‘Xenia elongata’, recently reclassified asUnomia stolonifera,是一个众所周知的软珊瑚水族馆吗hobby for its supernatural growth rates in reef tanks. This fleshy octocoral is so prolific that it has been used in dedicated chambers as a form of nutrient export because it grows so fast, sometimes even faster than some types of micro and macro algaes.
Over eight years ago this species ofUnomia(Xenia) was discoveredgrowing on reefs of the southern Caribbeanoff the coast of Venezuela and to no one’s surprise, this weedy soft coral has spread at an alarming rate. Any aquarists with a passing familiarity with ‘Xenia elongata’ will know how fast this coral grows and its exponential growth rate is not limited to aquarium conditions.
A new papertaking a look atUnomiaaround Venezuelahas found this coral growing pretty much everywhere, dominating every kind of habitat possible. From hard bottom to coral reefs and even seagrass habitats exhibited somewhere around 30 to 80% coverage by the invasiveUnomiaand it has been documented spreading by clinging to bits of detached floating seagrass which has helped the intruder spread across an alarming range in less than ten years.
“The high percentage cover of Unomia stolonifera in all the invaded sites significantly reduced the occurrence of stony corals, hydrocorals and other indigenous anthozoans.” Artisanal fishing practices with trawl nets is not only helping to spread the invasive coral species but the study also noticed thatUnomiawas most abundant where fish density was depressed as it is believed that some species of butterflyfish probably do some light grazing of the coral alien.
While the invasive xenia is so far only known across a range of 10 kilometers or so, it’s probably only a matter of timeUnomia stoloniferais spotted growing outside Venezuelan territorial waters. With no natural predators to control its growth and reduced biodiversity to prevent this coral from taking hold in the first place we fear it’s only a matter of time until the weedy xenia becomes permanently established in the Caribbean likeseveral invasive coral speciesthat have come before it.
