27 July 2010

North American crayfish diversity threatened

ResearchBlogging.orgWhen I recently attended the International Association of Astacology meeting, it was ground into my face how bad things are for crayfish.

In Europe, crayfish are being beaten up by exotic North American species. If competition doesn’t get them, the crayfish plague that the exotics carry will.

In North America, the home to the greatest diversity of crayfish species in the world, non-indigenous species are playing a role in some regions, but habitat degradation is the bigger concern. At the Astacology meeting, we were treated to scenes like this:

Mountains are being flattened to remove coal.

Strangely, the same factors that lead to the wonderful high diversity of North American crayfish are the same factors that make them vulnerable, mainly geographic isolation. Because crayfish need to stay wet, and are not terribly mobile, they often don’t disperse very well on their own. Consequently, many species have a limited range, often falling within a few locations in a single American state.

Taylor and colleagues provide a summary of just how bad things are in North America. The take home message that every crayfish biologist and every crayfish pet owner should have burned into their brain is this:

Almost half of North American crayfish species are under threat.

I don’t use the phrase “under threat” in any sort of technical way, but just indicating some sort of conservation concern.

On a per species basis, crayfish are the second third most threatened kind of animal in North America, behind freshwater mussels and snails, which obviously have many of the same issues as crayfish: small geographic ranges, limited mobility (though crayfish are more mobile than snails and mussels), vulnerable to competition and habitat degradation.

Taylor and colleagues provide other useful information, including a list of all known species and a standard common name. The article is rather nicely illustrated with a few crayfish pictures, too (not for every species, however).

All of this makes the prospect of Marmorkrebs being introduced into North American waters a veritable nightmare scenario. Competition between Marmorkrebs and a local species could be enough to push a species into extinction.


Taylor, C., Schuster, G., Cooper, J., DiStefano, R., Eversole, A., Hamr, P., Hobbs, III, H., Robison, H., Skelton, C., & Thoma, R. (2007). A Reassessment of the Conservation Status of Crayfishes of the United States and Canada after 10+ Years of Increased Awareness Fisheries 32(8): 372-389. DOI: 10.1577/1548-8446(2007)32[372:AROTCS]2.0.CO;2

Photo by ddimick on Flickr. Used under a Creative Commons license.

24 July 2010

18th International Association of Astacology conference: Day 5

On the last day of the conference, everyone’s ready to go, having had enough of the undergrad food and residence rooms. But everyone is sad that they probably won’t be seeing some of their friends, old and new, for some time.

Impressions: Gatorade for breakfast. There is a blue crab genome project, and maybe a crayfish one. Some Engaewa burrowing crayfish look amazingly like thalassindean mud shrimp; I badly want to look at their neurons.

After the last few talks, there was a brief meeting announcing the award for best talk and best poster came out; congratulations to the four winners. The winners for the talks were David Strand in the student category and Jim Stoeckel for the professional category. (Alas, I cannot recall the poster winners. Something I ate didn't agree with me, and I was rather queasy right when they gave those awards. I didn't have the presence of mind to write down all the names.) For the record: A singing voice and Prezi is not a winning formula for a best presentation award. Congratulations to the winners.

Catherine Souty-Grosset, who had left before they tried to give her an award at last night's banquet, was present and received her award this time. They also handed over the “keys to the car” for the new president of the association, which includes a fossil crayfish. The fossil crayfish is kept by the I.A.A. president, held in a box guaranteed for life except against:

  1. Shark bites
  2. Small children

It was pointed out the incoming president Jim Fetzner (pictured above) has at least one of those.

Conference organizer Annie Allert is nicknamed “The General” for her organizational skills, but even The General succumbed at the end of the meeting, and it was touching to hear her voice when she told the delegates that they have friends in Missouri. So one last time, I salute The General and all the other organizers and delegates who made my first visit to the conference an enjoyable one.

Austria in 2012!

22 July 2010

18th International Association of Astacology conference: Day 4

The audience for talks is thinning out a bit, and so are the speakers. Two cancellations in the scheduled presentations today.

Impressions: As far as Louisiana crayfishermen are concerned, do anything you want – except pass any legislation; crayfish plague is not a fungus, but some weird phylum that I've never heard of before; porcelain disease has a pretty name but a bad effect on crayfish; IAA 19 will be in Austria for the 40th anniversary.

There are still more talks tomorrow morning, but this evening had a bit of a closing feel to it at the conference banquet. Drinks, food, music, some serious awards (career awards for Alistair Richardson and Francesca Gherhardi), and some silly awards. Delivered by a man with claws and the Crawdettes.

One award managed to combine silly and serious. Abbie came to the conference from England, and had her luggage completely lost. She's been wearing the same clothes all week. So the I.A.A. gave her a princess costume, which she is twirling in here:

Others went to the Blue Note to listen to blues. I, alas, reached the limit of how much I can do on five hours of sleep a night, so came back early.

The Flickr photostream continues to lengthen.

P.S. – My talk? The audience learned that to the tune of this:

You can sing this:

Super cloning crayfish team Marmorkrebs go!
Super cloning crayfish team Marmorkrebs go!
If you need a crayfish that's a name you should know
Super cloning crayfish team Marmorkrebs go!

