27 April 2020

False alarm! There are no Marmorkrebs loose in Canada (that we know of)

There are no Marmorkrebs in Alberta. Well, there are no Marmorkrebs in the wild in Alberta.

After reading this article claiming marbled crayfish had been found in Alberta for years, I reached out to interviewee Nichol Kimmel at Alberta Environment and Parks for more details.

She wrote that the article replaced “Northern crayfish” (also known as the virile crayfish, or Faxonius virilis, formerly known as Orconectes virilis) with “marbled crayfish.” Furthermore, Environment and Parks does not know of any released locations of Marmorkrebs.

This would explain why B.W. Williams, who has extensive knowledge of Canadian crayfish, looked at the article and tweeted:

Right, but most of their photos in that article are of Faxonius virilis, which has spread on its own (expedited postglacial expansion) in many rivers of Alberta; and by bait bucket dumps in portions of the upper South Saskatchewan River (including Bow).

I have removed the Alberta entries in the map of Marmorkrebs introductions.

Related posts

Canadian Marmorkrebs: The North American invasion has begun

External links

This self-cloning crayfish is scuttling into rivers and streams throughout Alberta

25 April 2020

Talasu 2020

Talasu S. 2020. Identifying dopamine receptor genes and transcription marbled crayfish. Presentation given to Illinois Mathematics and Science Academy, 22 April 2020. https://digitalcommons.imsa.edu/sir_presentations/2020/session1/76/


Modulatory transmitters are major contributors to nervous system plasticity and behavioral flexibility, they determine motivational states and are involved in psychiatric and neurological disorders. Neuromodulators act through distinct receptors and the diversity in receptor subtypes and distribution allows a single neuromodulator can exert many different actions. A prerequisite to understand the ways modulators work is to identify which receptors are expressed in an animal.

I studied which Dopamine receptors are present in the Procambarus virginalis also known as Marbled Crayfish, a highly invasive female species with high quality genome and transcriptomes. Their broad behavioral repertoire makes them ideal for studying the actions of neuromodulator receptors. We focused on Dopamine receptors as they play a role in Parkinson’s disease and the reward system of vertebrates and invertebrates.

Using bioinformatics, we identified which dopamine receptors (D2Alpha and D2beta) exist in marbled crayfish. After identifying homologs of both receptors, a conserved domains search revealed no direct functional domains for these putative D2alpha and D2beta receptors. PCR with D2alpha primers on ventral nerve cord mRNA further revealed that this putative receptor is notexpressed in the marbled crayfish nervous system. We are currently testing the expression of D2beta in in the ventral nerve cord.

Keywords: None provided.

24 April 2020

Marmorkrebs are illegal in Idaho

While doing some updates related to the announcement that Marmorkrebs are apparently all over the place in Alberta, I stumbled upon legislation that I was unaware of.

In Idaho, Marmorkrebs is designated “Aquatic Invertebrate Invasive Species” (AIIS). So says the IDAPA 02.06.09 “Rules Governing Invasive Species and Noxious Weeds.” In fact, they are so worried about it that it is listed twice in the current regulations: once as “Marbled Crayfish (Procambarus marmorkrebs)” (sic) and once as “Marmorkrebs Procambarus sp.” (Section 140).

As an invasive species, Idaho says, “No person may possess, cultivate, import, ship, or transport any invasive species.” Unless, that is, you want to eat them. If you want to eat crayfish, you need a permit.

Trying to find when Marmorkrebs was added to this list was difficult, but it seems to have been way back in 2010, based on this administrative bulletin (PDF).

I continue to be extraordinarily frustrated by how hard it is to finding regulations about crayfish on a state to state and province to province level. This law was passed at which this website and blog was already a few years old. Yet it took me a decade to discover this law, even when I keep a specific look out for anything Marmorkrebs related, with Google alerts and more.

I’m reminded of Douglas Adams’s description of what bureaucrats consider “public notice.”

“But the plans were on display…”

“On display? I eventually had to go down to the cellar to find them.”

“That’s the display department.”

“With a flashlight.”

“Ah, well, the lights had probably gone.”

