Brys and colleagues 2026

Brys R, Herder J, Everts T, 2026 eDNA monitoring of invasive Marbled crayfish and impact assessment on native amphibians. ARPHA Conference Abstracts 9: e203368. https://doi.org/10.3897/aca.9.e203368

 Abstract

Invasive species are a major driver of global biodiversity loss, particularly in freshwater ecosystems. The marbled crayfish (Procambarus virginalis), a parthenogenetic invader with exceptional capacity for rapid spread, poses an increasing threat to amphibian communities across Europe. Here we present the implementation of environmental DNA (eDNA)-based monitoring to assess the distribution, ecology, and ecological impacts of this species on native amphibian communities. We developed and validated species specific digital droplet PCR (ddPCR) assays for sensitive detection and absolute quantification of marbled crayfish and several native amphibians of conservation concern. Mesocosm experiments and field validations demonstrated that ddPCR enables highly sensitive detection and reliable estimation of population size from eDNA samples. Next, we conducted a four-year monitoring program across a large number of ponds and fens in the Hatertse Vennen (the Netherlands), a nature reserve and biodiversity hotspot supporting protected species such as the great crested newt (Triturus cristatus), moor frog (Rana arvalis), and spadefoot toad (Pelobates fuscus). This study revealed that marbled crayfish is far more widespread and abundant than previously assumed, with ongoing annual expansion. Concurrent amphibian eDNA monitoring indicated strong negative effects associated with crayfish presence, including substantial population declines at invaded sites. These findings are now informing targeted management actions, including eradication efforts and the implementation of dispersal barriers designed to limit crayfish spread while maintaining amphibian connectivity. Our study highlights ddPCR-based eDNA monitoring as a powerful tool for invasive species detection, population assessment, and impact evaluation. More broadly, this approach provides a scalable framework for conserving amphibian biodiversity in vulnerable freshwater ecosystems

 

Keywords: Amphibian conservation • environmental DNA (eDNA) • invasive species management • Procambarus virginalis  

 

Ham and colleagues 2026

Ham S-N, Nakata K, Soma R, Shirako T, Ishimori H, Ikehara K, Nakamura M, Kanno T, Asano M. 2026. Evidence of establishment and range expansion of the invasive marbled crayfish, Procambarus virginalis Lyko, 2017 (Decapoda: Astacidea: Cambaridae) in Okinawa, Japan. Journal of Crustacean Biology 46(3): ruag043. https://doi.org/10.1093/jcbiol/ruag043

Abstract

The invasive marbled crayfish, Procambarus virginalis Lyko, 2017, which reproduces by obligate parthenogenesis, has undergone rapid global expansion in recent decades. Records of this species in Japan, however, have been limited, and evidence of establishment and spread has remained scarce. We investigated the occurrence and population characteristics of P. virginalis in Okinawa, southern Japan. In addition to the previously reported population in a park pond in Naha City, we documented the species at two further sites: a channel-shaped biotope adjacent to an elementary school approximately 990 m from the park pond and a water source with its exact location withheld in Urasoe City, approximately 6.4 km from a different watershed. A total of 38 individuals were collected, including one adult carrying 43 juveniles at the channel-shaped biotope, providing clear evidence of successful reproduction. Size distributions indicate the presence of individuals at or near sexual maturity at all three sites. Genetic analyses revealed identical genotypes among individuals from all sites, indicating a clonal lineage and suggesting a shared origin or introduction from a common source. By contrast, variation in the presence of associated symbiotic ostracods among sites may provide insights into the introduction history of this species. These findings demonstrate a wider distribution of P. virginalis in Okinawa than previously recognized and suggest the potential for further spread. Given the high freshwater biodiversity and endemism in the region, continued spread of this species may pose a significant ecological risk, underscoring the need for monitoring and management.

Keywords: None provided.

