Being chilly today, I did something I like to do on such days, watched the WPB Manatee Lagoon live manatee cam. As I tuned in there was a manatee unusually close to the underwater camera, presenting a view new to my experience:   a submerged live close-up of manatee skin and associated fishy business.

Seen from a little distance manatees always seem to wear a lot of algae and other tagalongs. But seeing it up close was eye-opening in two ways:

1. A lot of the algae is not green, slimy, or stringy, but rather little rusty-brownish tufts on some but not all manatees.
2. Swarms of tiny fish hover around some of the mighty beasts expressing interest  in manatee skin and what’s on it.

Now…I’m no expert on manatee dermatology, but a little Googling turned up novel fun. No need for a blog anymore!  AI is an instant blog on demand.   Replaced by the machine!?  Despite that impending complication, the brownish algal tufts perhaps-to-probably belong to one or more of three species of red algae (not red tide)  described since 2019 by biologists Karen Woodworth, D.W. Freshwater,  and colleagues  as manatee skin dwellers. The fist-known of the three is Melanothamnus maniticola. (Manticola means roughly “lives on manatees.”)

Photo by NOAA on Unsplash

As the algal discoverers pointed out, the alga and the manatee are a match made in heaven.  Although unproven, it seems the manatee may benefit from the algae as “sunscreen.”   And the algae have several adaptations to wastin’ away again in manatee-ville, especially a system of little “fingers” to cling to the rough skin.   The algae are extra-tough, which helps when attached to a submarine that brushes against other submarines, weeds, and logs.    Manatees have also “their own” species of barnacle  too, Chelonibia manati.  The barnacle cruises on its free ride trawling for detritus. Not well checked out, it probably enjoys first dibs on shedding manatee skin and other manatee-debree.

Yet another recently discovered unique manatee-rider gets in on the bounty.  The diatom (broadly speaking a type of microscopic algae) Tursiocola gracilis, discovered in 2015 by T. Frankovich and colleagues, behaves in a most-unplantlike fashion. It performs no photosynthesis. Rather, somehow it derives nutrition from dead manatee skin and/or microbial life on it.  The abundant diatoms are thought perhaps to suppress harmful microbes on the grateful manatee’s hide.

Fish cleaning manatees are pretty well known, extending to multiple species of fish, picking off algae, parasites, and shed skin.   They are presumably mostly beneficial, except for one annoyingly overzealous invasive catfish species.

In this video you can see the picky little fish. (The intense swarm toward the bottom of the video is bubbles.)

https://drive.google.com/file/d/14BmVy5l4-GFrKWpIdfkJ0yeZ-q4PZlyJ/view?usp=drive_link

Sure hope 2026 is a good year to be a manatee!

Extra things:

https://onlinelibrary.wiley.com/doi/10.1111/jpy.12912

https://www.researchgate.net/publication/340082479_For_Better_For_Worse_Manatee-Associated_Tursiocola_Bacillariophyta_Remain_Faithful_to_Their_Host