“So had the stairs.”

“But look, you found the notice, didn’t you?”

“Yes,” said Arthur, “yes I did. It was on display in the bottom of a locked filing cabinet stuck in a disused lavatory with a sign on the door saying ‘Beware of the Leopard.’”

From The Hitchhiker’s Guide to the Galaxy, of course.

External links

Marbled crayfish / Marmorkrebs fact sheet (PDF)
Invasive species of Idaho
IDAPA 02.06.09, Rules Governing Invasive Species and Noxious Weeds (PDF)
Idaho Administrative Bulletin, Volume 10-1 (PDF)

Canadian Marmorkrebs: The North American invasion has begun

Update, 24 April 2020: The CBC news article was wrong. There are no Marmorkrebs in the wild in Canada. See this follow-up post.

I have been wondering for years when I would hear the first confirmed reports of marbled crayfish in the wild in North American, and today is the day.

The Canadian Broadcasting Company (CBC) is reporting not only that Marmorkrebs are in the province of Alberta, but they have apparently been there for some time.

In the last 10 to 20 years however, the marbled crayfish — a crustacean not native to the Bow River — has begun spreading to rivers and lakes throughout Alberta.

It's a problem that Nicole Kimmel, aquatic invasive species specialist for Alberta Environment and Parks, is trying to tackle.

Historically, the crustaceans are normally found in between Wainwright and Ryley in the Beaver River watershed south of Edmonton, Kimmel told The Calgary Eyeopener.

But now they’ve been showing up in water bodies anywhere from the Edmonton area, down to Calgary and Medicine Hat, as well as in the Milk River region.

I’m gobsmacked that marbled crayfish have apparently been out in Alberta for years in multiple locations but that this information apparently never made it out of Alberta, never mind into the scientific literature.

And yet again, people put out origin stories for Marmorkrebs that are not supported by evidence.

Kimmel calls the marbled crayfish a kind of “freak accident” of two crayfish species that may have been imported from Florida into Germany in the ‘90s and were able to mate.

There is no evidence that Marmorkrebs were created by hybridization.

I’ll be following up with the province and seeing if I can discover more. I have not updated the map of Marmorkrebs introductions, but should do soon.

Update: The map of Marmorkrebs introductions now contains general Alberta locations.

External links

This self-cloning crayfish is scuttling into rivers and streams throughout Alberta

23 April 2020

Laurenz and colleagues 2020

Laurenz J, Georg A, Brendelberger H, Lehmann K. 2020. Effects of nitrate on early life stages of Astacus astacus (Linnaeus, 1758) and Procambarus virginalis (Lyko, 2017). International Aquatic Research 12(1): 53-62. https://doi.org/10.22034/iar(20).2020.671232


We examined the effects of nitrate on the embryonic development of two freshwater crayfish species, the indigenous noble crayfish (Astacus astacus) and the invasive marbled crayfish (Procambarus virginalis). Nitrate measurements show concentrations of 50 mg/L in surface waters of Germany, while concentrations in groundwater measure up to 100 mg/L. Performing a chronic exposure experiment, we exposed embryos of both species to nitrate concentrations of between 0.0 mg/L and 500 mg/L to estimate the influences of nitrate concentrations on survival, hatching development time, malformations and growth. We observed the first effects on survival at 14 mg/L LOEC (lowest observed effective concentration) nitrate for marbled crayfish. For noble crayfish, we estimated an EC50 value of 55.7 mg/L on hatching rate. Our results show that eutrophication of surface waters can negatively affect the embryonic development of freshwater crayfish with serious consequences on recruitment.

Keywords: marbled crayfish • noble crayfish • juveniles • nitrate • embryonic

17 April 2020

Michigan considering prohibiting Marmorkrebs

Yesterday, there was a conference call meeting of the Michigan Natural Resources Commission that included discussion of adding Marmorkrebs to the state’s list of invasive species.

The presentation slide deck makes some... interesting statements.

