Learning more about “nature’s Roomba.”
By Kelly Currington

Sea cucumbers are an important part of the eco-system, yet many people know little about them, and some divers have never seen one of these amazing and beautiful creatures. Let’s take a look at these squishy, odd-looking “vacuums of the sea.”

There are around 1,000 different species of sea cucumbers world-wide, usually found on the sea floor near coral reefs, seagrass beds, and other fixed habitats at depths between 10 and 120 feet. The main three found in the Turks & Caicos are the Donkey Dung, the Furry, and the Tiger Tail, which can reach lengths of up to six feet. They do not swim, but caterpillar across the sea floor. They have an elongated body covered in a leathery skin with varying textures, patterns, and nodules. While they do not have a “true” brain or any distinct sensory organs, they instead have a complex network of neurons that help them experience touch and the presence of light.

This is the Tiger Tail sea cucumber, which can reach lengths of up to six feet.

How do sea cucumbers help the eco-system? That’s a great question, since based solely on appearance, they don’t look like they have a whole lot to offer, but they definitely do. They are suspension feeders, roaming the sea floor using small, tube-like feet to feed on algae, tiny animals, and decomposing matter; they also ingest sand, mud, and other sediment. They pull the nutrients from everything they ingest and then poop out clean sand and filtered water. Voila—an underwater Roomba!

Under normal circumstances, they are either stationary or moving in a cumbersome way, like a big clumsy caterpillar. However, if they feel threatened, they can kick into high gear by flexing their bodies and rolling away in an act of fear and self-preservation. If you happen upon one of these sea dwellers while swimming, snorkeling, or diving, please do not touch them, encroach on their space, make loud noises, or follow them if they start to roll away, as this causes great stress. If they continue to feel threatened, they can expel part of their toxic guts in an attempt to defend themselves from a predator, and  some species even shoot sticky threads from their bodies, entangling and confusing a predator to give them time to escape. But continued or repeated stress at this level can eventually be fatal, so please be respectful and quietly admire sea cucumbers from a healthy distance.

Another part of the sea urchin’s self-defense is the ability to blend in with their environment and be nearly or completely unnoticeable. This is crucial when trying to hide from natural predators like crabs, turtles, fish, and some species of shark. Sadly, their biggest threat is humans who farm and fish them for consumption, depleting their numbers significantly, pushing the species towards the threatened list. They are also at risk from climate change, ocean acidification, habitat destruction, and water pollution. If they can manage to stay off the menu and not succumb to other factors, sea cucumbers can live between five and ten years.

My first encounter with a sea cucumber was a funny one. My son and I were walking along Grace Bay Beach and wading in the water when we saw this large brown thing in the water. I thought it was excrement and all I could think about was how huge the creature must have been to excrete it. When I discovered that it was actually an animal, I laughed until my cheeks and sides hurt! 

This is the Furry sea cucumber. They do not swim, but caterpillar across the sea floor.

Even this did not give me all the education I needed before my first up-close encounter with a Furry sea cucumber while diving. There she was, so beautiful and intriguing, just lying there on the white sandy bottom. She suddenly lifted one end of her body up off the floor and opened and closed her mouth repeatedly. I couldn’t believe what I was seeing. I used my camera to record this incredible encounter. She continued this for 10–15 minutes and I was paralyzed with excitement. This secured my fascination with sea urchins, and I couldn’t wait to tell my mates what I seen and filmed. When I pushed play, the laughter was immediate and robust, so much so that they had a hard time getting the words out to tell me what they were laughing at.

After they caught their breath, they told me that I had spent half my dive filming her bottom, her bum—not her mouth! I laughed with them, but held firm on my happiness at witnessing an amazing sight.

Over the years I have come to love these little squishy pickles and all the good they do for the oceans. I can spend a whole dive watching one inch across the sea floor, studying its behavior, skin texture, and the deliberateness with which it moves. 

Sea cucumbers typically reach sexual maturity around three years of age. Their eggs are externally fertilized after the female releases her eggs into the water column and they come into contact with sperm released from a male. The best chance for this to be successful is for there to be numerous males and females together in the same area at the same time. 

There is a whole wonderful world below the ocean’s surface, so slow down and take the time to really see all the amazing and interesting creatures that are right in front of your eyes. They all play a vital role in keeping the reefs healthy and they all have interesting behaviors and characteristics. Everyone wants to see the big-ticket creatures like sharks, turtles, rays, and octopus, but there are so many fascinating unfamiliar creatures on the reefs that deserve the same respect and notoriety. The more you know about these creatures, the more you will want to protect them.

From the ocean to you . . . treasures galore!