ICES Journal of Marine Science

Pardo, Juan Carlos Farias; Aune, Magnus; Harman, Christopher; Walday, Mats; Skjellum, Solrun Figenschau

doi: 10.1093/icesjms/fsad191pmid: N/A

Offshore wind is one of the major fast-growing renewable energy industries, and sustainable implementation of offshore wind farms (OWF) is desired. Nature positive approaches have been proposed to promote biodiversity gain and improve ecosystem resilience. At the same time, coexistence has been considered a way to mitigate the race for ocean space and better integrate the development of the OWF industry. Here, we provide a systematic narrative synthesis review on nature positive approaches and coexistence in OWFs. We observed an increased interest in the topics over the last 5 years, with most of the documents coming from the northern hemisphere, in particular Europe and the North Sea. Literature is mostly related to bottom-fixed turbines, with relatively fewer documents available regarding floating offshore wind, which is a nascent industry. There is a lack of long-term in situ assessments of the impact of nature positive approaches. Whilst there are various biodiversity impacts of OWFs, the literature highlights the artificial reef effect and biodiversity protection and gain (diversity and abundance) for ecological and economically relevant groups. Coexistence strategies with OWF, such as fisheries, aquaculture, and marine-protected areas, bring positive and negative outcomes for the environment, and further investigation on their integration should be explored.

Davis, G E; Tennant, S C; Van Parijs, S M

doi: 10.1093/icesjms/fsad174pmid: N/A

Offshore wind energy is rapidly developing in US waters, with construction underway off Southern New England (SNE), an important region for many species, including the critically endangered North Atlantic right whale (NARW). A data-driven understanding of NARW upcalling behaviour is presented here to help establish proper monitoring protocols for mitigating impacts. Analyses of individual upcalls from 2 years of acoustic recordings showed that NARWs were detected at least 1 day every week throughout both years, with highest NARW presence from October to April. Weeks with more days of acoustic presence typically had more hours with calling activity, but the number of upcalls within a day or hour was variable, reflective of the social function of the upcall. Within SNE, on average, 95% of the time NARWs persisted for 10 days, and reoccurred again within 11 days. An evaluation of the time period over which it is most effective to monitor prior to commencing pile driving activities showed that with 1 h of pre-construction monitoring there was only 4% likelihood of hearing a NARW, compared to 74% at 18 h. Therefore, monitoring for at least 24 h prior to activity will increase the likelihood of detecting an up-calling NARW.

Cresci, Alessandro; Durif, Caroline M F; Larsen, Torkel; Bjelland, Reidun; Skiftesvik, Anne Berit; Browman, Howard I

doi: 10.1093/icesjms/fsad205pmid: N/A

Static magnetic fields (B-fields) are introduced in marine ecosystems by anthropogenic sources such as subsea power cables. Larvae of the gadoids Atlantic haddock (Melanogrammus aeglefinus) and Atlantic cod (Gadus morhua) disperse over the continental shelf and may encounter B-fields, which could alter their behavior. We tested the behavior of 184 gadoid larvae while they were being exposed to a B-field (22–156 μT), which is in the intensity range of that produced by a high-voltage direct current cable, for a duration of 10 min in a raceway tank. We present a reanalysis of published data on 92 haddock larvae combined with newly collected data on 92 cod larvae tested under the same settings. Exposure did not affect the spatial distribution of the larvae. Both species displayed the same proportion of nonexploratory (78%) and exploratory (22%) individuals. Exposure significantly reduced the average swimming speed of the nonexploratory larvae by 32% and the average acceleration by 30%. Exploratory larvae were not affected. These results indicate that the swimming behavior of a high proportion of gadoid larvae would be reduced by weak static B-fields. Consequences of exposure on dispersal and survival at the population scale awaits further work using biophysical-coupled models.

