Browsing by Author "Gill, Andrew B."
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Item Open Access Assessing the cumulative environmental effects of marine renewable energy developments: establishing common ground(Elsevier, 2016-11-03) Willsteed, Edward; Gill, Andrew B.; Birchenough, S. N.; Jude, Simon R.Assessing and managing the cumulative impacts of human activities on the environment remains a major challenge to sustainable development. This challenge is highlighted by the worldwide expansion of marine renewable energy developments (MREDs) in areas already subject to multiple activities and climate change. Cumulative effects assessments in theory provide decision makers with adequate information about how the environment will respond to the incremental effects of licensed activities and are a legal requirement in many nations. In practise, however, such assessments are beset by uncertainties resulting in substantial delays during the licensing process that reduce MRED investor confidence and limit progress towards meeting climate change targets. In light of these targets and ambitions to manage the marine environment sustainably, reducing the uncertainty surrounding MRED effects and cumulative effects assessment are timely and vital. This review investigates the origins and evolution of cumulative effects assessment to identify why the multitude of approaches and pertinent research have emerged, and discusses key considerations and challenges relevant to assessing the cumulative effects of MREDs and other activities on ecosystems. The review recommends a shift away from the current reliance on disparate environmental impact assessments and limited strategic environmental assessments, and a move towards establishing a common system of coordinated data and research relative to ecologically meaningful areas, focussed on the needs of decision makers tasked with protecting and conserving marine ecosystems and services.Item Open Access Early life sensory ability—ventilatory responses of thornback ray embryos (Raja clavata) to predator-type electric fields(Wiley, 2015-10-30) Ball, Rachel Emma; Oliver, Matthew Kenneth; Gill, Andrew B.Predator avoidance is fundamental for survival and it can be particularly challenging for prey animals if physical movement away from a predatory threat is restricted. Many sharks and rays begin life within an egg capsule that is attached to the sea bed. The vulnerability of this sedentary life stage is exacerbated in skates (Rajidae) as the compulsory ventilatory activity of embryos makes them conspicuous to potential predators. Embryos can reduce this risk by mediating ventilatory activity if they detect the presence of a predator using an acute electrosense. To determine how early in embryonic life predator elicited behavioral responses can occur, the reactions of three different age groups (1/3 developed, 2/3 developed, and near hatching) of embryonic thornback rays Raja clavata were tested using predator-type electric field stimuli. Egg capsules were exposed to continuous or intermittent stimuli in order to assess varying predator-type encounter scenarios on the ventilatory behavior of different developmental stages. All embryos reacted with a “freeze response” following initial electric field (E-field) exposure, ceasing ventilatory behavior in response to predator presence, demonstrating electroreceptive functionality for the first time at the earliest possible stage in ontogeny. This ability coincided with the onset of egg ventilatory behavior and may represent an effective means to enhance survival. A continuous application of stimuli over time revealed that embryos can adapt their behavior and resume normal activity, whereas when presented intermittently, the E-field resulted in a significant reduction in overall ventilatory activity across all ages. Recovery from stimuli was significantly quicker in older embryos, potentially indicative of the trade-off between avoiding predation and adequate respiration. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 721–729, 2016Item Open Access Effects of EMFs from Undersea Power Cables on Elasmobranchs and Other Marine Species.