Sea cucumbers, the organisms you probably always had underestimated.

8 reasons why sea cucumbers are probably aliens and will rule us all:

  1. They have no brain and no heart
  2. They breath via their anus.
  3. They provide a lovely shelter. Some fish decided to live inside their anus.
  4. They can poop out they guts as a defensive response and just regrow them
  5. They are the “vacuum cleaners” of the oceans
  6. They can change sex if they feel like it
  7. Some species can survive if cut into 2-3 pieces, each piece will grow into a new animal
  8. They can survive extreme conditions by just shutting down their biological activity until it’s more comfortable again

To sum it up: Sea cucumbers are either the end of evolution or just a superb creation of nature. They might not really look like it, but they sure are spectacular!

A beautiful sea cucumber

Fig. 1 A sea cucumber – With courtesy of Oliver Leyba

Why are sea cucumbers important for the ecosystem?

Sea cucumbers are deposit feeders, which means they eat sand and filter the organic material. They function like “vacuum cleaners“, and contribute to the recycling of nutrients, such as ammonium. This ecosystem service provided by sea cucumbers benefits other marine organisms, because they keep the sea floor “clean”. But they don’t just clean the seafloor, sea cucumbers also contribute to the process of overturning and reworking the sediment layers. That’s good for the sediment, because the exchange at the water-sediment interface leads to higher oxygen supply in deeper sediment layers, which supports the biodiversity of microorganisms.

If sea cucumbers are removed in great numbers, the sea floor can become sullied and uninhabitable.

Fig 2. Close-up on a sea cucumber - Nuri Steinmann

Fig 2. Close-up on a sea cucumber – Nuri Steinmann

How could farming and aquaculture help to save this species?

Besides their pure magnificence, sea cucumbers are also very popular for other reasons. Especially in East and Southeast Asia, namely China, sea cucumbers are considered as a luxury food, and believed to have special healing powers. They taste good and may treat cancer, wouldn’t those be reasons 9 and 10 why sea cucumbers are gifts from heaven? Well, while taste is subjective, and their healing powers have still to be proven, these alleged features have led to a worldwide decline of sea cucumber populations due to overfishing.

Driven by the ongoing exploitation of wild populations, the aquaculture and sea-ranching of valuable sea cucumbers species, have become an important and viable livelihood activity for coastal communities in developing countries. The farming of sea cucumbers is thought to not only provide an economic value for local communities, but to also reduce the fishing pressure on wild populations. The farming of sea cucumbers is mostly carried out in sea-ranching systems. Sea-ranching is defined as the introduction of juveniles (either hatchery-produced or wild-caught) into the natural environment until they reached the desired size.

Fig 3. Sea cucumber farming in Zanzibar – Nuri Steinmann

You can also help! I am fundraising my Masters project.

If you want to help or just want to learn more about sea cucumbers, have a look at my GoFundMe campaign (there are cool pictures too).

Author of this blog post.

Nuri Steinmann
Nuri SteinmannBSc. Bremen University
My research project