 

Poirier and colleagues 2026

Poirier LA, Pratt CJ, Hope E, Kingsbury S, McAlpine DF, LeBlanc F, Burbidge C. 2026. First record of the nonindigenous crayfish, Procambarus virginalis Lyko, 2017, in Nova Scotia, Canada. BioInvasions Records 15(2): 393-402. https://doi.org/10.3391/bir.2026.15.2.14

Abstract

Herein, we report the first record of the cambarid marbled crayfish (Procambarus virginalis Lyko, 2017) in the province of Nova Scotia, Canada. Originating from the pet trade in Germany, the marbled crayfish is a parthenogenic species that is known to be a rapid colonizer of multiple habitat types and can outcompete native species. Multiple collections of specimens were made during 2023 and 2024 in two small backyard ponds in the southwestern area of the province. Genetic confirmation was completed by sequencing a portion of the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene using universal marine invertebrates PCR primers. A 100% match was obtained to publicly available DNA reference sequences. This species represents a potential threat to Nova Scotian waterways, as disruptions to food web organization are anticipated. With limited options for eradication and control, the potential for the mitigation or reversal of invasion impacts is low.

Keywords: marbled crayfish • range expansion • crawfish • introduction • vectors 

 

Balzani and colleagues 2025

Balzani P, Musil M, Weiperth A, Bláha M, Kubec J, Ruokonen TJ, Ercoli F, Bányai ZM, Buřič M, Veselý L, Kouba A. 2025. Seasonal changes in trophic ecology of co-occurring freshwater invasive species at a thermal locality. Hydrobiologia 852(17): 4493-4512. https://doi.org/10.1007/s10750-025-05872-8

Abstract

We investigated the trophic ecology of three non-native crayfish species (the marbled crayfish Procambarus virginalis, the red swamp crayfish Procambarus clarkii and the spiny-cheek crayfish Faxonius limosus) and two non-native fishes (the eastern mosquitofish Gambusia holbrooki and the three-spined stickleback Gasterosteus aculeatus) from two sections of a thermal tributary of the Barát brook in Budapest (Hungary) over the four seasons using carbon and nitrogen stable isotope analysis. All crayfish species occupied an omnivore trophic position in almost all sections and seasons. On the other hand, both fishes had a predatory trophic position, with G. aculeatus occupying a higher position than G. holbrooki. These patterns are confirmed by the results of the mixing models, showing spatial and temporal changes in the diet composition. We also found interspecific differences in the crayfish trophic niche in both sections during summer and overlapped niches in the other occasions, while fish had always segregated niches. Crayfish showed interseasonal differences in the trophic niche in both sections, while fish showed seasonal niche shifts only in the upper section. Our results show a considerable plasticity in the trophic ecology of the studied non-native populations, suggesting that the temperature variability gradient has no important role in determining their trophic niche. 

Keywords: Alien species • invasive species • stable isotopes • freshwater ecology • competition • predation

 

 

Marin and colleagues, 2025

Marin IN, Statkevich SV. 2025. The first discovery of the invasive marbled crayfish Procambarus fallax (Hagen, 1870) in Crimea. Arthropoda Selecta 34(3): 359–364. https://kmkjournals.com/journals/AS/AS_Index_Volumes/AS_34/AS_34_3_359_364

Abstract

Data on the discovery of the invasive marbled crayfish Procambarus fallax (Hagen, 1870) (Decapoda: Cambaridae) in the western Crimea, in the lower streams of the Alma and Belbek rivers, is presented. This is the first report of its presence on the peninsula, adding another invasive species to the list in the Russian Federation. Phylogenetic analysis reveals that the crayfish found in Crimea share the same genetic haplotype as other invasive subpopulations from Europe, Sweden, Japan, and parts of Florida. The European subpopulation has a single haplotype, suggesting a relatively recent introduction, likely from a single parent within its native range in Florida. In the case of the lower reaches of the Alma and Belbek rivers, we propose a hypothesis based on the possible involvement of large migratory birds, such as hissing swans and ducks, and plants attached to their paws in the spread of juvenile crayfish to nearby water reservoirs.

Keywords: invasion • Decapoda • Crustacea • crayfish • COI mtDNA • Crimean Peninsula

Teesalu and colleages 2025

Teesalu P, Muuga JM, Hurt M, Kaldre K, Nõges T, Ercoli F. 2025. Effects of temperature on marbled crayfish (Procambarus virginalis, Lyko 2017) invasion ecology. Hydrobiologia: 852: 3541–3558. https://doi.org/10.1007/s10750-025-05828-y

Abstract

 

