Electrofishing for razor clams: scientific trial update - 1 February 2022 to 31 January 2023

8. Other Work Streams

A PhD project (in collaboration with SAMS) is due to conclude its third year. The PhD student is registered through the University of the Highlands and Islands (UHI) and based at the Scottish Association for Marine Science (SAMS) near Oban. The PhD aims to assess the ecological sustainability of a well-controlled electrofishery for razor clams in Scottish coastal seas. In particular, the project is focussed on investigating the effects of exposure to electric fields on the physiological performance of both target and non-target marine species.

To examine the impacts of exposure to razor clam electrical fishing apparatus on marine animals, an electrical fishing rig was used for tank-based experiments using razor clams, starfish (Asteria rubens), and shore crabs (Carcinus maenas). After an approximate two-minute period of exposure to the electrical field, physiological metrics of stunned and control animals were tracked to assess the medium- to long-term impact of stunning. The results are currently being analysed and will be reported once available.

MD worked in collaboration with SAMS and trial participants to develop survey methodologies for razor clams. Surveys to determine razor clam densities were conducted in the Sound of Harris and Firth of Clyde in 2017 (prior to the trial commencing) (Fox, 2018). This work established the application of electrofishing with towed video as a new survey method for razor clams (Fox et al., 2019).

Planned surveys of razor clam grounds in the Firth of Forth and the Firth of Clyde, were scheduled for 2019 but deferred for operational reasons. Survey work in the Firth of Forth was carried out in March 2020 by SAMS (Fox, 2021). Although the work was curtailed and the report delayed because of the COVID-19 pandemic, it provided data on the densities of razor clams on fishing grounds and data on other organisms observed. Further surveys were planned for 2021 and 2022 but issues securing appropriate funding meant that these did not take place. Surveys of the Tarbert Bank are scheduled to taken place in 2023 with additional plans to survey the Clyde. The survey reports will be published online following completion and analysis.