Distance-Based Sampling Methods for Assessing the Ecological Effects of Offshore Wind Farms: Synthesis and Application to Fisheries Resource Studies

Elizabeth T Methratta

doi:10.3389/fmars.2021.674594

Abstract

Renewable energy, sustainable seafood, and a healthy marine ecosystem are integral elements of a sustainable blue economy. The rapid global advancement of offshore wind coupled with its potential to affect marine life compels an urgent need for robust methodologies to assess the impacts of this industry on fisheries resource species. Basic Before-After-Control-Impact (BACI) and Control-Impact (CI) designs are the most common experimental designs used to study the effects of offshore wind development on fisheries resources. These designs do not account for spatial heterogeneity which presents a challenge because empirical evidence shows that impact gradients occur at wind farms, with larger effect sizes close to turbine foundations that attenuate with increasing distance. Combining the before-after sampling design with distance-based methods could provide a powerful approach for characterizing both the spatial and temporal variance associated with wind development. Toward enhancing future monitoring designs for fisheries resource species at offshore wind farms, this paper aims to: (1) examine distance-based sampling methods that have been or could potentially be used to study impacts on fisheries resources at offshore wind farms including distance-stratified BACI, distance-stratified CI, Before-After-Gradient (BAG), and After-Gradient (AG) methods; (2) synthesize the methods and findings of studies conducted to date that have used distance-based methods to examine ecological impacts of offshore wind development for benthic macroinvertebrates, finfish, birds, and small mammals; (3) examine some of the central methodological elements and issues to consider in developing distance-based impact studies; and (4) offer recommendations for how to incorporate distance-based sampling methods into monitoring plans at offshore wind farms.

Highlights

Offshore wind is a rapidly advancing industry around the world
Effects on these taxa may occur through several impact producing factors (IPFs) that occur during each stage of development and that span multiple spatial and temporal scales (Figure 2; Degraer et al, 2019, 2020; Dannheim et al, 2020; Gill et al, 2020; Hutchison et al, 2020; Mooney et al, 2020)
Toward enhancing future monitoring designs for fisheries resource species at offshore wind farms, the goals of this paper are to: (1) examine distance-based sampling methods that have been or could potentially be used to study impacts on fisheries resources at OWFs including distance-stratified BACI, distance-stratified CI, Before-After-Gradient (BAG), and After-Gradient (AG) methods; (2) synthesize the methods and findings of studies conducted to date that have used distancebased methods to examine ecological impacts for benthic macroinvertebrates, demersal finfish, birds, and small mammals; (3) examine some of the methodological elements and issues central to developing distance-based impact studies; and (4) offer recommendations for incorporating distance-based sampling methods into monitoring plans at OWFs

Summary

Introduction

Offshore wind is a rapidly advancing industry around the world. Along the Atlantic coast of the United States, there are currently 17 commercial leases (Figure 1), and additional areas on the Pacific coasts of California and Hawaii are being explored for possible development. Assessing Offshore Wind Farm Impacts including mollusks and crustaceans), and their habitats have gained major attention because of their ecological and economic importance and because of the implications that these effects may have for fishing communities (Gill et al, 2020; Methratta et al, 2020; Perry and Heyman, 2020) Effects on these taxa may occur through several impact producing factors (IPFs) that occur during each stage of development and that span multiple spatial and temporal scales (Figure 2; Degraer et al, 2019, 2020; Dannheim et al, 2020; Gill et al, 2020; Hutchison et al, 2020; Mooney et al, 2020). BACI has proven to be a useful tool in demonstrating effects due to such anthropogenic interventions as sewage spills, aquaculture, and fisheries exclusion (Smith et al, 1999; Aguado-Giménez et al, 2012; Moland et al, 2013)

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Conclusion