The marbled crayfish (Procambarus virginalis) is an invasive freshwater species spreading across Europe. Understanding its establishment and distribution is crucial, particularly in relation to temperature. This study examined the role of water temperature in marbled crayfish invasion in a warm outflow channel of a power plant in Estonia. We hypothesized that warmer water temperatures and the temperature gradient along the channel would influence crayfish establishment, distribution, and trophic niche. Temperature loggers revealed a distinct gradient, with the channel being warmer than the adjacent reservoir, providing a more suitable habitat for crayfish. Stable isotope analysis (¹³C and ¹⁵N) with MixSIAR and SIBER models showed distinct trophic niches along the channel: crayfish at the head of the channel consumed macroinvertebrates and macrophytes, while those at the mouth mainly consumed macroinvertebrates and periphyton. Additionally, crayfish shifted from eating primary consumers in spring and summer to primary producers in autumn. Water temperature was a key factor in crayfish establishment, but food availability also likely influenced their distribution. This study highlights the role of water temperature and ecological factors in the invasion dynamics of marbled crayfish, especially in the context of global warming.

 

Keywords: Stable isotopes • trophic niche • invasive species • population dynamic • temperature effect

Buřič and colleagues 2025

Buřič M, Ložek F, Görner T, Čuprová V, Kožený P, Mojžišová M, Vlach P, Štruncová E, Petrusek A, Kouba A, Svobodová J. 2025. Difficult to deal with: attempts for eradication of marbled crayfish from a small urban pond. Management of Biological Invasions 16(2): 443–464. https://doi.org/10.3391/mbi.2025.16.2.08

Abstract

The marbled crayfish is an emerging invasive species, mainly due to parthenogenetic reproduction and high adaptability. Its successful eradication seems to be possible only in early detected populations and under favourable conditions. The population of marbled crayfish was discovered in a small urban pond in Prague, Czech Republic, in August 2020. Shortly afterwards, management was initiated with the aim of complete eradication. The pond was harvested and drained twice in November 2020 and October 2021. The crayfish were collected, the exposed pond bottom was treated by liming and left dry over winter. Predatory fish were stocked in the pond after refilling. Survival of the crayfish after the pond draining in 2021 was likely facilitated by up to 40 cm deep burrows found under large boulders. No specimens were observed in the nearby stream and marbled crayfish presence was not detected by environmental DNA screening in the stream and three other standing waters in the vicinity. The combined efforts resulted in a reduction in crayfish densities by an order of magnitude between successive harvests, but complete eradication of marbled crayfish was not achieved by 2023, as individual juveniles were captured during monitoring in the following two years. The perch-dominated fish stock apparently exerts a strong predation pressure that may control the crayfish population, as no marbled crayfish were captured during monitoring in 2024. The current status of the population is unclear, and further monitoring is warranted. Effective cooperation between different institutions and stakeholders has been successfully established, and the public and stakeholders have been educated about the risks of invasive species. However, with prolonged activities aiming to eradicate the crayfish, we also experienced decrease of public support for further radical actions. This experience provides a solid basis for future invasive crayfish management activities at sites with similar conditions.

 

Keywords: invasive species • management • biological invasions • freshwater • crustacean • macroinvertebrates 

 

Short course on Marmorkrebs

The Invasive Species Center is offering a short course on Marmorkrebs.

The course description:

This short course will provide an overview on crayfishes, with a particular focus on marbled crayfish biology, spread, and impacts.

Lesson 1: Introduction to Aquatic Invasive Species

Lesson 2: Introduction to Crayfishes

Lesson 3: Marbled Crayfish Biology

Lesson 4: Marbled Crayfish Impacts

Lesson 5: Preventing the Spread of Invasive Crayfishes

This course takes about 2 hours. Score an 80% on the final exam, and score a certificate of completion! 

The Center’s Instagram page has a discount code that lets you take the course for free until the end of May! If you happen to be reading this in June 2025 or later, sorry that it is no longer free, but should still be affordable.

External links

Invasive Species Training

Invasive Species Center on Instagram (contains discount code) 

Talking Marmorkrebs to the streets

 

 

Pleased to hear that Marmorkrebs were part of a show promoting outdoor activities,

 

Brianna Naklicki from the Ontario Federation of Anglers and Hunters was handing out information booklets to visitors passing by. She works for the organization’s invasive species awareness program.

On a table in front of her are jars containing examples of species of concern in the province, including zebra mussels and marbled crayfish.

Her job at the show was to spread awareness about invasive species around lakes and forests to all who will listen.

 

Ontario is, so far, the only place in North America where Marmorkrebs have been found in the wild, and is the largest jurisdiction to ban Marmorkrebs.