Searle, K R; O'Brien, S H; Jones, E L; Cook, A S C P; Trinder, M N; McGregor, R M; Donovan, C; McCluskie, A; Daunt, F; Butler, A

doi: 10.1093/icesjms/fsad025pmid: N/A

Governments worldwide are setting ambitious targets for offshore renewable energy development (ORD). However, deployment is constrained by a lack of understanding of the environmental consequences of ORD, with impacts on protected birds forming a key environmental consenting challenge. Assessing the impacts of ORD on marine birds is challenging, utilizing interlinked approaches to understand complex behavioural, energetic, and demographic processes. Consequently, there is considerable uncertainty associated with ORD assessments for marine birds, with current methods failing to quantify uncertainty in a scientifically robust, evidence-based manner. This leads to a high degree of precaution and a lack of confidence in the evidence used to inform ORD consenting decisions. We review the methods used to estimate ornithological ORD impacts in the UK, a country at the forefront of ORD. We identify areas in which uncertainty quantification could be improved through statistical modelling, data collection, or adaptation of the assessment process. We develop a framework for end-to-end quantification of uncertainty, integrating uncertainty estimates from individual stages of the assessment process. Finally, we provide research recommendations to better quantify and reduce uncertainty, to lower future ORD consenting risk. These recommendations extend beyond the UK and could improve impact assessments in other countries with different legislative frameworks.

Buyse, Jolien; Reubens, Jan; Hostens, Kris; Degraer, Steven; Goossens, Jolien; De Backer, Annelies

doi: 10.1093/icesjms/fsad179pmid: N/A

Offshore wind farms (OWFs) are expanding rapidly in the North Sea, often creating spatial conflicts with fisheries. Managing such conflicts requires knowledge on the impact of OWFs on the spatial distribution and movement behaviour of fished species. However, such knowledge is still lacking, especially for soft sediment fish such as flatfish, which are vital fisheries resources in the region. Therefore, we used acoustic telemetry to examine the spatial behaviour of European plaice in relation to an OWF and its structures. In a small study area (1.37 km2), we observed high residency for plaice around the turbines and scour protection layer (SPL), which consists of large rocks around the turbine foundation. The fish primarily resided on sandy sediments near the hard substrates, but showed a diurnal pattern of proximity to the turbine, being closer during the day. Considering their trophic ecology, these findings suggest that plaice moves towards the SPL for feeding opportunities on the hard substrate, potentially leading to increased ecological fish production within OWFs. Although most plaice moved away from the OWF in winter, likely towards spawning grounds, many exhibited high site fidelity returning to the study area after the winter migration. OWFs thus offer protection from fishing mortality as “closed” feeding grounds in spring and summer, but not during winter spawning migrations, which may result in spillover effects. These insights should inform local fisheries management in relation to plaice movement within and around OWFs.

Horwitz, Rebecca; Miles, Travis N; Munroe, Daphne; Kohut, Josh

doi: 10.1093/icesjms/fsad190pmid: N/A

The Mid-Atlantic Cold Pool is a seasonal mass of cold bottom water that extends throughout the Mid-Atlantic Bight (MAB). Formed from rapid vernal surface warming, the Cold Pool dissipates in the fall due to mixing events such as storms. The Cold Pool supports a myriad of MAB coastal ecosystems and economically valuable commercial and recreational fisheries. Offshore wind energy has been rapidly developing within the MAB in recent years. Studies in Europe demonstrate that offshore wind farms can impact ocean mixing and hence seasonal stratification; there is, however, limited information on how MAB wind development will affect the Cold Pool. Seasonal overlap between the Cold Pool and pre-construction wind lease areas at varying distances from shore in the MAB was evaluated using output from a data-assimilative ocean model. Results highlight overlap periods as well as a thermal gradient that persists after bottom temperatures warm above the threshold typically used to identify the Cold Pool. These results also demonstrate cross-shelf variability in Cold Pool evolution. This work highlights the need for more focused ocean modeling studies and observations of wind farm effects on the MAB coastal environment.