Gustav Paulay, curator of marine malacology at the Florida Museum of Natural History, explains sea cucumbers and describes some of the research on this unique animal. He also explains how researchers, through DNA sequencing techniques, have learned there are many more species of sea cucumbers than previously believed. He also details why they are an important resource.
Interview and videos produced by Sarah Stern for Explore Research at the University of Florida.
Gustav Paulay: Sea cucumbers are echinoderms and that is the group of animals to which sea stars, sea urchins, sea cucumbers of course, and a couple of other groups belong to. Sea cucumbers are unique because they are worm-like animals, even though they are echinoderms. They are really amazing worms in the sense that they dominate the planet. If you think about it the largest part of our planet is the deep sea floor and sea cucumbers are one of the most abundant forms of life on the deep sea floor.
They can do things that you couldn’t even imagine. For example they can eject their guts, throw them away, and make a new one. They can break their body into two pieces and each half regenerates the other half. They have a lung, but their lung is not through their mouth but through their anus. So they actually breathe through their butt. Even though sea cucumbers are really bizarre very ancient looking animals without a brain, with a very simple body, they are actually very important model systems for understanding what vertebrates are about and how we tick biologically, so to speak.
We have gotten very seriously into determining the different kinds of sea cucumbers and we thought we knew what the sea cucumber species of the world were, but ever since people started sequencing DNA, which is the genetic makeup of organisms, we have discovered that many of the species we thought we knew are actually more than one and some species turned out to be 2 some others 3. We basically have to redo much of the biodiversity and taxonomy that we thought we knew in the world and one of the interesting questions that we are currently working on is a group of sea cucumbers that are called the teatfish because they have these little little bumps on their bodies, and they were thought to be initially to be one species, and in the last study found them to be three, now we’re up to six different species based on DNA work and other morphological work, and so we’re discovering species of these that are unknown and yet they are totally over fished already. They are almost fished down to extinction before we even discover who they are.
People think that we know most things about life on Earth, but we really don’t and and being a biologist today to see this diverse in the ocean and really realize how much of this still unknown just blows my mind, and when we shared this information with some of these island nations where really the ocean is the livelihood of these places, the people there are really receptive to it and we have managed to close some sea cucumber fisheries on some of the Pacific Islands by basically explaining to people the life cycle of these animals and what overfishing does and how they can protect their reefs and the animals are so valuable that the ideal situation is for them to have a sustainable fisheries so that they can rely on these resources into the future.
Learn more about the Invertebrate Zoology collection at the Florida Museum