TY - RPRT
TI - Impact of geophysical and geotechnical site investigation surveys on fish and shellfish
AU - Duffy, O
AU - Chumbinho, R
AU - Coca, I
AU - Breslin, J
AB - BlueWise Marine (BWM) has been engaged by Wind Energy Ireland (WEI) to deliver a desktop study on the impact of Site Investigation Surveys on Fish and Shellfish.As part of the preparation process for offshore renewable energy (ORE) developments (in fact, for any engineering activity in the marine environment), the collection of environmental data is essential to inform downstream activities such as design of structures and infrastructures, planning of operations, consenting, assessment of environmental impact, etc. This process starts with a review of existing environmental data for the target site, usually followed by a dedicated survey to collect specific or more detailed data. These preliminary surveys are known as Site Investigation Surveys (other surveys may be required later in the development to acquire even more detailed information).Ireland’s Offshore Wind Energy programme includes a target to deploy at least 5GW of offshore wind energy by 2030, as part of the Government’s objective to generate 80% of Ireland‘s electricity from renewable sources by 2030. These decarbonisation goals have resulted in a significant interest from wind farm developers to develop projects in Irish waters. Initially led by the developers themselves, this interest has resulted in a high number of applications for Site Investigation Surveys throughout Ireland’s Territorial Sea and EEZ filed with the Foreshore Licensing Unit (FLU) (see Figure 1.1). This, in turn, led to an increasing concern among the fishing communities regarding whether and how these surveys (sometimes overlapping in the same area or at the same time) might reduce catches of fish and shellfish in addition to displacing fishers from their grounds. Concerns arose over possible physical, behavioural and physiological impacts.The transition to a plan-led approach to ORE developments has made it clear that many of the Phase 2 developer led surveys will not take place. Nonetheless, the need to better understand the possible impacts of Site Investigation Surveys on the locally important fish and shellfish species remains. This desktop study aims to identify the nature and extent of the impacts which have been observed following scientific surveys and experiments to assess the impacts of geophysical and geotechnical equipment and surveys on fish and shellfish.Given the diversity of marine life (even when only the commercially important fish and shellfish are considered) and of environmental factors affecting it, the assessment of the likely impact of Site Investigation Surveys is no simple task. As it will be seen in later sections of this study, surveys largely use sound and mechanical devices to collect data, sediment samples and cores. The scientific community has been studying ocean acoustics for more than a century, and the impact of sound on marine life for several decades already. However, early studies were focused on impacts on large marine mammals, and then later on all marine mammals (in fact, the effects of sound on marine mammals became a major and mediatic source of concern and the object of conservation measures 40 or 50 years ago).Only more recently (from the late 1970s) have studies about similar effects on fish and shellfish become available. The research on this topic was driven originally by public awareness of the levels of sound produced during high resolution seismic surveys carried out by the Oil and Gas industry and possible impacts on marine mammals (first) and on fish (later), and also by the need to understand the response of commercial fish species to sound produced by equipment such as fish finding sonars and trawl net locators. Unsurprisingly, a large number of studies and reviews focus on high intensity, low frequency sound sources, such as those produced by the airgun arrays used during high resolution seismic studies.Studies on the impacts of underwater acoustics have gradually expanded to understand the effect of anthropogenic acoustic noise in general, spanning all frequency ranges and sound source levels. In recent years, these studies have increased significantly (apparently motivated by scientific curiosity) and a relatively large number of studies on diverse aspects of impact of sound on marine species is now available online. Despite this fact, there are significant knowledge gaps. For instance, while there are several studies on important commercial finfish species such as cod, herring, or mackerel (or similar), studies on shellfish are less common and in the case of gastropod molluscs such as whelk are non-existent. Furthermore, research tends to focus on controlled experiments using, for example, fish and shellfish within confined tanks. These results need to be carefully assessed as they often misrepresent the physical scale, fish behaviours and conditions found in the open sea environment.To address the above challenges and in an attempt to arrive at meaningful and useful results, BWM developed a workplan that included the following steps:Review of data made available by the International Council for the Exploration of the Seas (ICES), the Sea Fisheries Protection Agency (SFPA), the Central Statistics Office (CSO) and by fishers or fisheries associations to determine commercially relevant species.Engagement with fishers to define the scope of work and agree on a list of the most commercially important species the study should focus on.Identification and description of survey techniques and equipment more commonly used in site investigation surveys for offshore renewable energy developments, to quantify the relevant acoustic properties such as source levels and frequencies, since underwater sound is the most important manmade disturbance to the marine environment during surveys.Systematic review of scientific literature on known impacts from underwater acoustic and mechanical pressures on the marine species of interest for the study, arising from surveying activities, as well as consultation with relevant organisations (Bord Iascaigh Mhara, Marine Institute). In the case literature was not found for a specific species, the review used literature on similar species (physiologically, or those belonging to the same taxonomic family or genus).Cross-checking of learnings from the literature review with the species of interest in this study, to identify and tentatively quantify possible effects of surveys on those species.Discussion of the results of the review and learnings and drawing of conclusions.Preparing and writing this Desktop Study report.This report, detailing the results of the above workplan, is structured as follows:Section 2 contains a description of the typical research activities carried out during Site Investigation Surveys (sub-sections 2.2 to 2.5), an analysis of current Site Investigation License applications in terms of surveys foreseen and type of equipment expected to be used (sub-section 2.6), and a compilation of the technical characteristics of the acoustic devices (or sound producing equipment) used in Site Investigation Surveys and in other marine activities such as fishing (e.g., fish finding sonars), in sub-section 2.7;Section 3 presents the results of the fisheries data analysis, listing the most commercially important fish species in each region of Irish waters with the help of illustrative maps. Based on these listings, which have been validated with the assistance of representatives of fishers and their associations, a list of the most commercially significant species has been produced, further grouped into seven groups of species.Section 4 contains details of the systematic scientific and technical literature review of known impacts of sound on fish and shellfish, focusing on the species or groups identified and validated in section 3.Section 5 discusses the possible extension of known impacts into the context of Site Investigation Surveys, based on the findings from previous sections, as well as a discussion of unknown impacts and their likelihood; andSection 6 contains concluding remarks.
DA - 2023/11//
PY - 2023
SP - 122
PB - BlueWise Marine
SN - BD00722001
LA - English
KW - Wind Energy
KW - Fixed Offshore Wind
KW - Floating Offshore Wind
KW - Noise
KW - Fish
KW - Invertebrates
KW - Human Dimensions
KW - Fisheries
ER -