(2011-05-31T00:00:00Z) Tricas, Timothy; Gill, Andrew B.Anthropogenic electromagnetic fields (EMFs) have been introduced into the marine environmentaround the world and from a wide variety of sources for well over a century. Despite this, littleis known about potential ecological impacts from EMFs. For decades, power transmissioncables have been installed across bays and river mouths, and connecting near-shore islands to themainland, with little consideration of possible effects to marine species from EMFs. At a time ofgreater environmental awareness, the US now faces the possibility of a new source of EMFs overa much greater extent of the seabed from offshore renewable energy facilities in coastal waters.This literature review synthesizes information on the types of power cables and models theexpected EMFs from representative cables. Available information on electro- and magnetosensitivityof marine organisms, including elasmobranchs (sharks and rays) and other fishspecies, marine mammals, sea turtles, and invertebrates is summarized and used in conjunctionwith the power cable modeling results to evaluate the level of confidence the existing state ofknowledge provides for impact assessment. Gaps in our knowledge of power cablecharacteristics and the biology needed to understand and predict impacts are summarized andform the basis of recommendations for future research priorities. Potential mitigationopportunities are described with a discussion of their potential secondary impacts as well assuggested methods for monitoring mitigation effectiveness. Finally, because interest in offshorerenewable energy has increased throughout US coastal waters, there is a concern that organismscould be exposed to multiple seabed power cables. Cumulative effects of this exposure are discussed.Item Open Access Effects of Pile-driving Noise on the Behaviour of Marine Fish(2010-03-31T00:00:00Z) Mueller-Blenkle, Christina; McGregor, Peter K.; Gill, Andrew B.; Andersson, Mathias H.; Metcalfe, Julian; Bendall, Victoria; Sigray, Peter; Wood, Daniel T.; Thomsen, FrankStudies on the effects of offshore wind farm construction on marine life have so far focussed onbehavioural reactions in porpoises and seals. The effects on fish have only very recently come intothe focus of scientists, regulators and stakeholders. Pile-driving noise during construction is ofparticular concern as the very high sound pressure levels could potentially prevent fish from reachingbreeding or spawning sites, finding food, and acoustically locating mates. This could result in longtermeffects on reproduction and population parameters. Further, avoidance reactions might result indisplacement away from potential fishing grounds and lead to reduced catches. However, reactionthresholds and therefore the impacts of pile-driving on the behaviour of fish are completely unknown.We played back pile-driving noise to cod and sole held in two large (40 m) net pens located in a quietBay in West Scotland. Movements of the fish were analysed using a novel acoustic tracking system.Received sound pressure level and particle motion were measured during the experiments.There was a significant movement response to the pile-driving stimulus in both species at relativelylow received sound pressure levels (sole: 144 – 156 dB re 1μPa Peak; cod: 140 – 161 dB re 1 μPaPeak, particle motion between 6.51x10-3 and 8.62x10-4 m/s2 peak). Sole showed a significantincrease in swimming speed during the playback period compared to before and after playback. Codexhibited a similar reaction, yet results were not significant. Cod showed a significant freezingresponse at onset and cessation of playback. There were indications of directional movements awayfrom the sound source in both species. The results further showed a high variability in behaviouralreactions across individuals and a decrease of response with multiple exposures.This study is the first to document behavioural response of marine fish due to playbacks of pile-drivingsounds. The results indicate that a range of received sound pressure and particle motion levels willtrigger behavioural responses in sole and cod. The results further imply a relatively large zone ofbehavioural response to pile-driving sounds in marine fish. Yet, the exact nature and extent of thebehavioural response needs to be investigated further. Some of our results point toward habituationto the sound.The results of the study have important implications for regulatory advice and the implementation ofmitigation measures in the construction of offshore wind farms in the UK and elsewhere. First, theconcerns raised about the potential effects of pile-driving noise on fish were well founded. Thissuggests to both regulators and developers that the costs imposed by some mitigation measures thathave so far been applied following the precautionary principle go some of the way to addressing areal problem. We also suggest that our behavioural thresholds are considered in assessments ofimpacts of offshore wind farms in the UK and elsewhere. Mitigation measures should be furtherdiscussed developed and, if meaningful, applied especially if these could lead to a reduction ofacoustic energy that is emitted into the water column.Further studies should investigate the response at critical times (e.g. mating and spawning) and theeffects of pile-driving on communication behaviour. It will also be necessary to further investigatehabituation to the sound to effectively manage effects