What is Sargassum?
Sargassum is a type of macro algae, which is either brown or dark green in colour. If you’ve ever been scuba diving in the Cayman Islands (or visited a beach anywhere in the Caribbean) you’ve probably encountered this free floating species of algae.
You can find sargassum in tropical and temperate oceans. The Florida Keys is well known for its high levels of sargassum. You may have noticed that sargassum has “berry like” structures, these are gas filled bladders which keep them afloat to promote photosynthesis. Floating mats of sargassum are an essential fish habitat; they provide shelter and become a nursery for large fish, including baby turtles and mahi-mahi, they’re also a food source for numerous marine species. Some species of frogfish go through their entire lifecycle without leaving the protection of the floating mats.
Sargassum in the Cayman Islands
There was a sargassum crisis in the summer of 2015; not only on Grand Cayman, but the whole of the Caribbean Sea. The gulfweed (the term used for any seaweed species washed on shore) accumulated on shore lines, creating piles up to 5ft high in some areas. The Cayman Islands were not as unfortunate as other Caribbean Islands, such as St Martin, in the sargassum crisis.
The sargassum influx is a result of climate change. Free floating macro algae is at the mercy of the current and wind, which has been changing over recent years. The nutrients from agricultural fertilisers and run of from cities can cause algae blooms too.
Sargassum and Tourism
The seaweed that gets washed onto the shore can have some negative impacts. Not only does it look unappealing to tourists (sorry guys, the beaches don’t always look like they do on the postcards…but it is a natural occurrence), it collects marine debris which consequently washes ashore too, and it can hinder turtle nesting.
Hotels across the island do their best to keep their beaches clean; the only way to do this is to manually removed the seaweed every morning. Some hotels use heavy machinery to aid them, though this can be detrimental to wildlife. The machines discourage turtles from coming to the beach and can crush turtle nests.