNA detectability for P. virginalis. Given that molting had a weak effect on eDNA detectability for our study crayfish, we suggest that researchers align their sampling efforts with other seasonal life history events, like reproduction or egg extrusion, that have been demonstrated to improve eDNA detectability.

 

Keywords: None provided.

2024 was a decent year for Marmorkrebs research

It’s time for our annual* tradition to look at the trendlines for marbled crayfish research...

 

 

I can’t say that I am super excited by what seems to be a new normal for Marmorkrebs research. There is a stronger need for research than ever, given that the number of countries with introduced Marmorkrebs just keeps growing. South Korea was added to the map of countries with confirmed introductions (although the discovery was a while back).

Meanwhile, Minnesota banned Marmorkrebs. And I am concerned that these bans are not having any exemptions for bona fide scientific research.

Previous year end reviews

2008 was the best year ever for Marmorkrebs research

2009 was tied for the best year ever in Marmorkrebs research

2010 was the best year ever for Marmorkrebs research

2011 was not the best year ever for Marmorkrebs research

2012 was an average year for Marmorkrebs research

2013 was the second best year ever for Marmorkrebs research

2014 was a good year for Marmorkrebs research

2015 was the best year ever for Marmorkrebs research

2016 was the best year ever for Marmorkrebs research

2017 was the second best year ever for Marmorkrebs research

2018 was the second best year ever for Marmorkrebs research

2019 was the second best year ever for Marmorkrebs research

2020 was not the best year for Marmorkrebs research

2021 was the third best year ever for Marmorkrebs research

2022 was a slow year for Marmorkrebs research

* Except 2023. Sorry. Missed that one.

Kamburska and colleagues 2024

Kamburska L, Sabatino R, Schiavetta D, De Santis V, Ferrari E, Mor J-R, Zaupa S, Garzoli L, Boggero A. 2024. A new misleading colour morph: is Marmorkrebs the only “marbled” crayfish? BioInvasions Records 13(4): 949-961. https://doi.org/10.3391/bir.2024.13.4.09

Abstract

We describe the occurrence of two unusually coloured crayfish individuals in two different locations in northwestern Italy (lakes Orta and Comabbio). They represent the first record in Italy of a marbled colour morph of Procambarus clarkii. Species assignment through morphological analyses was confirmed by molecular identification. Different body parts from the adult marbled coloured male and female, together with eggs and juveniles were analysed and blasted in GeneBank. All the sequences
were identified as P. clarkii, with a query coverage ≥ 99.0% and a percentage identity ≥ 99.7%. Based solely on external appearance, this new morphotype may lead to misinterpretation of taxonomic identification, being this colour morph very similar to the Marmorkrebs P. virginalis. A marbled female of P. clarkii could be wrongly attributed to Marmorkrebs when identification keys and molecular taxonomy are not considered to complement each other. The marbled morph of P. clarkii not only illustrates how varicoloured are the members of the family Cambaridae, but it also suggests that marbled colour alone is inadequate to identify a species. Therefore, it is recommended to consider this new colour in the morphological identification of the adult red swamp crayfish P. clarkii. The approach that integrates both molecular and morphological information improves promptly species taxonomy towards timely and appropriate management measures.

 

Keywords: DNA barcoding • integrative taxonomy • morphological analyses • morphotype • phenotypic plasticity • red swamp crayfish

Łabęcka 2024

Łabęcka AM. (2024). The 28th Polish Benthological Workshop. Folia Malacologica 32: 285-287. https://doi.org/10.12657/folmal.032.024

Abstract

Without abstract. Excerpt:

The awards committee... evaluated the presentations and posters by young scientists. This year, prizes were exclusively awarded for oral presentations. The winners were Przemysław Piekarczyk... and Kamil Wiśniewski, a doctoral student at Nicolaus Copernicus University in Toruń, for his talk on Clonal invasion: habitat preferences of juvenile, parthenogenetic marbled crayfish (Procambarus virginalis). 

 Keywords: None.

Jeong and Choi, 2024

Jeong H, Choi JH. 2024. Assessing the invasive risk of Procambarus virginalis (marbled crayfish) in South Korea. Journal of Ecology and Environment 48: 47. http://doi.org/10.5141/jee.24.087

Abstract

Background: Introducing invasive alien species can reduce biodiversity by interfering with native species or spreading disease and having socioeconomic consequences. Therefore, international society has set goals for preventing and suppressing the introduction and spread of invasive alien species. Nevertheless, humans intentionally introduce and release alien species into the wild, facilitating their invasion. Procambarus virginalis (marbled crayfish) is a Decapoda invertebrate sold for ornamental purposes. Ecological repercussions are anticipated because individuals have been verified to exist in the wild in South Korea. P. virginalis, believed to have originated in Europe and North America, is parthenogenetic. Therefore, there is concern that its population may quickly expand in the natural environment.

