Offshore wind - diadromous fish: review - January 2024

4. Concluding Remarks

Offshore wind energy is rapidly increasing and will reduce greenhouse gas emissions and help achieve current Net Zero targets. However, this developing technology must be considered in tandem with the need to protect and increase marine biodiversity

This report synthesised the available evidence on the potential interactions between offshore wind and 10 diadromous fish species. A review of the available literature of the potential impacts associated with the development of offshore wind power on the 10 diadromous fish species was carried out. It was clear from the literature review that there is a lack of scientifically robust information. Despite outlining many potential impacts in the report, there currently is not enough evidence to confirm or estimate the significance of these possible challenges to diadromous fish species. Expert panel workshops, comprising leading scientists and managers in the respective fields, affirmed these conclusions. Therefore, as part of this report, assessments of the potential impacts on the 10 focal species were provided, however given the state of the science at the time of writing, the opinions expressed by the authors have been formed with low confidence.

Due to the extensive evidence gaps identified in the report, it is difficult to inform best practice for the further development of offshore wind. Specifically, a lack of knowledge on the distribution and marine space use of the 10 focal fish species limits our understanding of, and approach to, potential mitigation measures. Accurately mapping the spatial-temporal distribution of the ten fish species within the proposed development areas is one of the first steps to understanding the potential impacts associated with offshore developments.

The report highlighted four key areas of potential impacts (sound and vibration, light pattern changes, novel habitat creation, electromagnetic fields) which may arise from offshore wind developments and future research needs associated with each of these areas. There was no consensus, at a strategic level, of a priority order associated with any specific potential impact source.

Given time constrains driven by the twin crisis of climate change and biodiversity loss, it is essential that the approach to filling the identified knowledge gaps should encompass both the sources of potential impact coupled with addressing information gaps regarding the spatio-temporal distribution of the 10 focal species. As such, there is an urgent need for targeted studies to address the knowledge gaps and priority should be given to projects which are time and cost effective, as well as, have the potential to address multiple questions concurrently. Many, if not all of these, require an interdisciplinary approach and a combination of field and laboratory based studies.