The crayfish / crawfish / crawdad war

Business Insider features this heat map of what people call crayfish in the United States. It’s all very confusing.

First, the question asks what people call “miniature lobsters”. I’m not sure that’s helpful. Do you have any idea how many kinds of crustaceans are called “lobsters”? There are clawed lobsters, spiny lobsters, slipper lobsters, squat lobsters...

Second, I’m particularly puzzled by people use “crawdad.” Not that they do, but that there are two disconnected blobs of green. I would have expected more continuity.

Maybe Americans should follow the lead of the Australians and call them all “yabbies.”

Hat tip to P.Z. Myers.

External links

22 Maps That Show How Americans Speak English Totally Differently From Each Other
It’s “crawdads”!

Crayfiction

Sometimes, a druid’s just got to catch some crayfish.

In this short story by Kevin Hearne, “A Test of Mettle,” druid initiate Granuaile MacTiernan is tasked with controlling invasive crayfish:

With Sonora’s guidance, sensed through the turquoise sphere at the base of my throat, I can feel the flow of water there, feel the gentle slowness under the rock, the place where a large crawdad has made its home. A crawdad from the Midwest that doesn’t belong on this side of the continental divide, an invasive species that’s been killing off the native fish by eating their eggs. Elementary school kids dumped them in here at the end of their crustacean unit, and their teachers, who should have known better, let them ravage an ecosystem in the process.

This story, and some others, is available for free from Kevin’s website. Thanks, Kevin, for bringing crayfish to art!

External links

Kevin Hearne: Short Stories
Kevin Hearne on Twitter

The Ecdysiast feature

The newest issue of The Crustacean Society’s newsletter, The Ecdysiast, is now available for viewing here. There are several articles of interest for readers. One is coverage of the SICB crayfish symposium that occurred in January It includes a note of the untimely death of Francesca Gherardi.

Also of interest are articles by Fred Schram, the general editor for the Journal of Crustacean Biology. In particular, “To be open or not to be open: That is the question” (page 7) is a look at open access from the perspective of someone in the thick of trying to maintain a journal in the face of a changing market, which includes declining Society membership.

Is OA the wave of the future? – maybe. However, we might suggest that “efficient” application of the OA model will lead to the collapse of many journals, especially those produced by small scholarly societies.

(Plug: If you are interested in crustacean biology, you should join the Society!)

“Your heart stops”: Marmorkrebs in Scotland

Scotsman.com reports on the seizure of Marmorkrebs in the Central Belt.

Dr Colin Bean, science and policy advisor on freshwater biology at Scottish Natural Heritage, formally identified the recovered species in the current case.

He said: “Your heart stops really because American signal are bad enough. The biggest difference between marbled crayfish and other crayfish species is that the others need a male and a female to reproduce, but marbled crayfish are parthenogenic [reproduce asexually] which means you only need one to establish a population.

Yet again, these were Marmorkrebs sold through the pet trade. Kudos to the Scots for taking the task of monitoring exotics seriously:

Anyone caught in possession of non-native crayfish in Scotland can be jailed for up to six months and fined £40,000.

Some species distribution models suggest Scotland could be suitable habitat for Marmorkrebs. At right is an excerpt from Figure 3D in Feria and Faulkes (2011). There are three other models in that figure, and the other three predict much less habitat. Given the number of Marmorkrebs found in Europe since that paper was prepared, though, this version is probably the better reflection of the possible suitable habitat than the others.

Lastly, I appreciate that the news article carries on the European tabloid tradition of referring to small crayfish with monster movie descriptions, calling Marmorkrebs:

A voracious alien predator

Well, most crayfish do catch and eat other animals... but predator? Not what you would usually use to describe an omnivore that eats snails and other small benthic invertebrates.

External link

Scots wildlife at risk from alien crayfish breeds

Reference

Feria TP, Faulkes Z. 2011. Forecasting the distribution of Marmorkrebs, a parthenogenetic crayfish with high invasive potential, in Madagascar, Europe, and North America. Aquatic Invasions 6(1): 55-67. http://dx.doi.org/10.3391/ai.2011.6.1.07

A third parthenogenetic crayfish species?

Probably not. This passage in a new paper by Rogowski and colleagues about the virile crayfish (Orconectes virilis; right) is interesting, however:

An interesting observation in the laboratory was the production of eggs and juveniles by a female that was collected in July and kept in isolation. This would suggest that females can maintain viable sperm for an extended period, potentially over 1 year (Reynolds, 2002), or that they will produce viable eggs even if they are not fertilised. Other crayfish have been known to reproduce clonally, for example Orconectes limosus (Buřič et al., 2011) and the marbled crayfish Procambarus fallax (Scholtz et al., 2003). Whether this individual maintained sperm from a previous mating or whether it was parthenogenetic is unknown.

If I were to bet, I would bet on sperm storage, which so many arthropods can do. While the evidence for Orconectes limosus being a facultative parthenogen is quite solid, even that has yet to be replicated. Either way, there seems to be much more work necessary to distinguish these two scenarios.

Reference

Rogowski DL, Sitko S, Bonar SA. Optimising control of invasive crayfish using life-history information. Freshwater Biology. in press. http://dx.doi.org/10.1111/fwb.12126

Calming

Faulkes, 2013

Faulkes Z. 2012. How much is that crayfish in the window? Online monitoring of Marmorkrebs, Procambarus fallax f. virginalis (Hagen, 1870) in the North American pet trade. Freshwater Crayfish 19(1): 39-44. http://dx.doi.org/10.5869/fc.2013.v19.039

Abstract

Marmorkrebs were discovered by European pet owners in the 1990s. Because there is no known native population of Marmorkrebs, the distribution of these crayfish is purely the result of human activity. Marmorkrebs are now spread throughout the pet trade worldwide and are introduced species in several countries. Given that the pet trade has been the suspected or confirmed source of introduction of many introduced species, I monitored online social activity for information about the use and spread of Marmorkrebs in North America. This revealed several new jurisdictions where Marmorkrebs had not been previously reported. Several records were found in jurisdictions where the local laws prohibited the owners from having Marmorkrebs. Tracking such records could be useful in determining the risk of Marmorkrebs introductions from release by pet owners.

Keywords: marbled crayfish • pet trade