Slide 14 in the deck says, “No native range, presumed product of captive breeding”. This implies that someone deliberately set out to create an asexual crayfish, and that’s misleading at best. There is zero evidence I am aware of that anyone deliberately set out to create an asexual crayfish. Marmorkrebs may have originated in captivity, but nobody planned it. Nobody thought an asexual crayfish was even possible. Nobody was “breeding” for it

Slide 15 says, “Threat to natural resources: Aggressive behavior traits”. This is an odd item to list first. There is no evidence that Marmorkrebs are more aggressive than other crayfish species. The papers on Marmorkrebs fighting to date have shown that they are competitive in when they are facing size-matched individuals from other species. The qualifier is important, because Marmokrebs are smallish crayfish. Many other species get larger, and large animals win. Further, Marmorkrebs have only been compared with a couple of other crayfish species.

The same slide lists another threat as “Introduce disease”. Maybe? Disease has been a big problem with introduced crayfish in Europe, but last I looked at a map, Michigan is not Europe. In the US, disease has usually not been a significant problem with crayfish impacts. It could be. But so far, this seems like one of the lower risks.

I would have inverted this list, and started with “Alter fish communities” and “Degrade water quality”.

The bottom line? The slide deck lists the “next steps” as:
  • Recommend listing Marbled Crayfish as prohibited to DNR-Director
  • Officially list in May, if recommendation is approved
So this process looks quite advanced and likely to happen.

If this went through, this would make Michgan the third North American jurisdiction to regulate Marmorkrebs specifically.

External links

16 April 2020 agenda of Natural Resource Commission (PDF)
Presentations given to the NRC - 16 April 2020, Fish (PDF)

Join in this week’s NRC meeting online or by conference call

16 April 2020

Andriantsoa and colleagues, 2020

Andriantsoa R, Jones JPG, Achimescu V, Randrianarison H, Raselimanana M, Andriatsitohaina M, Rasamy J, Lyko F. 2020. Perceived socio-economic impacts of the marbled crayfish invasion in Madagascar. PLOS ONE 15(4): e0231773. https://doi.org/10.1371/journal.pone.0231773

The negative environmental and economic impacts of many invasive species are well known. However, given the increased homogenization of global biota, and the difficulty of eradicating species once established, a balanced approach to considering the impacts of invasive species is needed. The marbled crayfish (Procambarus virginalis) is a parthenogenetic freshwater crayfish that was first observed in Madagascar around 2005 and has spread rapidly. We present the results of a socio-economic survey (n = 385) in three regions of Madagascar that vary in terms of when the marbled crayfish first arrived. Respondents generally considered marbled crayfish to have a negative impact on rice agriculture and fishing, however the animals were seen as making a positive contribution to household economy and food security. Regression modeling showed that respondents in regions with longer experience of marbled crayfish have more positive perceptions. Unsurprisingly, considering the perception that crayfish negatively impact rice agriculture, those not involved in crayfish harvesting and trading had more negative views towards the crayfish than those involved in crayfish-related activities. Food preference ranking and market surveys revealed the acceptance of marbled crayfish as a cheap source of animal protein; a clear positive in a country with widespread malnutrition. While data on biodiversity impacts of the marbled crayfish invasion in Madagascar are still completely lacking, this study provides insight into the socio-economic impacts of the dramatic spread of this unique invasive species. “Biby kely tsy fantam-piaviana, mahavelona fianakaviana” (a small animal coming from who knows where which supports the needs of the family). Government worker Analamanga, Madagascar.

Keywords: None provided.

Note: Co-author Julia Jones provides a summary of this paper and some personal commentary in a Twitter thread. Excerpt:

Fozaorana (Procambarus virginalis to give them their scientific name) became synonymous in Malagasy with something cheap and poor quality. Cheap burner phones are called fozaorana for example. ... (O)ur recent paper shows that (especially in areas which have been invaded longer), people tend to quite appreciate the crayfish & feel they make a positive impact in food security and livelihoods.

09 April 2020

Coronavirus cancels crayfish conference

This year’s International Association of Astacology conference is not happening, due to COVID-19 concerns. The next meeting is scheduled for 2021.

(I should say, “tentatively scheduled,” since we don’t know how long this pandemic is going to go on.)