This 1997 report indicated that trembling sea-mat Victorella pavida, a ctenostome bryozoan, was present in Swanpool, a brackish lagoon, and that it was abundant in various habitats. It wasthe only known UK site. The trembling sea-mat has a preference for the submerged stems of the common reed Phragmites australis and also for concrete and stone surfaces. In other habitats it was found to be occasional, rare or absent, probably due to reduced salinity or to the presence of varying amounts of silt. This rare animal species may be threatened by changes in salinity, silting and the effects of various pollutants in the medium term.
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