13 September 2018

Cover cray

Nice cover accompanying this blog post. It’s covering the Marmorkrebs genome paper that came out back in February, but better late than never! The photo is aces in any case.

External links

Decoding the mutant, all-female, self-cloning crayfish

Crayfish crimes

Prosecutions for anything to do with the aquarium trade is rare, but last week, news reported Justin Doyle Pierce, an American was prosecuted for selling crayfish as pets, in violation of the Lacey Act)

Pierce sold over $19,000 worth of crayfish illegally, and for this, he got a $500 fine, 20 hours of community service, and a year on probation. By my quick scan of the act, he could have received jail time and thousands of dollars in fines.

Is this sort of enforcement acting as a deterrent? It’s not clear. When someone can make that much money, the fine is little more than a clap on the wrist. The real penalty may not be the fine or the service, but the criminal record. Pierce wrote:

(T)his will result in my disqualification of future employment in areas related to wildlife and conservation.

External links

Feds pinch Camden County man for illegal crayfish sales
Overview of the Lacey Act (16 U.S.C. SS 3371-3378)
Lacey Act cases

Hossain and colleagues, 2018

Hossain MS, Patoka J, Kouba A, Buřič M. 2018. Clonal crayfish as biological model: a review on marbled crayfish. Biologia 73(9): 841-855. https://doi.org/10.2478/s11756-018-0098-2


Since the mid-twentieth century, numerous vertebrates and invertebrates have been used as model organisms and become indispensable tools for exploring a broad range of biological and ecological processes. Crayfish seem to be adequate models which resulted in their involvement in research. In the two decades since its discovery, ongoing research has confirmed that the marbled crayfish (Procambarus virginalis Lyko, 2017) is an ideal taxon in this regard, especially due to its almost continuous asexual reproduction providing a source of genetically identical offspring. This review provides an overview of the occurrence, biology, ecology, ethology, and human exploitation of marbled crayfish with primary focus on its use as a laboratory model organism as well as potential risks to native biota in case of its introduction. Genetic uniformity, ease of culture, and a broad behaviour repertoire fosters the use of marbled crayfish in epigenetics and developmental biology, as well as physiological, ecotoxicological, and ethological research. Marbled crayfish could be further exploited for basic and applied fields of science such as evolutionary biology and clonal tumour evolution. However, due to its high invasive potential in freshwater environments security measures must be taken to prevent its escape into the wild.

Keywords: model species • epigenetics • developmental biology • Procambarus virginalis • biological invasion

01 September 2018

Naboka and colleagues, 2018

Naboka A, Marenkov O, Kovalchuk J, Shapovalenko Z, Nesterenko O, Dzhobolda B. 2018. Parameters of the histological adaptation of Marmorkrebs Procambarus virginalis (Lyko, 2017) (Decapoda, Cambaridae) to manganese, nickel and lead ions pollution. International Letters of Natural Sciences 70: 24-33. https://doi.org/10.18052/www.scipress.com/ILNS.70.24


Manganese, lead and nickel are heavy metals, which are the primary fresh water toxic contaminants being in the most dangerous class of chemicals. Heavy metals cause functional disorders in the tissues and organs of hydrobionts, affecting their linear and weight indices, reproductive system, digestive and extraction organs. In our experiment on marbled crayfish Procambarus virginalis (Lyko, 2017) we studied the long-term effects of various concentrations of heavy metal ions on the physiological state and histostructure of tissues and organs. According to the results of research, it was found that among the studied heavy metals nickel ions influenced the weight indexes and mortality of crustaceans the most negatively. The results of morphometric studies on marbled crayfish indicate no significant differences between the control group and experimental one, but heavy metals influenced the form of the hepatopancerase lobes and the size of the lumen of the gland. Research on adipocytes of the connective tissue showed a significant difference between the size of cells under the influence of heavy metals. Dimensions of adipocytes fluctuated over a wide range from 144 μm2 to 537 μm2. In control group the adipocyte area was 406.96 μm2. Experimental studies of hemolymph showed that, under the influence of lead ions, a significant 1.4 times increase was observed in the area of hemolymph cells; when manganese and nickel were added, moderate decrease was observed in cells. It was found that under the influence of nickel, the area of round hyalinocytes has reduced by 1.7 times.

Keywords: Procambarus virginalis • glandulocytes • hepatopancreas • hemolymph • manganese • nickel • lead • crustaceans

16 August 2018

Soes, 2016

Soes DM. 2016. Onderzoek voorkomen marmerkreeft in Middelburg. Rapportnummer 16‐250. Bureau Waardenburg, Culemborg. https://doi.org/10.13140/RG.2.2.10943.82081


De marmerkreeft is een in Nederland exotische rivierkreeft die valt onder de recent inwerking getreden Europese exotenverordening (EU 1143/2014). Van de marmerkreeft zijn uit Nederland tot op heden geen populaties bekend (Koese & Soes, 2011; D.M. Soes eigen informatie). Voor de marmerkreeft is het dan ook van belang nieuwe vestigingen snel te signaleren zodat eventueel maatregelen kunnen worden genomen die verdere verspreiding tegengaan of zelfs eliminatie mogelijk maken.

