You can’t be a fan of the sea without being a fan of sea fans. In fact, we love these magnificent marine creatures so much we even named ourselves after them. We wanted to share the underwater love with you all. That’s why we’ve put together 12 reasons why we think sea fans are awesome.
Photo by Juanma Clemente-Alloza
1. Sea fans make the ocean
Sea fans are one of the most wide-spread creatures to be found throughout the world’s seas. There are hundreds of species of sea fans that mostly live on shallow water coral reefs. They’re especially abundant in the tropics and particularly in the Caribbean. Wherever there are strong currents, you may find forests of sea fans covering large areas of the seabed and occupying prominent positions along sea walls.
2. They’re all about team spirit
Sea fans are not a single animal. In fact, each fan is a colony of tiny coral polyps. These polyps are only millimetres in size and join together to form the delicate branching structures we all know and love. The polyps work together sharing nutrients to each other via their connecting tissue.
Photo by Nariman Mesharrafa
3. Sea fans are shaped by water
Fixed permanently to the seabed, a sea fan’s shape is based on the area they live. Fans will grow large and fan-like in shallow waters where currents are present as this shape allows the fan to flex with the current. However, in deeper, calmer waters sea fans grow taller, thinner and more rigid. Sea fans can reach over 1 meter high and wide, but it takes a while as they grow less than 1cm a year,
These soft corals do not have hard skeletons like the stony corals that build reefs, but instead have wood-like cores for support and fleshy rinds for protection.
4. They’re giant living nets
Each coral polyp that makes up a sea fan has eight stinging tentacles. Once night falls, each polyp spreads out these tentacles to catch plankton. This, coupled with the fans’ wide, branched shape, means this underwater marvel effectively becomes a giant net, ensnaring its prey as they sweep through on the current.
5. Sea fans dress to impress
The underwater world is full of colour and sea fans are no exception. They come in a range of colours sporting spectacular hues of purple, pink, red, yellow, orange or even white. They get their amazing colours from the algae that lives in the flesh of each coral poylp. There can be more than a million algae per square centimetre of coral polyp tissue. As well as giving the fan their fantastic colours, these photosynthesising creatures use sunlight and waste products from the polyp to produce oxygen and excess nutrients which the polyps can use.
Photo by Francisco Jesus Navarro Hernandez
6. They enjoy a full moon party
Once they reach maturity, sea fans spawn millions of sperm and eggs into the water column. This happens at certain times of the year, and usually around the full moon. Once fertilized the eggs turn into larvae and swim around for a while. If not eaten, they eventually descend onto what will hopefully prove to be a good new home. It then changes into a polyp ready to start its own colony. To do this it creates a clone of itself. These two produce another two. These four make eight, and so on… New colonies can also form if a fragment of an existing fan breaks off and manages to find a good place to secure itself.
7. They’re very hospitable
Look closely and you may spot a community of other creatures living within the branches of a sea fan. Fish, molluscs, sponges, brittle stars, basket stars, algae and more will set up home in the fan and monopolise on its sturdy position in a fast current to catch their own food.
Photo by Sea Fans – spot the trumpetfish.
8. Pygmy seahorses
If you are very lucky you may even spot a tiny pygmy seahorse perched on a branch tightly holding on by its tail. The seahorse’s body is coloured in the same shade as their host fan and covered in knobby appendages that look exactly like the polyps. The perfect camouflage.
Photo by Dorothea Oldani
9. They have chemical defences
There are few animals that will feed on a sea fan as it’s packed full of a foul-tasting chemical. But some animals have evolved to get around this like butterflyfish and sea snails. The flamingo tongue, a particularly attractive snail, is at least civil in its dining. It will eat just a small area of a fan before moving onto the next one to allow the original colony to recover. The flamingo tongue ingests the toxic chemical and repurposes it into its own flesh to deter being eaten itself.
Photo by Sea Fans
10. Dolphins use them for medicinal purposes
Dolphins will rub themselves against the branches of a sea fan in order to take advantage of the antibacterial qualities of the chemicals that the fans produce. Marine scientists are researching these compounds as they may have medicinal use for humans.
11. They’re not fans of being made into souveniers
Sea fans are beautiful. As a result of their attractive shape and colour, they’re collected, dried and sold as souvenirs and decorations – even turned into jewellery. Remember sea fans are animals, so it’s a bit like wearing fur.
They’re also harvested to be used in aquariums where their old name of gorgonians is still used. Dredging of the seabed for seafood such as scallops is also taking its toll on sea fans around the coastlines of many countries. Due to the overexploitation by these markets many sea fan species are now threatened, with some labelled as ‘vulnerable’ by the ICUN (International Union for Conservation of Nature).
Thankfully there are organisations focussed on preserving sea fans and promoting their conservation. Many countries now prohibit their harvesting and certainly if you are caught transporting any across borders you can get into a lot of trouble with heavy fines or even imprisonment. The Pink Sea Fan which lives around UK waters is an example of a vulnerable sea fan which is now protected under a governmental act.
12. They love being admired
The best way to experience sea fans is in the wild – grab a snorkel and a mask and dive-in. Remember, sea fans are fragile and easily damaged or dislodged. Always keep a safe distance – if you are going to go in closer to look for hidden critters, ensure your buoyancy is good and be aware of your fins. And never, ever touch a sea fan. Some divers will pull on a fan to arrange a photograph. If you see this happening, be sure to stand up for your sea fan friends and tell your tour guide.
Are you a fan of sea fans?
Hopefully you’re now well and truly a member of the (sea) fan club. Do you have a sea fantastic fact that we can add to our list? Share the underwater love in the comments below.
Looking for more facts about the underwater world, check out the different ways we’ve found that you can learn about the ocean.