Results: This study examined the invasion risk of P. virginalis in South Korea and predicted its dispersal under future climatic circumstances. The habitat suitability for P. virginalis in Europe, North America, and Northeast Asia was determined using an ensemble species distribution model, and climatic niches were compared. Furthermore, the distributions of South Korea under the SSP2-4.5 and SSP5-8.5 scenarios are provided. The Northeast Asian region had habitat suitability comparable to that of Europe, and there was evidence that its climatic niche overlapped Europe (Schoener’s D = 0.29). In the future climatic scenario, 38% of South Korea is at risk of moderate to low invasion. The human disturbance index was the most critical variable in the distribution.

Conclusions: We believe the hazards of its invasion of South Korea are significant. Additionally, there is a high possibility that they will be established in nature due to artificial releases. Therefore, continuous monitoring and appropriate management are needed for areas with a high risk of P. virginalis invasion.

 

Keywords: ensemble species distribution model • human influence index • invasive species • niche overlap • Procambarus virginalis

 

Marbled crayfish in Korea

An interesting paper by Park and Jeon (2023) mentioned that South Korea imports about 78,000 crayfish as pets a year from 2018 to 2022. They describe 34 species imported.

 

I was surprised to see that marbled crayfish are not one of those species listed as being in the Korean pet trade at all. Usually they would be not only widely available, but one of the highest risk species.

 

But this YouTube video strongly suggests marbled crayfish are available in Korea.

 

Reference

Park Y, Jeon Y. 2023. A study on the import status of pet freshwater crayfish and potential invasive alien species crayfish in Korea. Korean Journal of Ecology and Environment 56(3): 242-249. https://doi.org/10.11614/KSL.2023.56.3.242
 

World of Crayfish™ database and website

World of Crayfish™ is an ambitious new website that shows the geographic distribution of crayfish species in near real-time.

Of course, I checked for whether there was a Marmorkrebs map. There is! Click to enlarge!

 

It’s clearly out of date in some ways. I expected to see records from Madagascar, as several localities published in peer-reviewed journals have been available for some time. On the other hand, there seem to be new records that I have not found yet, like in southern France.

Nevertheless, this seems like a much more organized effort that might eventually supplant my own map of Marmorkrebs introductions.

External link

https://world.crayfish.ro

Reference

Ion MC, Bloomer CC, Bărăscu TI, Oficialdegui FJ, Shoobs NF, Williams BW, Scheers K, Clavero M, Grandjean F, Collas M, Baudry T, Loughman Z, Wright JJ, Ruokonen TJ, Chucholl C, Guareschi S, Koese B, Banyai ZM, Hodson J, Hurt M, Kaldre K, Lipták B, Fetzner JW, Cancellario T, Weiperth A, Birzaks Jn, Trichkova T, Todorov M, Balalaikins M, Griffin B, Petko ON, Acevedo-Alonso A, D’Elía G, Śliwińska K, Alekhnovich A, Choong H, South J, Whiterod N, Zorić K, Haase P, Soto I, Brady DJ, Haubrock PJ, Torres PJ, Şadrin D, Vlach P, Kaya C, Woo Jung S, Kim J-Y, Vermeersch XHC, Bonk M, Guiaşu R, Harlioğlu MM, Devlin J, Kurtul I, Błońska D, Boets P, Masigol H, Cabe PR, Jussila J, Vrålstad T, Beresford DV, Reid SM, Patoka J, Strand DA, Tarkan AS, Steen F, Abeel T, Harwood M, Auer S, Kelly S, Giantsis IA, Maciaszek R, Alvanou MV, Aksu Ö, Hayes DM, Kawai T, Tricarico E, Chakandinakira A, Barnett ZC, Kudor ŞG, Beda AE, Vîlcea L, Mizeranschi AE, Neagul M, Licz A, Cotoarbă AD, Petrusek A, Kouba A, Taylor CA, Pârvulescu L. 2024. World of Crayfish™: A web platform towards real-time global mapping of freshwater crayfish and their pathogens. PeerJ 12: e18229. https://doi.org/10.7717/peerj.18229