The orange-tipped sea squirt is an invasive species that has spread itself around the world.
It is highly successful and can establish a new population from only a few individuals, possibly even one.
It attaches to almost anything that is covered in seawater, including ship hulls and piers, and even grows on other organisms. It can adapt its shape to fit any available space.
Corella eumyota poses a threat to biodiversity and aquaculture.
Floating pontoons are often Corella eumyota's preferred settlement substrate. © R Huys
Corella eumyota is an invasive solitary sea squirt.
It belongs to the Tunicata, a marine group of underwater saclike filter feeders with inhalant and exhalant siphons.
Find out more about this sea squirt’s shape, and how it moulds itself to fill the available space.
Discover where you're likely to find Corella eumyota.
Although the orange-tipped sea squirt has limited means of dispersal, it has found its way to virtually every continent on Earth. But how?
Sea squirts are an invasive species that are easily spread around the world and pose a serious threat to biodiversity and commercial aquaculture. Find out more.
Get more information on Corella eumyota.
Corella eumyota forming dense aggregations in a marina in Weymouth, Dorset.© JDD Bishop
Floating pontoons - made of ropes, tyres, buoys etc. - are often the preferred settlement sites for new arrivals, and have become the primary focus for rapid assessment surveys for alien species.© R Huys
Ropes are an ideal substrate for Corella eumyota and other sea squirts to colonise.© R Huys
Seven individuals of the orange-tipped sea squirt on a dead Pacific oyster (Crassostrea gigas – another non-native species) in Noss Mayo, Devon. Note the typical orange coloration of the siphons and the black U-shaped hind-gut.© JDD Bishop
The extreme clumping behaviour (settlement on conspecifics and moulding into the shape of the existing surface) could turn Corella eumyota into a nuisance, blocking pipes or obstructing installations.
[scale in cm]
Corella eumyota has the capacity to establish dense populations very rapidly. Here it dominates the submerged surface of a concrete pontoon, forming an almost continuous carpet in Vila Praia de Âncora, Portugal. The marina was built only two years before the survey.© A El Nagar
Space availability is the prime factor in the establishment of a non-native species. When space is limited Corella eumyota is capable of using any substrate, including other sea squirts such as Ascidiella aspersa. Note the two young individuals in the middle.
Corella eumyota even uses other non-native species as substrate such as the leathery sea squirt Styela clava. It is assumed to have been transported on the hulls of warships following the end of the Korean War in 1951, and first introduced at Plymouth.© R Huys