of pile-driving sound on marine fish.Item Open Access Elasmobranch cognitive ability: using electroreceptive foraging behaviour to demonstrate learning, habituation and memory in a benthic shark(Springer Science Business Media, 2014-01-31T00:00:00Z) Kimber, Joel A.; Sims, David W.; Bellamy, Patricia H.; Gill, Andrew B.Top predators inhabiting a dynamic environment, such as coastal waters, should theoretically possess sufficient cognitive ability to allow successful foraging despite unpredictable sensory stimuli. The cognition-related hunting abilities of marine mammals have been widely demonstrated. Having been historically underestimated, teleost cognitive abilities have also now been significantly demonstrated. Conversely, the abilities of elasmobranchs have received little attention, despite many species possessing relatively large brains comparable to some mammals. The need to determine what, if any, cognitive ability these globally distributed, apex predators are endowed with has been highlighted recently by questions arising from environmental assessments, specifically whether they are able to learn to distinguish between anthropogenic electric fields and prey bioelectric fields. We therefore used electroreceptive foraging behaviour in a model species, Scyliorhinus canicula (small-spotted catshark), to determine cognitive ability by analysing whether elasmobranchs are able to learn to improve foraging efficiency and remember learned behavioural adaptations. Positive reinforcement, operant conditioning was used to study catshark foraging behaviour towards artificial, prey-type electric fields (Efields). Catsharks rewarded with food for responding to Efields throughout experimental weeks were compared with catsharks that were not rewarded for responding in order to assess behavioural adaptation via learning ability. Experiments were repeated after a 3-week interval with previously rewarded catsharks this time receiving no reward and vice versa to assess memory ability. Positive reinforcement markedly and rapidly altered catshark foraging behaviour. Rewarded catsharks exhibited significantly more interest in the electrical stimulus than unrewarded catsharks. Furthermore, they improved their foraging efficiency over time by learning to locate and bite the electrodes to gain food more quickly. In contrast, unrewarded catsharks showed some habituation, whereby their responses to the electrodes abated and eventually entirely ceased, though they generally showed no changes in most foraging parameters. Behavioural adaptations were not retained after the interval suggesting learned behaviour was not memorised beyond the interval. Sequences of individual catshark search paths clearly illustrated learning and habituation behavioural adaptation. This study demonstrated learning and habituation occurring after few foraging events and a memory window of between 12 h and 3 weeks. These cognitive abilities are discussed in relation to diet, habitat, ecology and anthropogenic Efield sources. © 2013 Springer-Verlag Berlin Heidelberg.Item Open Access Environmental and ecological effects of ocean renewable energy development: a current synthesis(The Oceanographic Society; 1999 / The Oceanography Society (TOS), 2010-12-31T00:00:00Z) Boehlert, G. W.; Gill, Andrew B.Marine renewable energy promises to assist in the effort to reduce carbon emissions worldwide. As with any large-scale development in the marine environment, however, it comes with uncertainty about potential environmental impacts, most of which have not been adequately evaluated—in part because many of the devices have yet to be deployed and tested. We review the nature of environmental and, more specifically, ecological effects of the development of diverse types of marine renewable energy—covering marine wind, wave, tidal, ocean current, and thermal gradient—and discuss the current state of knowledge or uncertainty on how these effects may be manifested. Many of the projected effects are common with other types of development in the marine environment; for example, additional structures lead to concerns for entanglement, habitat change, and community change. Other effects are relatively unique to marine energy conversion, and specific to the type of energy being harnessed, the individual device type, or the reduction in energy in marine systems. While many potential impacts are unavoidable but measurable, we would argue it is possible (and necessary) to minimize others through careful device development and site selection; the scale of development, however, will lead to cumulative effects that we must understand to avoid environmental impacts. Renewable energy developers, regulators, scientists, engineers, and ocean stakeholders must work together to achieve the common dual objectives of clean renewable energy