When science catches up to the pet trade: Geosesarma crabs
September 24, 2015 7:24 PM   Subscribe

Geosesarma is a genus of small, colorful, land based freshwater crabs, roughly the size of an American quarter. Scientists struggle to properly catalog and describe the varieties of crabs they find in pet stores.

Geosesarma have a small but avid fan club comprised of people from both the exotic pet and aquarium worlds. Hobbyists were surprised to find out that scientists weren't aware of or had not scientifically cataloged at least two species that were well known in the trade. Since Geosesarmas started showing up in the trade about 10 years ago, it has been the norm to actively search out captive bred crabs, but because of the concerns Ng raises in the article, people have become even more motivated to find breeding methods that work well in most hobby situations. The goal is for captive bred animals to become the standard, so no more crabs are collected from the wild for the pet trade. This is similar to the movement one sees in the aquarist community - captive bred animals are considered better adapted to a captive environment, and endure much less stress than wild caught specimens that are then shipped thousands of miles. In addition, people feel better knowing they are not contributing to the depletion of possibly threatened wild populations. I see many similarities between this and the work done 1-2 decades ago to standardize domestic coral propagation to minimize the wild collection of coral. I hope to see more work like this in the future, especially for salt water fish.

Geosesarma hobbyists are also working to spread care and breeding best practices amongst themselves. One occasionally sees these crabs sold as "freshwater aquarium crabs" - although they will survive, they will not thrive in an all-water environment. Vivarium (all land) or paludarium (some land, some water) setups similar to those used for tropical frogs work best. There's quite an of overlap between the two hobbies, and decades of terrarium setup and care knowledge available from the frog crowd. Using information available instead of trying to reinvent the wheel means that there are fairly decent care sheets available. There is a small but enthusiastic Facebook group dedicated to Geosesarma care and breeding. There's also the occasional super-hobbyist (this one happens to be a biologist in his day job) who post their setups online. One can also find information on various tropical fishkeeping and tropical invert message boards - the fishkeeping and invert worlds are one of the few places where I've found message boards to still be a common form of communication in the 2015 Internet.
posted by RogueTech (5 comments total) 17 users marked this as a favorite
 
We used to tease my Dad by calling him "crab eyes" at the beach. We had noticed some similarity. Then we would run away. Suddenly one day my ex brought over two aquariums, a fourty gallon and a twenty. We got three fiddler crabs. They would hang out on the top of the big rock and wave their big arm, which terrified my little daughter in the night. Turning off the light at the top didn't help. Then one day they were gone. A week went by and the girls were yelling in the kitchen about a big bug eating the cat chow. The crabs had migrated the entire lenght of the house foraging. I now realize they needed more meat in their diets. Hindsight. Crab Eyes!
posted by Oyéah at 7:49 PM on September 24, 2015 [9 favorites]


That's what you get for teasing your Dad.
posted by leotrotsky at 4:02 AM on September 25, 2015 [4 favorites]


Firstly, those are just beautiful crabs. I highly recommend clicking on the caresheet link to see pictures of several differently-coloured species!

Thanks for the links, RogueTech, and thanks especially for the information on the captive-breeding work people are doing -- that's very reassuring, after the distressing state of affairs described in the Live Science article. Peter Ng should be commended for the effort he's put in tracking down the crabs' place of origin. It's very upsetting to think of all the amazing species that might be endangered beyond the point of no return before they are recognised and protected.
posted by daisyk at 5:27 AM on September 25, 2015 [2 favorites]


Those tiny little guys are cute, and the care sheet sounds like maybe they'd be fish friendly in a paludarium with a larger water area (maybe, if well fed . . . )

I only recently entered the fishkeeping world and was surprised how many new species have been discovered since I was a kid and my parents had tanks--mainstays like cories were simply unknown in the '70s. In that context hobbyists discovering and trying to breed crabs makes sense. Hobby relevant biology gets crowdsourced.

The flip side of the hobby is that environmental damage from overcollecting is way more common than I thought. Some stories remind me of the Victorian age, when amateur scientists expressed their love for life's creatures by killing and stuffing them.
posted by mark k at 6:49 PM on September 25, 2015 [2 favorites]


Yeah, it's one of the reasons why I kept freshwater when I had fish. I went for captive bred fish, and as gorgeous as salt water fish are, most species are still wild caught. I agree with your perception and you're right - we do sound like the Victorians, and that's not a good thing.
posted by RogueTech at 8:20 PM on September 25, 2015 [1 favorite]


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