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 #4294  by odin
 16 Jan 2018 19:54
An alga parasiting freshwater shrimps
- Pulled from an online website.

To correctly identify the algae that are sent to me, I do a lot of documentary research, and I came across a Japanese paper describing the algae Cladogonium ogishimae, parasitizing the shrimp Neocaridina denticulata. The abstract is in English but the rest of the paper is unfortunately in Japanese, and I do not speak it. Fortunately, another paper entirely in English describes the same parasitic alga on shrimp of the genus Macrobrachium.

Indeed, in recent years we see pictures of shrimps with strange green growths on the pleopods. Over time, the assumed identity of these parasites has evolved. We first thought it was a mushroom, then it was identified as a protozoa ellobiopsidae. The problem is that ellobiopsids are unicellular and very small and the anatomy does not seem to match. On the other hand it fits well with the algae observed by the Japanese.

cladogonium.jpg (102.23 KiB) Viewed 129 times
Pictures extracted from Kazuyo Matsuyama-Serisawa et al.

Surprisingly, this seaweed does not photosynthesize. Unlike other algae it does not have chlorophyll and has no energy reserves in the form of starch. The rest of its anatomy is typical of filamentous algae of the order of cladophorales. But why is it green if there is no chlorophyll? Because although the filamentous alga itself is not photosynthetic, zoospores are. Those mobile zoospores can infect new shrimps.

Knowing that this parasite is a green alga and not a protista ellobiopsidae is important because it will help us to find a targeted treatment, effective and of course, non-toxic for the host shrimp.

In addition: A new ectoparasitic, colorless alga is reported here with the taxonomic description of a new genus and a new species as a member of the Cladophorales. This alga grows on shrimps from Japan. All of the vegetative cells are colorless, but the zoosporangia and the zoospores are furnished with many green chloroplasts.


- A Colorless, Filamentous Chlorophyceous Alga, Cladogonium ogishimae Gen. et Sp. Nov., Parasitic on Fresh-water Shrimps

- Reconfirmation of Cladogonium being ectoparasitic on freshwater shrimp. (Kazuyo Matsuyama-Serisawa et al. 2014)
Halocaridina liked this
 #4634  by Artemis
 13 Mar 2018 11:01
Fascinating! I knew about parasitic plants (usually they parasitise other plants or fungi) but I hadn't heard of an alga that parasitised an animal. Mind you, malaria is a very derived red alga and it's definitive host is an insect so I suppose it isn't unheard of.