2011 Scottish Natural Heritage (SNH) Scotland Didemnum vexillum records

The carpet sea squirt (Didemnum vexillum) is an invasive non-native species of colonial sea squirt that has recently been found in England, Ireland, Wales and at one location in the Clyde, on the west coast of Scotland. The potential ecological and economic impacts of this species are significant. A rapid response eradication programme in Holyhead Harbour is currently underway, showing signs of some success so far. However, it is not known how far this species has spread within the UK, and surveys are underway in England and Wales to determine its distribution. It is crucial to know as soon as possible how far it has spread, as
this information will determine what the appropriate response will be - if it is confined to only a few sites, it may be possible to attempt eradication. If it is already more widespread, then containment or control measures will be more appropriate.

No specific surveys targeting this species had previously been carried out in Scotland, so it was not known whether it was present just in the one marina in the Clyde or whether it was more widespread. This project involved a series of rapid assessment surveys of those marinas and harbours thought to be most likely at risk from establishment (e.g. those in the Clyde and on the west coast of Scotland) and will inform SNH’s policy for dealing with this species, as well as the wider UK policy for response.

毯海鞘（Didemnum vexillum）是一类群居海鞘的入侵性外来物种，近期在英格兰、爱尔兰、威尔士以及苏格兰西海岸克莱德湾的一处海域被发现。该物种具备显著的潜在生态与经济危害。霍利黑德港目前正在实施快速响应清除计划，截至目前已显现出一定成效。但目前尚不明确该物种在英国境内的扩散范围，英格兰与威尔士正开展相关调查以明确其分布情况。尽快明确其扩散范围至关重要，因为该信息将决定后续的应对策略——若该物种仅局限于少数分布点，则可尝试开展清除工作；若其已广泛扩散，则采取围控或管控措施更为合理。
此前苏格兰未开展过针对该物种的专项调查，因此无法确定其是否仅存在于克莱德湾的一处游艇码头，亦或是已出现更广泛的分布。本项目针对被认为最易遭受该物种定植入侵的游艇码头与港口（例如克莱德湾及苏格兰西海岸的相关设施）开展了一系列快速评估调查，其结果将为苏格兰自然遗产署（SNH）应对该物种的政策制定，以及英国整体的应对策略提供依据。