And for those of you asking how I did my talk, it was made with Prezi.

21 July 2010

18th International Association of Astacology conference: Day 3

Field trip! Most of the astacologists went to the Shaw Nature Reserve today. It’s a long drive there, the temperature was probably in the high 30s C, and the humidity was probably in the high 90s.

But look at this little guy!

Going on a field walk with a bunch of astacologists is interesting. Quinton, with the classic, “I’ll have a go” Australian attitude, saw some chimneys of crayfish burrows under a footbridge, got down and got his hand nearly up to his elbow to retrieve this one. Still a juvenile, couldn't be sexed.

I said, “$5 to whoever can identify the species,” but had no takers. So still not sure myself what species this is.

At another end of the reserve, this was the only crayfish I saw, in Bascom House:

Additional: I have since heard that the burrower in the video above may be Cambarus diogenes.

20 July 2010

18th International Association of Astacology conference: Day 2

7:16 am: Oh dear. This is what you get for not paying attention. I heard something outside my room, looked out, and say a tree being whipped around quite heavily by wind.

Then the rain started. Soon followed by thunder and lightning.

Long range forecasts indicated mostly fine weather, so I had no umbrella or even a jacket. Luckily, my room and the life sciences building are very close. Still, I think I'm going to get wet today.

8:41 pm: Luckily, the rain stopped slowed by the time I walked to the sessions, stopped most of the day, and was just starting to drizzle after the poster session ended. I'm glad I didn't walk downtown to the pub, but otherwise, lucky.

I think even the few participants in the ungodly hour fun run managed to avoid the soaking (they were running at 6:00 am or something similarly crazy).

A few impressions from today:

Kids love crayfish, and are some of our best allies; the biggest crayfish in the world probably lives decades but not centuries; meeting another Marmorkrebs author, Tadashi Kawai; a beautiful talk about garbage; getting introduced to the first new crayfish species in a decade (and a big one); 53% of American crayfish species are imperiled, which is one of the highest values for any North American group.

Word of the day: Trogloxene, (n.): An organism that is associated with caves, but can't live its entire life in caves. E.g., bats.

Photo gallery for the meeting continues to expand here.

18th International Association of Astacology conference: Day 1

Today: Invasive species, "You're the marbled man," mini-muffins, more invasive crayfish, brownies, trying to turn Freshwater Crayfish into a journal you'd want to publish in, U.S. Geological Survey station tour (pictured), Flat Branch Pub and Brewing, momentarily being locked out of the residence building because I was out to late.

It's late and I'm tired, so I'll just direct you to some more photos, such as they are.

18 July 2010

18th International Association of Astacology conference: Day 0

The day started off with me discovering that my flight would be departing about 45 minutes later than planned when I booked it. Fairly high chance I’ll miss my connecting flight, but the alternative was a much, much later flight, so I decided to risk it.

The risk paid off. The plane we arrived just in time for me to walk across to a nearby gate and board my connecting flight. As I was walking toward the gate, the staffer said, "Faulkes?" They knew I was coming, and I was literally the last to board the plane.

The Columbia airport is small (and if you've ever seen the McAllen airport I left from, you know that's saying something.) This turned out to be beneficial, though, when a man walked into the lobby and asked, "Is anyone else going to the University of Maryland?"

Clearly, it was up to me to help this poor unfortunate soul, since he was unlikely to find it easy to get to the University of Maryland after having just landed in Missouri.

Jay and I agreed to split a cab to the University of Missouri, but he had a story that made his momentary lapse of geography look trivial. Apparently, someone on his plane was supposed to go to St. Louis, not Columbia. My first thought was, "Isn't that what boarding passes are supposed to prevent?"

The University of Missouri campus is green and smells nice. I'm not sure it'll smell as nice tomorrow, because there's a lot of construction going on, which was stopped today. Got checked into my room and made my way to Jesse Hall for the opening reception.

After having no lunch today because of the super fast layover, plus walking around a bit in the heat, I was famished and was starting to get a slight headache around the time I checked in. Fortunately, both problems were soon solved. They laid out some really excellent barbecued pulled pork and beef, coleslaw, and some fruit cobblers for desert. I was quite full by the end.

Tomorrow, the science presentations start in the Christopher S. Bond Life Science Building, which appears to be rather new. Even in twilight, it almost loks like it's glistening a bit.

Marmorkrebs conversations so far: When I mentioned, "I know what I'm working with, but it has no species name," "The self-cloning ones?" was the immediate reply. Also got a comment that they were all through the pet trade, which is kind of the topic of my next paper.

P.S. – Any campus that has baby bunnies wandering around it has my approval.

13 July 2010

Asexual species identifications

ResearchBlogging.orgMarmorkrebs are difficult beasts. As I’ve mentioned before, there is no species name for them yet, partly because of how people define species. At the practical level, most crayfish are identified by the sex organs of the males (which Marmorkrebs don’t have). At the conceptual level, many people define species by interbreeding populations (which parthenogenetic organisms don’t do).

