The Solent, much of which is designated as a Special Area of Conservation (SAC) and Special Protection Area (SPA), is noted as a key entry point for Invasive Alien Species (IAS) into the UK, due to its high volumes of international shipping and recreational boating: both major vectors of IAS. These IAS pose a threat to the Solent’s native biodiversity and recreation and fishery industries, especially shellfisheries, due to their potential to threaten native species, habitats or whole ecosystems.
Although there has been monitoring of IAS within harbours and marinas, the adjoining areas of intertidal habitat, have been largely ignored. However, there is a strong suspicion that IAS are much more prevalent on natural shores than has been documented. This project aimed to respond to this identified data and information gap by developing a replicable survey methodology to map IAS within marine protected areas in the Solent.
Rapid assessment surveys of 14 ‘Clusters’ of three sites, one marina/harbour site, one nearby shore and one more distant shore, were completed in the Solent, recording alien species (AS) and native species (NS) from target lists. This new data has also been compared with previous surveys of IAS in Solent marinas to provide a timeframe for assessment of the risk of colonisation of natural shores by IAS from nearby marinas.
This exploration of the association between IAS in marinas/harbours and intertidal areas will help inform policy and provide a baseline of IAS within the Solent Maritime SAC.
This report was first published on 14 April 2022, this version was updated to include Appendix XIII and republished on 28 April 2022.