External links

Outdoor show hooks nature lovers into shopping local

Update on Marmorkrebs in Warsaw, Poland

A couple of recent news articles are reporting on the presence of Marmorkrebs in Warsaw. This location was already in my map of Marmorkrebs introductions. A bioblitz located seven individuals in Morskie Oko Park back in 2019.

Fast forward six years to 2025, and the population is estimated at 100,000 crayfish.

 

The article notes that there are removal efforts, but they can’t drain the pond, so culling them requires catching them by hand or trap. And in typical local media style, they stress the expense.

 

I do appreciate the safety warning:

 

 The expert emphasized that rakes do not attack a person if they are not provoked to do so. 

I don’t know of any crayfish that voluntarily attacks people with anything more than a pinch.

External links

Wpuścił raka do stawu w Warszawie. "Doprowadził do niepowstrzymanej ekspansji" (He released a crayfish into a pond in Warsaw. “He led to unstoppable expansion”)

 

Warszawa zmaga się z inwazją raka marmurkowego. Ekspert ostrzega (Warsaw is struggling with marbled crayfish invasion, expert warns)

 

Photo by Adrian Grycuk - Own work, CC BY-SA 3.0 pl, https://commons.wikimedia.org/w/index.php?curid=101324805

The Crayfish Almanac

Don’t know how I missed this last year, but Michigan State University released Great Lakes Almanac to Invasive Crayfish.

It has one of the best short identification guides for Marmorkrebs I’ve seen. Click to enlarge!

Marbled crayfish (or marmokrebs) originated in the aquarium trade and are often called the self-cloning crayfish. All marbled crayfish are female and the offspring are clones. This species is of high concern because a single individual can produce an entire population in a short time.

This species has a distinct marbling pattern, but other species may look similar. Male crayfish with this pattern are not marbled crayfish.

To determine if its a female, look for a round pocket-like feature located on the underside between the last pair of walking legs. This is the sperm pouch (called an ‘annulus ventralis’) .

External links

Great Lakes Almanac to Invasive Crayfish 

Golubev and colleagues 2024a

Golubev AP, Ulashchyk EA, Bodilovskaya OA, Giginjak YG. 2024. Assessing the invasive potential of parthenogenetic marbled crayfish Procambarus virginalis Lyko, 2017 (Decapoda, Astacidea) in the water bodies of the temperate zone of Europe. Doklady Natsional’noi akademii nauk Belarusi = Doklady of the National Academy of Sciences of Belarus 68(2): 129–137. (In Russian). https://doi.org/10.29235/1561-8323-2024-68-2-129-137

 Abstract

The experiment examined the effect of temperature on the parameters of reproduction and growth in female marbled crayfish. At temperatures close to 20 °C, females began to reproduce at 10–11 months with a body weight of 0.84–1.20 g, but up to 80 % of their egg clutches were nonviable. The duration of egg embryogenesis with an increase in temperature from 16–17 to 26–27 °C decreased from 66–69 days to 21–24 days with a lower temperature development threshold equal to 13.1 °C. A similar molting value that determined the growth rate of individuals in juveniles weighing up to 0.34 g was 13–14 °C, but in sexually mature females it decreased to 5 °C. In water bodies of the temperate zone with a short growing season, females were able to reach sexual maturity only in the third summer of life and produced no more than two clutches of eggs during their life cycle. Hence, the invasive potential of marbled crayfish in the temperate zone of Europe is very limited.

Аннотация

В эксперименте исследовано воздействие температуры на параметры размножения и роста у самок мраморного рака. При температурах, близких к 20 °С, самки начинали размножаться в возрасте 10–11 месяцев при массе тела 0,84–1,20 г, однако до 80 % их кладок яиц были нежизнеспособными. Длительность эмбриогенеза яиц при повышении температуры от 16–17 до 26–27 °С снижалась от 66–69 до 21–24 суток при нижнем температурном пороге развития, равном 13,1 °С. Аналогичный показатель для частоты линек, которая определяет скорость роста особей, у молоди массой до 0,34 г составлял 13–14 °С, но у половозрелых самок он снижается до 5 °С. В водоемах умеренной зоны с коротким сезоном вегетации самки способны достичь половой зрелости лишь на третье лето жизни и произвести за жизненный цикл не более двух кладок яиц. Отсюда инвазивный потенциал мраморного рака в умеренной зоне Европы весьма ограничен.

