One of the more interesting parts of being a Sea Grant agent is when people send me their “Do you know what this is?” mystery finds. Sometimes I immediately know the answer. Other times have to do some digging to figure it out. But the challenge is fun and in the end we all learn something new.
Now, while it’s no surprise that strange creatures lurk among us, the strangest ID I’ve made yet came from a local commercial blue crabber. He found this creature in 2014 in one of his traps up on the Peace River, and it was downright freaky. It looked a little like a Maine lobster, but with long skinny claws.
Freshwater critters are definitely not my forte, but my gut said some kind of prawn (large shrimp). Fortunately, I know a lot of scientists, and one of them sent me a couple of papers to help me key the critter out.
It turned out to be a big-claw river shrimp (Macrobrachium carcinus). The big-claw river shrimp is the largest of six native freshwater shrimp in Florida and one of the largest found in the United States. The species occurs from Florida to Brazil. I tried to find out where in Florida they are known to live, but the only distribution papers I found were from the 1940s and ‘50s. Those papers said they occurred in St. Augustine, Silver Springs, Miami and Big Pine Key. Papers that I found from the 1960s and ‘70s mostly focused on the aquaculture potential of freshwater prawns, including this species.
The big-claw river shrimp found in the Peace River was definitely a male, based on size. And it was the only record of one in the Peace River. After I made the identification, the Museum of Natural History at the University of Florida said they did not have a specimen in their reference library, and asked if they could have it. So our Peace River big-claw river shrimp was preserved, packed and sent to Gainesville.
Betty Staugler is the UF/IFAS Extension Charlotte County agent for the Florida Sea Grant Program. Contact her at firstname.lastname@example.org or 941-764-4346.