Survey 1 - Rubha Mor Site Survey – Monday 19 September 2016

This was the first survey by MSS of the shellfish farm in Loch Creran where Didemnum vexillum had been reported by the Scottish Association of Marine Science (SAMS – E Cook-Cottier, pers. comm.) on 1 September 2016. While SAMS had previously found approximately 10% of oyster bags to have D. vexillum fouling, this survey found approximately 0.1% fouling (i.e. 40 bags in a total of approximately 40,000). It should be noted that the initial SAMS survey was of the far western extreme of the farm, and was conducted before the farm started to manage the D.vexillum.

No samples were taken during this survey.

Survey 2 – Farm and Foreshore – Monday 26 September 16 to Wednesday 28 September 2016

Although this was planned to be a second survey of the farm, in order to see how D. vexillum had spread, this was abandoned as the farm site was obviously heavily managed (i.e. infected bags removed from the trestles and treated whenever Dvex observed), as was appropriate for an invasive non-native species. Hence time on site was used to conduct a detailed visual foreshore survey around the Loch, as well as to collect live samples of D. vexillum to take back to the containment aquarium in Aberdeen for trials and tests.

The live samples consisted of D. vexillum attached to oyster bags. Sections were cut out and the fouled sections, along with some fouled oysters, returned to the containment aquarium in Aberdeen. These live samples were subsequently confirmed as D. vexillum using molecular techniques.