The ocean energy development is one of the main pillars of the EU Blue Growth strategy. However, while the technological development of devices is growing fast, their potential environmental effects are not wellknown.
The SafeWAVE project aims to improve the knowledge on the potential environmental impacts from Wave Energy projects. In the project scope, Work Package 2 aims to collect, process, analyse, and share environmental data related to four priority areas of research: i) Electromagnetic Fields, ii) Acoustics (noise), iii) Seafloor integrity, and iv) Fish communities. Four sites where Wave Energy Converters are operating in Portuguese, Spanish and French coastal waters will be monitored, representing different types of technology, different types of locations (onshore, nearshore, and offshore), and different types of project scales (single devices and arrays of devices), hence, different types and/or magnitudes of environmental impacts.
The aim of the present report (Deliverable 2.5) is to present the work done related to the conditioning and tunning activities of ITSASDRONE (an autonomous marine surface drone), test and check its operational procedure and navigation system and, finally, explore the association between Wave Energy Converters and fish aggregations around the Penguin WEC-2 of WELLO Oy which was deployed off the coast Armintza, Basque Country, Spain in August 2021. On 19th of December 2021 the WEC was towed to harbour for inspection, maintenance, and repairs due to the detection on the 28th of November an alarm of leakage. Although the plan was to repair Penguin WEC-2 and bring it back to its localization in BiMEP area, after more than 10 months, the penguin is still in the port of Bilbao. We, therefore, decided to carry out the monitoring work around the HarshLab floating laboratory device of Tecnalia.
Even if HarshLab could be considered as a good model of the possible reef or fish attraction effect due to its similar dimensions with the WECs, it does not have specific elements of the WECs that can intervene or affect this potential effect. Underwater noise generated by the moving parts of the harnessing machine inside the WEC, and the electromagnetic fields of the exporting electrical cables could generate an avoidance effect and compensate the attraction of the floating structures of the devices.
According to the results of the project, the ITSASDRONE proved to be a viable autonomous vehicle for fish school monitoring under the conditions of this study. It still needs some technological improvement related to navigation system, but in general, the ITSADRONE meets the objectives for which it was conceived and could be an excellent monitoring technique due to its capacity to work remotely and in near shore areas.
Schools of unidentified small pelagic fish were observed distributed throughout the water column, predominantly near the bottom in the device area. The acoustic sensors showed a relatively high abundance in the BiMEP area, in general as high or higher than in the access route from Armintza harbour. However, those results are preliminary result, and they should be considered as baseline information. Future studies are needed to further explore the association between WECs and fish aggregations.