26 November 2024

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
 

16 October 2024

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!

 

Screenshot of World of Crayfish website showing distribution of marbled crayfish Procambarus virginalis.

It’s clearly out of date in some ways.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

04 October 2024

Steen and colleagues 2024

Poster about burbot and catfish as control agents for marbled crayfish
Steen F, Scheers K, Abeel T, Claeyé J, Hermans V, Riascos Flores L,  Maex B, Vermeylen M, Adriaens T. 2024. Preliminary assessment of the native benthic predators, burbot (Lota lota) and catfish (Silurus glanis), as biological control agents for marbled crayfish. Poster presented at IAA24 Symposium of the International Association of Astacology, 16-20 September 2024, Zagreb, Croatia. https://lirias.kuleuven.be/retrieve/776025 (PDF)

Abstract

Invasive crayfish have become well-established in Flanders. Most of the species are widespread and eradication seems improbable. Yet, managers are looking for control measures to mitigate the density dependent impacts of invasive crayfish. This preliminary experiment explores predation of two benthic predatory fish burbot (Lota lota) and European catfish (Silurus glanis) on the marbled crayfish (Procambarus virginalis) and evaluates their potential for use as a future control measure.
 

Keywords: None provided.


Edit, 26 November 2024: YouTube video, apparently by the first author, showing some foraging behaviour of the European catfish:

 

15 September 2024

Thammatorn and colleagues 2024

inforgraphic showing crayfish exposed to diphenhydramine for 96 hours causing different effects on different tissue types.

Thammatorn W, Kouba A, Nováková P, Žlábek V, Koubová A. 2024. Effects of diphenhydramine on crayfish cytochrome P450 activity and antioxidant defence mechanisms: First evidence of CYP2C- and CYP3A-like activity in marbled crayfish. Ecotoxicology and Environmental Safety 285: 117035. https://doi.org/10.1016/j.ecoenv.2024.117035


Abstract

Growing evidence has reported that diphenhydramine (DPH), an ionisable antihistamine, is widely present in surface waters across the world. Relative to vertebrates studied, its impact on invertebrates, particularly concerning cytochrome P450 (CYP) metabolism and oxidative stress, remains poorly understood. In this study, we aimed to investigate the effects of 2, 20, and 200 µg/L DPH on marbled crayfish (Procambarus virginalis) after 96-h exposure. Specifically, we assessed CYP activity, antioxidant enzyme responses, and acetylcholinesterase (AChE) activity in gills, muscle, and hepatopancreas. The crayfish CYP metabolised fluorogenic CYP-metabolic substrates of 7-benzyloxy-4-trifluoromethylcoumarin (BFC) and dibenzylfluorescein (DBF), which evidenced the activity of CYP2C and CYP3A isoforms, well known in mammalian detoxification metabolism. Both BFC and DBF dealkylations showed a positive correlation with each other but were negatively correlated to water and haemolymph DPH concentrations. Exposure to 200 µg/L DPH elicited an apparent inhibition trend, albeit not significant, in BFC- and DBF-transformation activities in crayfish. Other tested 7-benzyloxyresorufin and 7-pentoxyresorufin substrates were poorly metabolised, suggesting their relatively low activity or the lack of mammalian-like CYP1A and CYP2B isoforms in marbled crayfish. The significant modulation of antioxidant enzymes was demonstrated in gills and hepatopancreas. The exposure to DPH did not alter the activity of AChE. Integrated biomarker response version 2 showed the highest cumulative effect of DPH exposure on gills, implying that gill tissue is the most reliable matrix for evaluating DPH toxicity. Activities of glutathione peroxidase and glutathione-S-transferase were the most deviated determinants among the investigated biomarkers, providing insights into the DPH toxicity in crayfish. This study brought the first insight into utilising the fluorogenically active substrates BFC and DBF to demonstrate the CYP involvement in the detoxification metabolism in marbled crayfish. Further, our results provided information on valuable antioxidant defence mechanisms and biomarker responses for a future DPH toxicity assessment in aquatic organisms.

 

Keywords: cytochrome P450 • oxidative stress • biomarker • aquatic invertebrate • antihistamine 

 

Open access logo

 

08 September 2024

Marmorkrebs in Tanzania?

My usual Google alerts for marbled crayfish are usually misses, but this immediately caught my eye:

 

 

Transcript:

 

What if I told you a crayfish could clone itself and feed a nation? Welcome to the marbled crayfish saga.

