A recently-discovered invasive marine species most likely arrived in Langebaan from the Caribbean on the hulls of visiting yachts, according to a top biodiversity expert.
Amathia Verticillata is a highly invasive aquatic invertebrate that resembles patches of sea noodles. It was discovered in 2023 by a Stellenbosch student in Kraalbaai, and later confirmed to be well established in the Langebaan Lagoon. Experts say it has the potential to negatively impact on the Lagoon’s valuable biodiversity and potentially also affect infrastructure such as aquaculture farms.
SANParks marine biologist Dr Alison Kock believes the species arrived on the underside of yachts, raising concerns that it may spread further along the South African coastline – if it has not already done so.
“Unfortunately, it is already established in certain areas, eliminating the ability for us to go in and remove it completely,” Kock said in a recent CapeTalk radio interview. It was believed to have arrived either on the underside of boats or in ballast water. “It speaks a lot to awareness around yachts and ships that are coming from these other countries and the importance of cleaning those boats,” Kock said, adding that marine invasives were far less known than terrestrial ones because they were largely unseen. “Prevention is key. Once established it is nearly impossible to remove. We really need to look at a national level at what we are doing to prevent these alien invasive species getting into these systems in the first place. We can raise attention in the boating world. If you’ve got your yacht in Langebaan and you want to take it to Knysna, make sure you clean the underside of your hull.”
Commonly known as “spaghetti bryozoan”, the aquatic invader is hermaphroditic (has male and female organs) and can adapt to a range of temperatures and salinities. A recent survey suggests it thrives in warmer, calmer waters compared with colder and rougher conditions.