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

 

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

Sánchez and colleagues 2024

Sánchez O, Oficialdegui FJ, Torralba-Burrial A, Arbesú R, Valle-Artaza JM, Fernández-González Á, Ardura A, Arias A. Procambarus virginalis Lyko, 2017: A new threat to Iberian inland waters. Ecology and Evolution 14(5): e11362. https://doi.org/10.1002/ece3.11362

Abstract

An eco-monitoring programme to assess faunal biodiversity in the main rivers of the northern Iberian Peninsula (Spain) reveals the first occurrence of the marbled crayfish Procambarus virginalis (Decapoda: Cambaridae) in Iberian inland waters. Iberian specimens have been identified by combining morphological and genetic traits. We discuss the most plausible pathways and introduction vectors, its potential invasiveness and subsequent impacts on host localities. Our preliminary results raise concern about the potential threat of P. virginalis to native fauna and ecosystem dynamics, as P. virginalis was found in an area of great cultural and ecological importance with relevant populations of endangered species. Due to the invasive history of the marbled crayfish, eradication of these individuals is urgent. This study confirms the importance of early warning systems for exotic species, keeping the population, forest guards and field technicians informed about potential invasive species to execute a rapid and effective response.  

Keywords: None provided.

Yanai and colleagues 2024

Yanai Z, Guy-Haim T, Kolodny O, Levitt-Barmats Ya, Mazal A, Morov AR, Sagi A, Truskanov N, Milstein D. 2024. An overview of recent introductions of non-native crayfish (Crustacea, Decapoda) into inland water systems in Israel. BioInvasions Records 13(1): 195-208. https://doi.org/10.3391/bir.2024.13.1.17

Abstract

Crayfish are known to effectively invade freshwater systems worldwide. Whilst no native crayfish species exist in Israel, three exotic species have been documented in recent years, and their introduction details are hereby discussed. Three of these introduction events, one of each species, were previously reported; one was established, one failed to establish, and the third was successfully eradicated. However, more recently, invasive crayfish have been independently detected multiple times, involving a variety of natural and artificial habitats. Altogether, three invasive crayfish species currently inhabit Israeli freshwaters: Cherax quadricarinatus, Procambarus clarkii, and Procambarus virginalis. They were found in fourteen independent cases, and at least five of them represent established populations. Similar to other crayfish invasions around the globe, we speculate that the invasive populations in Israel result from the intentional release of aquarium inhabitants, as well as from aquaculture escapees. The import and trade policy of aquatic organisms in Israel requires thorough revision to prevent future invasions. Thought should also be given to the prevention of the spread of the existing invasive populations as well as to their eradication, if possible.

Keywords:  Cherax quadricarinatus • Procambarus clarkii • Procambarus virginalis • aquarium release • invasive species • Levant

Hamr 2023

Hamr P. 2023. First record of the marbled crayfish in Canada/North America. Crayfish News 45(1-2): 1, 3. https://www.astacology.org/docs/cn/CrayfishNews_45(1-2)_hr.pdf (Direct link to PDF)

Abstract

Without abstract. First paragraph: 

 

Suspected marbled crayfish (Procambarus virginalis) were first reported in Southern Ontario in October 2021. The reports came from a Burlington City Park and were made by a naturalist (Ms. N. Bucik) as well as park staff who observed and photographed individual crayfish walking on a nature path as well as on a nearby football (soccer) pitch. All the reports were made near three stormwater ponds in the park where it was suspected the crayfish came from. (The identity of the crayfish was subsequently confirmed by EU crayfish experts when I showed the photos at IAA 23 in the Czech Republic in July 2022). 

Keywords: None provided.

Carneiro and colleagues 2023

Carneiro VC, Galil B, Lyko F. A voyage into the Levant: the first record of a marbled crayfish Procambarus virginalis (Lyko, 2017) population in Israel. BioInvasion Records 12(3): 829-836. https://doi.org/10.3391/bir.2023.12.3.18

Abstract 

The marbled crayfish, Procambarus virginalis (Lyko, 2017) is a novel parthenogenetic freshwater species that has rapidly colonized diverse habitats in Europe and Madagascar. Here we describe the first wild population of marbled crayfish in the Middle East. Numerous specimens, including gravid females, were collected in the waters of a spring on Mt. Carmel, Israel. The results from phenotypic, morphometric and genetic analyses showed the close relationship with other known populations, consistent with the clonal structure of the global marbled crayfish population. Our findings represent a considerable expansion of the known distribution range and further illustrate the role of anthropogenic activities in the dispersal of marbled crayfish.