and a healthy marine environment. - See more at: http://www.tos.org/oceanography/archive/23-2_boehlert.html#sthash.MBJIR5sa.dpufItem Open Access Impact of deforestation on habitat connectivity thresholds for large carnivores in tropical forests(Springer, 2017-07-13) Zemanova, Miriam A.; Perotto-Baldivieso, Humberto L.; Dickins, Emily L.; Gill, Andrew B.; Leonard, John P.; Wester, David B.Introduction Deforestation significantly impacts large carnivores that depend on large tracts of interconnected forest habitat and that are sensitive to human activities. Understanding the relationship between habitat use and spatial distribution of such species across human modified landscapes is critical when planning effective conservation strategies. This study assessed the presence of potential landscape connectivity thresholds resulting from habitat fragmentation associated with different deforestation patterns using a scale-based approach that links species-specific home ranges with the extent of anthropogenic activities. The objectives were (1) to quantify the spatial and temporal distribution of natural vegetation for five common deforestation patterns and (2) to evaluate the connectivity associated with these patterns and the existence of potential thresholds affecting jaguar dispersal. The Bolivian lowlands, located within jaguar conservation units, were analysed with landscape metrics to capture the spatial and temporal changes within deforested areas and to determine potential impact on jaguar connectivity and connectivity thresholds for dispersal. Results Over the period of 1976–2005, the amount of natural vegetation has decreased by more than 40% in all locations with the biggest changes occurring between 1991 and 2000. Landscape spatial structure around jaguar locations showed that jaguars used areas with mean proportion of natural areas = 83.14% (SE = 3.72%), mean patch density = 1.16 patches/100 ha (SE = 0.28 patches/100 ha), mean patch area = 616.95 ha (SE = 172.89 ha) and mean edge density = 705.27 m/ha (SE = 182.19 m/ha).We observed strong fragmentation processes in all study locations, which has resulted in the connectivity of jaguar habitat decreasing to <20% by 2005. A connectivity threshold zone was observed when the proportion of natural vegetation was less than 58.4% (SE = 1.3). Conclusions Assessing fragmentation and connectivity for carnivores within the extent of human-modified landscapes proved to be an effective way to understand the changes caused by deforestation and their potential effects on large carnivore habitats. Our study highlights the importance of scale-based approaches for assessing current conservation challenges to protect large carnivores.Item Open Access Linking ecosystem services with epibenthic biodiversity change following installation of offshore wind farms(Elsevier, 2018-09-01) Causon, Paul D.; Gill, Andrew B.The growing awareness of climate change and the recognised need to secure energy production has been a driving force behind the expansion of the offshore wind industry across the world. Benefits from offshore wind farms (OWFs) may extend further than low CO2 energy production. Wind turbine substructures introduce hard surfaces that are rapidly colonised by epibenthic marine organisms, altering biomass and biodiversity within the local ecosystem. Biodiversity plays a critical role in supporting ecosystem processes and functions that maintain ecosystem services. As offshore wind development continues to grow and modify marine habitats, changes in biodiversity could affect the provision of ecosystem services. In this context, this review sets out to capture the current understanding of epibenthic biodiversity change following the installation of OWFs and attempt to link these changes in biodiversity with marine ecosystem services through the associated processes and functions.Item Open Access Literature review on the potential effects of electromagnetic fields and subsea noise from marine renewable energy developments on Atlantic salmon, sea trout and European eel. Scottish Natural Heritage Commissioned Report(2011-02-28T00:00:00Z) Gill, Andrew B.; Bartlett, Mark D.Background This report reviews the current state of knowledge with regard to the potential for three fish species of conservation importance, namely Atlantic salmon (Salmo salar), sea trout (Salmo trutta) and European eel (Anguilla anguilla), to be affected by marine renewable energy developments (MRED). The focus is on marine wave and tidal power developments that will generate electricity offshore, which will then be transferred to land by subsea cable. During construction and operation, the marine renewable energy (MRE) devices are expected to cause a number of disturbances to the marine environment including electromagnetic fields (EMF) emissions and