In 2014 en 2015 zijn in het westen van Middelburg (omgeving Hugo de Grootlaan) twee vondsten van mogelijke marmerkreeften gedaan. Eén waarneming betrof een dood exemplaar in een brandgang. Het tweede exemplaar werd levend aangetroffen in een tuinvijver. Verder is er nog een ongedateerde waarneming van een levende kreeft in dezelfde brandgang. Deze informatie was voor de NVWA aanleiding nader onderzoek uit te voeren.

In onderhavig rapportage wordt beschreven:
  1. de definitieve determinatie van de gevonden kreeften;
  2. een inventarisatie naar het eventueel voorkomen van de soort in de directe omgeving van de genoemde vondsten;
  3. de kansen op verspreiding indien zij in het westen van Middelburg daadwerkelijk zou voorkomen.
Keywords: None provided.

(English translation with Google Translate and some guesswork)

The marbled crayfish is a exotic crayfish in the Netherlands that falls under the recent the European Exotics Regulation (EU 1143/2014) came into effect. There are no populations known to date from the Netherlands (Koese & Soes, 2011; D.M. Soes, unpublished). It is therefore important for the early detection of marbled crayfish in new river branches quickly so that possible measures can be taken to prevent further dissemination or even enable elimination.

In 2014 and 2015 in the west of Middelburg (near Hugo de Grootlaan), two possible marbled crayfish were found. One observation was one dead individual in a firebreak. The second individual was found alive in a garden pond. There is also an undated observation of a living crayfish in the same firebreak. This information was further explained by the NVWA conduct research.

This report describes:
1. the definitive determination of the crayfish found;
2. an inventory of the possible occurrence of the species in the direct environment of the findings;
3. the chances of spreading if they are in the west of Middelburg.

14 August 2018

Marenkov and colleagues, 2018

Marenkov O, Prychepa M, Kovalchuk J. 2018. The influence of heavy metal ions on the viability and metabolic enzyme activity of the marbled crayfish Procambarus virginalis (Lyko, 2017). International Letters of Natural Sciences 70: 11-23. https://doi.org/10.18052/www.scipress.com/ILNS.70.11


The article shows the results of studies on the influence of heavy metal ions (manganese, nickel, lead) on the viability and metabolic enzyme activity of marbled crayfish Procambarus virginalis (Lyko, 2017) (Decapoda). Due to the fact that marbled crayfish got into the reservoirs of the Dnipropetrovsk region in 2015, it was necessary to study the possibilities of its adaptation to environmental factors of reservoirs for further prediction of its distribution or even acclimatization under conditions of toxicological contamination of the ponds of the steppe Prydniprovya. In the
experiment with marbled crayfish, chronic effects of various concentrations of heavy metal ions on the physiological state and enzyme activity were investigated. The obtained results showed that
among the investigated heavy metals nickel ions influenced the weight indexes and mortality of crustaceans the most negatively. According to the results of the research, significant changes were
noted in the individual biochemical parameters of marbled crayfish under the influence of manganese, lead and nickel ions. The most significant changes in the activity of lactate dehydrogenase were detected in muscle tissues affected by manganese and nickel ions. A significant decrease in the activity of succinate dehydrogenase in muscle of marbled crayfish was determined after the action of heavy metal ions. Investigation of changes in the activity of alkaline phosphatase under the influence of the ions of manganese, lead and nickel has its own characteristics, which indicates certain violations in the tissues of cell membranes. Changes in the activity of enzymes were also reflected in the overall protein content. In conclusion, changes in these parameters may indicate a rapid biochemical response of crustaceans to the toxic effects of heavy metals.

Keywords: manganese • nickel • lead • crustaceans • Procambarus virginalis • succinate • dehydrogenase • lactate dehydrogenase • alkaline phosphatase

04 August 2018

"Say my name, say my name": The Guardian podcast

Marmorkrebs make an appearance in the Guardian's Science Weekly podcast as part of a discussion about naming species. If you're super directed, the marbled crayfish discussion with Tim Cockerill starts about 7 minutes in (07:20, to be exact).

This podcast raises a question for me, though. What is the preferred pronunciation of “slough”? As in Procambarus fallax, the slough crayfish? The podcast presenter, Graihagh Jackson, has it rhyme with “cow.” I’ve always pronounced with to rhyme with “you.” As this post notes, words ending in "-ough" have a bewildering number of sounds.

External links

Tricky taxonomy: the problems with naming new species