 

Back in 1995 a reproductive accident in an aquarium created the marbled crayfish, a
freshwater Houdini that can clone itself. (That year is the first unambiguous record, not when the species originated, which was probably some time before that. And the origin may not have been an “accident in an aquarium.” This is unknowable. - ZF)

 

Sounds like sci-fi, right? This little critter with its army of identical offspring spread rapidly across continent in Tanzania where protein sources can be scarce and expensive. This invasive species turned into an unexpected hero. Locals quickly figured out that the marbled crayfish is not just easy to catch but also packed with nutrients. Talk about turning lemons into lemonade.

 

So from an accidental aquarium escapade to a cheap protein source for Tanzanians, the marbled crayfish is redefining what it means to be an invasive species. Nature enthusiasts, keep an eye out. This crayfish is making waves, one clone at a time.

 

If so, this would be the first record of marbled crayfish in Tanzania. But several things about this video make me skeptical.

 

The video has no references, so the source of this information is unknown. The last big review of crayfish introductions in Africa (Madzivanzira et al. 2020) makes only only mention of Tanzania:

 

(A)necdotal records suggest that P. clarkii may have established in the Kagera River, which enters Lake Victoria on the Uganda–Tanzania border.

 

I find it hard to believe that marbled crayfish are so widespread in Tanzania that there is no record in the scientific literature or anywhere else that I can find. (A Google search first brings up pictures of Tasmanian crayfish, so sure is the search engine that I must have meant Australia and not Africa.) It sounds like Tanzania has maybe been confused with Madagascar, where marbled crayfish are well established.

 

This crayfish clips show many species that are almost certainly not marbled crayfish. Only the very first shot seems to be marbled crayfish; the remainder seem to be Louisiana red swamp crayfish (Procambarus clarkii) and some other north American species (maybe Orconectes rusticus?).

 

Finally, the video implies, “How big a problem is it really if people can eat them?” I hate that this implies that we don’t have to take invasive species seriously.


Edit, 13 September 2024: The creator admitted this was suppressed to be Madagascar, not Tanzania. There’s a new video with the correct country.



References

Madzivanzira TC, South J, Wood LE, Nunes AL, Weyl OLF. 2020. A review of freshwater crayfish introductions in Africa. Reviews in Fisheries Science & Aquaculture 29(2): 218-241. https://doi.org/10.1080/23308249.2020.1802405

External links

Marbled Crayfish: From Aquarium Accident to Tanzania's Protein Powerhouse!

Related posts

Why people can’t take invasive crayfish seriously

03 September 2024

Marmorkrebs featured in Indian news article

India Today has a nice little feature on animals that reproduce asexually. I am a little disappointed that marbled crayfish only come in at the middle of the list, but the photo they used is nice.

External links

7 animals that reproduce without mating

01 September 2024

Musil and colleagues 2024

Cover of "Journal of Vertebrate Biology"
Musil M, Let M, Riebel M, Balzani P, Kouba A. 2024. Non-native three-spined stickleback, a small but voracious predator of invasive crayfish. Journal of Vertebrate Biology 73: 24060. https://doi.org/10.25225/jvb.24060

Abstract

Numerous fish and crayfish species are invasive in freshwater ecosystems, where they interact. In this study, we performed two experiments to investigate adult three-spined stickleback Gasterosteus aculeatus predation on early juvenile invasive crayfish in Europe. The first experiment focused on evaluating predation upon early juveniles of three invasive species (the marbled crayfish Procambarus virginalis, the spiny-cheek crayfish Faxonius limosus, and the signal crayfish Pacifastacus leniusculus) with varying exposure times (one, three and six hours), revealing crayfish species-specific vulnerabilities and the role of exposure duration. Marbled and spiny-cheek crayfish juveniles were more susceptible to three-spined stickleback predation than signal crayfish. Nevertheless, larger signal crayfish suffered more damage caused by the fish predator. The second experiment assessed the role of size in predation efficiency, using three different size groups of marbled crayfish juveniles as prey of adult three-spined sticklebacks during three hours of exposure. In this second experiment, we found the predation level to be size-dependent, with the smallest group of juveniles (20-80 mg) being preyed upon the most, and the largest group (250-350 mg) the least. The efficient predation of the three-spined stickleback on large juvenile crayfish underscores its potential ecological impacts also on native crayfish.


Keywords: behavioural ecology • biological invasion • non-native crayfish • non-native fish • predation