Observation of the Week, 1/5/17

This Marbled Swamp Eel seen in Cuba by @henicorhina is our Observation of the Week!

“I have only recently started using iNaturalist,” says Oscar Johnson, a graduate student at Louisiana State University Museum of Natural Science who’s studying the population genetics of Amazonian birds. “ [And] I am slowly going through a massive backlog of photos that I have on old hard drives and adding them in to iNaturalist.”

One of those photos is the one above, showing the remarkable Marbled Swamp Eel. Oscar encountered the fish while on a trip to Cuba in 2008, where he had been visiting a friend. “Towards the end of the trip I went to a small town on the outskirts of the La Güira National Park, which I had heard was a good area to look for the endemic Blue-headed Quail-Dove. I arrived late at night and the innkeeper told me about a small trail heading into the woods that was good for herps at night, so I set off for a few hours of wandering,” he says. “I came upon this very shallow rocky stream and was surprised to find an eel swimming around in three inch deep water! I managed to get one good photo, which I later showed to one of the curators at the Natural History Museum in Havana, who was able to identify it for me.”

Not true eels, Marbled Swamp Eels are members of Synbranchidae family of ray-finned fish. Synbranchidae are well-adapted to living in shallow water and even making long sojourns on land; the lining of their mouths, full of blood vessels, allows them to breathe air quite well. They tend to be nocturnal and are known to eat insects, spiders and both tadpoles and adult frogs. When they hatch, Swamp Eels have pectoral fins for several weeks, after which time they shed them. And even more bizarre, Swamp Eels are sequential hermaphrodites, meaning that most are born female and become males later in life.

Oscar is continuing to upload his treasure trove of photos to iNaturalist, and says he’s “found it to be an incredible resource for any group of organisms. The community is incredibly knowledgeable and helpful with even the toughest identifications...It feels good to have these photos in a place where they will be put to good use!”

- by Tony Iwane


- Here’s Oscar’s personal website, featuring his photos and research.

- Asian Swamp Eels, a common food item in Asia, have been introduced to the United States and are now considered an invasive species there.

Posted by tiwane tiwane, January 06, 2017 04:36

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