Strategic Review of Offshore Wind Farm Monitoring Data Associated with FEPA Licence Conditions: Marine Mammals

Abstract

Two rounds of offshore wind farm development have been licensed in UK waters. Each wind farm has to meet certain monitoring requirements, as detailed in its specific FEPA licence. In this review, FEPA monitoring protocols and subsequent data associated with marine mammals collected to date at operational wind farms were assessed, with a key aim to inform future monitoring programmes for Offshore Wind Farm developments.

There are currently 5 operational offshore wind farms in UK waters. The FEPA marine mammal monitoring conditions for these Round 1 wind farms were minimal or absent. In some wind farms no monitoring was required and in others monitoring was only required during the construction phase and specifically for impact mitigation purposes. In one wind farm (Scroby Sands), a long term monitoring plan was required under FEPA licence conditions to cover pre-construction (baseline), construction and operational phases of development, specifically because it was recognised that this wind farm was being developed near a known sizeable seal haul out.

The lack of dedicated monitoring across operational sites makes it difficult to compare data collected so far. This is further complicated by generally poor reporting of monitoring protocols and data collected. FEPA licence conditions for Round 2 wind farms were strengthened and became more consistent and consequently many of the issues raised by this review have already been addressed in the more recent licences.

International case studies such as the Danish wind farms at Horns Rev and Nysted were examined to review the marine mammal monitoring data collected at those sites. Long term and wide-scale dedicated marine mammal surveys were carried out at these wind farms during all project phases (including baseline). The overall conclusions of these studies suggested that noise during construction (the major issue) led to clear avoidance reactions at considerable distances, with abundances appearing to return to close to normal post-construction. Notably, different reactions by marine mammals were recorded at these sites, so it is important to note that reactions may be both site and species specific.

This review highlights that FEPA licences are concerned mainly with the construction phase of a development and consequently monitoring is often limited to that phase. Recommendations on how recent licences might be further improved have been made in this report. Recent licences put the onus onto the regulators such as Natural England or Countryside Council for Wales to determine if longer term monitoring is required. This may lead to lack of consistency in data collection and reporting.

The need for more intensive baseline data collection is considered important in assessing the potential impacts of future developments. The impacts caused by direct injury due to anthropogenic noise can likely be significantly reduced with appropriate mitigation without the need for a detailed baseline. However, appropriate mitigation to reduce potential indirect impacts (e.g., due to disturbance) will vary by species, time period and by location. Clearly, Round 3 wind farm development areas, being further offshore, are potentially areas where information on marine mammal abundance is sparse or lacking. Consequently, it is considered that baseline data is required not only to appropriately adapt mitigation measures, but also to assess the success of mitigation practices and the overall impact of each project phase. It is important to standardise survey methodology and reporting. It may also be required to carry out more intensive surveys using telemetry or photo identification for example to investigate whether certain habitats are important foraging areas for marine mammals. It is also useful to incorporate noise measurements made during development into marine mammal data analysis and future mitigation.

Recommendations for future Round 3 wind farm development are made. It is considered the primary concerns are the far larger scale of these developments and their locations even further offshore. Offshore construction has the potential to impact on a wider variety of marine species, many of which have been poorly studied. For example, offshore developments may impact on the migratory routes of baleen whales. Large scale development may cause large scale displacement of species from important habitats, especially given that construction activities will likely take place over an extended period of time compared with smaller Round 1&2 wind farms. Larger scale projects increase general concern over ship interactions, pollution and EMF, in addition to ever present anthropogenic noise issues.

Related Reports:

This document is related to the Scroby Sands Wind Farm Project Site.