Keywords: invasive species • freshwater crayfish • freshwater ecology • anthropogenic dispersal

Be on the lookout for Marmorkrebs, Ontario! Marmorkrebs finally found in North America

Burlington Today is reporting that Marmorkrebs have been found in Burlington, Ontario.

The details are hazy.

 

Marbled crayfish – an aquatic invasive species that is prohibited in the province – has been found in the Burlington area.

 

That’s the extent of actual reporting. The rest of the article is background information.

Edit, 6 August 2023: A Burlington Post article is a little more expansive.  It gives a general location (a city park).

Previously, another marbled crayfish was reported in the area on iNaturalist. (I actually went to where the iNaturalist sighting was to look around, but heard people had already looked and found nothing.) 

 

This Burlington marbled crayfish sighting is also on iNaturalist, from Premek Hamr, also known as “Dr. Crayfish.” Premek has extensive experience with Ontario crayfish, so it’s not as though this is an Ontario native being misidentified.

 

On Twitter, Hamr has been sharing pictures of multiple individuals, including juveniles. This indicates there is a breeding population at this location.

 

Ontario just banned marbled crayfish last year.

While this is a watershed moment in the worldwide invasive status of marbled crayfish, it is something that has been expected for a long time. It’s mostly surprising in that it didn’t happen a few years ago.

The map of Marmorkrebs introductions has been updated.

External links

Marbled crayfish sighting in iNaturalist

 

Premek Hamr on Twitter: One,  two , three, four

 

Be on the lookout for marbled crayfish in the Burlington area (Burlington Today)

 

‘Capable of cloning’: Invasive crayfish found in Burlington pond (Burlington Post)

‘Capable of cloning’: Invasive crayfish found in Burlington pond (Hamilton Spectator) 

Ontario Natural Resources and Forestry on Twitter

Related posts

Ontario prohibits Marmorkrebs

Arianoutsou and colleagues 2023

Arianoutsou M, Adamopoulou C, Andriopoulos P, Bazos I, Christopoulou A, Galanidis A, Kalogianni E, Karachle PK, Kokkoris Y, Martinou AF, Zenetos A, Zikos A. 2023. HELLAS-ALIENS. The invasive alien species of Greece: time trends, origin and pathways. NeoBiota 86: 45-79. https://doi.org/10.3897/neobiota.86.101778

Abstract

The current paper presents the first effort to organize a comprehensive review of the Invasive Alien Species (IAS) of Greece. For this purpose, a database was developed with fields of information on the taxonomy, origin, ecology and pathways of introduction of terrestrial, freshwater and marine species. Our database includes a) taxa in the Union’s list that are present in Greece, b) taxa already present in Greece and considered to be invasive, and c) taxa highly likely to enter Greece in the next 10 years and become invasive. The Database served as the starting point for the compilation of the National List of Alien Invasive Species (HELLAS-ALIENS) in compliance with the EU Regulation 1143/2014. Overall, the HELLAS-ALIENS comprises 126 species, i.e. 32 terrestrial and freshwater plant species, 14 terrestrial invertebrates, 28 terrestrial vertebrates, 30 freshwater fishes and invertebrates and 22 marine species. Terrestrial invertebrates, birds and mammals are mainly of Asiatic origin. Most of the terrestrial plants have their native geographical distribution in the Americas (North and South). Most of the freshwater invertebrates and fishes are of North American origin, while the majority of the marine species are of Indo-Pacific origin. The first records of IAS concern terrestrial plant species, and date back to the 19th century, while those in freshwater and marine ecosystems seem to have been systematically recorded some decades later. Regarding the pathways of introduction, most of the taxa arrived in Greece or are expected to arrive through escape from confinement and unaided. The majority of the terrestrial, freshwater and marine species have been evaluated as of High-risk for the indigenous biodiversity and only 3% of the species listed have been evaluated of Low-risk. Our results provide an important baseline for management and action plans, as required by the priorities set by the European Union through the Biodiversity Strategy for 2030.

 

Keywords: European Union • Invasive Alien Species Regulation • pathways of introduction • risk assessments • temporal trends

 

(Note: Marmorkrebs are listed as “Taxa not currently present in Greece but highly likely to be introduced within the next 10 years.”)