Birky and colleagues recently proposed a way to define species for parthenogenetic organisms. As near as I can understand it, their argument runs like this.

First, they’re going to define species using DNA. They just think morphology is too subtle and too prone to mislead.

Second, the criteria that they’re going to use to separate species is going to revolve around two key concepts: genetic drift and adaptation to a niche.

For any organism, even parthenogenetic clones like Marmorkrebs, there is a certain probability that mutations will occur each generation. Even when there is no selection pressure for that mutation, the frequency of the mutation in the population will change just due to chance over time, even becoming fixed or eliminated. That’s genetic drift.

Birky and company define a species as a group of organisms that show genetic changes that are too large to be accounted for by drift alone. They argue that this is indicative of a population that has undergone adaptation to a specific ecological niche.

The details of their proposal involve a fair amount of math, which, for the purposes of writing a blog post, I didn’t feel the need to become intimately acquainted with. At first glance, however, this approach seems generally fruitful. They apply their methods to six different asexual groups, and seem to make some headway on defining them. I think they could also apply their approach to sorting defining an asexual species that is derived from sexual ancestors, although they don’t discuss this.

Some potential glitches in their approach are that they effectively rule out the possibility that two species could be created by drift alone, which I think many evolutionary biologist would be uncomfortable with. They also mention briefly the idea of “higher taxa,” but how to define those higher taxa was not laid out nearly as clearly as for species.

But they do provide hope that Marmorkrebs, and many other asexuals, can get recognized as species, as they should be, in my opinion.


Birky C, Adams J, Gemmel M, & Perry J. 2010. Using population genetic theory and DNA sequences for species detection and identification in asexual organisms PLoS ONE 5(5): e10609. DOI: 10.1371/journal.pone.0010609

07 July 2010

Marmorkrebs continue their rise in Germany

Peay S. 2009. Invasive non-indigenous crayfish species in Europe: Recommendations on managing them. Knowledge and Management of Aquatic Ecosystems 394-395: 3. http://dx.doi.org/10.1051/kmae/2010009

This paper contains a couple of mentions about Marmorkrebs (though they are so brief that doesn’t quite rate a separate entry in the abstracts). The most important one is this:

At least three new populations of marbled crayfish Procambarus sp. have been found in the wild in Germany in the past two years, all aquarium discards (Chucholl, pers. comm.).

“Chucholl” is Chris Chucholl, who is studying ecology and invasive species issues.

06 July 2010

Holdich and colleagues, 2010

Holdich DM, Reynolds JD, Souty-Grosset C, Sibley PJ. 2010. A review of the ever increasing threat to European crayfish from non-indigenous crayfish species. Knowledge and Management of Aquatic Ecosystems 394-395: 11. http://dx.doi.org/10.1051/kmae/2009025

Non-indigenous crayfish species (NICS) in Europe now outnumber indigenous crayfish species (ICS) 2:1, and it has been predicted that they may dominate completely in the next few decades unless something is done to protect them. Of the ten NICS introduced at least nine have become established in areas occupied by four of the five ICS. A decline in stocks of ICS has been recorded in many countries in the face of increasing populations of NICS. Most European countries retain at least one ICS but all are under threat from habitat loss, deteriorating water quality, overfishing, climate change, and most importantly from NICS and crayfish plague. The threat to ICS is so great in some countries that “ark” sanctuary sites are being established.

The three most widely-spread NICS are the North American species: Pacifastacus leniusculus, Orconectes limosus and Procambarus clarkii. These can be considered as “Old NICS”, which were introduced before 1975, compared with the “New NICS”, which were introduced after 1980, such as the North American species: Orconectes immunis, Orconectes juvenilis, Orconectes virilis, Procambarus sp. and Procambarus acutus; and the Australian species: Cherax destructor and Cherax quadricarinatus, all of which have much narrower ranges in Europe. The North American species are potentially capable of acting as vectors of crayfish plague. Outbreaks of this disease occur regularly where there are high concentrations of vectors.

In addition to the NICS currently established in the wild, a further threat exists through the aquarium trade, where many American and Australian species are available via the internet and in aquarist centres. Owners of such species may discard them into the freshwater environment when they grow too big as with some Cherax spp. and Orconectes spp., or multiply too frequently as with Procambarus sp. (a parthenogenetic species). A conceptual model is presented as a possible way forward for protecting the future survival of ICS in Europe.

Keywords: None provided.

05 July 2010

On their way

My cup runneth over. I’ve just updated the home page and the list of research papers with references to three five exciting new Marmorkrebs papers that are now in press.

A preprint of one is available now. The abstracts will join the compilation here on the blog when the final, paginated versions are published.

Additional: Two more papers added on 8 July 2010.

01 July 2010

The problem with a coup détat

Madagascar is now home to one of the world's "unsupervised" Marmorkrebs populations. But, as I've noted before, the place is a political mess. The political mess has spilled over into a conservation mess.

That's the problem with a coup détat: Everyone assumes they can literally take anything they want.

That quote is from primatologist Patricia Wright. In this detailed interview, she lays out the current state of the situation in all its complexity.