Always nice to stumble across a video mentioning marbled crayfish. I’m kind of used to them showing some other random crayfish species, but this one has a new thing that made me pause.
This video is titled, “This guy copies himself 2,000 times!”
Since marbled crayfish are all female, a better title would be, “This gal copies herself 2,000 times.”
An interesting paper by Park and Jeon (2023) mentioned that South Korea imports about 78,000 crayfish as pets a year from 2018 to 2022. They describe 34 species imported.
I was surprised to see that marbled crayfish are not one of those species listed as being in the Korean pet trade at all. Usually they would be not only widely available, but one of the highest risk species.
But this YouTube video strongly suggests marbled crayfish are available in Korea.
Park Y, Jeon Y. 2023. A study on the import status of pet freshwater crayfish and potential invasive alien species crayfish in Korea. Korean Journal of Ecology and Environment 56(3): 242-249. https://doi.org/10.11614/KSL.2023.56.3.242
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.
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
Marbled Crayfish: From Aquarium Accident to Tanzania's Protein Powerhouse!
The first ten minutes of this video from Great Lakes Now is an excellent mini-documentary on the discovery of Marmorkrebs in North America and steps taken to try to eliminate it.
There’s also a short news article.
Rowan Moore Gerety, author of the excellent Harper’s article on Marmorkrebs in Madagascar, continues his coverage of the story with another outstanding piece. This is an interview with Ranja Andriantsoa.
The article also has a nice video which is one of the best I’ve seen for giving a sense for just how abundant Marmorkrebs are in Madagascar.
External links
The wait is over.
This week, I had a lovely live chat with Dr. Kirsten Sanford, a.k.a. Dr. Kiki on Dr. Kiki’s Science Hour! She titled Episode 110, “Invasion of the Marmorkrebs!”