subsea sounds (generally referred to as ‘noise'). Such disturbances were assessed to meet the following aims: To determine the current understanding of the effects of EMFs and noise associated with the installation and operation of MREDs, on the behaviour of three species: S. salar, S. trutta and A. anguilla. To determine the gaps in current knowledge and identify research requirements.Main findings The availability and quality of the information on which to base the review was found to be limited with respect to all aspects of the fishes migratory behaviour and activity, both before and after MRE development; this makes it difficult to establish cause and effect. The main findings were: S. salar and A. anguilla can use the earth's magnetic field for orientation and direction finding during migrations. S. trutta juveniles, and close relatives of S. trutta, respond to both the earth's magnetic field and artificial magnetic fields. Current knowledge suggests that EMFs from subsea cables and cabling orientation may interact with migrating eels (and possibly salmonids) if their migration or movement routes take them over the cables, particularly in shallow waters (<20m).The effect, if any, could be a relatively trivial temporary change in swimming direction, or potentially a more serious avoidance response or delay to migration. Whether this will represent a biologically significant effect cannot yet be determined. S. salar, S. trutta and A. anguilla are likely to encounter EMF from subsea cables either during the adult movement phases of life or their early life stages during migration within shallow, coastal waters adjacent to the natal rivers. The subsea noise from MRE devices has not been suitably characterised to determine its acoustic properties and propagation through the coastal waters. MREDs that require pile driving during construction appear to be the most relevant to consider, in addition to the time scale over which pile driving is carried out, for the species under investigation. In the absence of a clear understanding of their response to subsea noise, the specific effects on S. salar, S. trutta and A. anguilla remain very difficult to determine for Scottish waters in relation to tidal and wave power. Based on the studies reviewed, it is suggested that fish that receive high intensity sound pressures (i.e. close proximity to the MRED construction) may be negatively impacted to some degree, whereas those at distances of 100's to 1000's of metres may exhibit behaviour responses, the impact of which is unknown and will be dependent on the received sound. During operation there may be more subtle behavioural effects that should be considered over the life time of the MRED. Whether these effects will represent biologically significant impacts cannot yet be determined. The current assumptions of limited effects are built on an incomplete understanding of how the three species move around their environment and interact with natural and anthropogenic EMF and subsea noise. A number of gaps in understanding exist, principally whether S. salar, S. trutta and A. anguilla respond to the EMF and/or the noise associated with MREDs in Scottish waters. A number of suggestions for specific studies are highlighted in the final section of the report.Item Open Access Non-consumptive effects of native and invasive predators on juvenile Caribbean parrotfish(Springer, 2016-04-30) Eaton, Lewis; Sloman, Katherine A.; Wilson, Rod W.; Gill, Andrew B.; Harborne, Alastair R.Non-consumptive effects of predators can have important impacts on aquatic food webs, but there are few data on how predators change the behaviour of Caribbean reef fishes. Such changes may include behavioural responses to the invasive predatory lionfish (Pterois volitans/P. miles). This study used an aquarium experiment to examine the behaviour of herbivorous parrotfish (Scarus iseri) in the absence of other fish (control), with a non-piscivore present, and with a predatory threat from a native grouper or lionfish. Treatments were repeated with and without additional parrotfish shelters to examine the potential effects of degraded reefs (loss of refuges). Using video, parrotfish behaviours (sheltering, swimming in open areas, foraging, aggressive conspecific interactions, bite rates, and shoaling behaviour) were recorded for groups of four parrotfish. Compared to the control, the average number of parrotfish hiding was reduced by 65 % and foraging shoals were 10 % larger when threatened by grouper, likely as a specific response to an ambush predator. When exposed to lionfish, parrotfish reduced their bite rates by 50 %, possibly to be more vigilant of this predator’s unique stalking behaviour. The absence of additional shelter had limited effects although parrotfish formed 10 % larger shoals when swimming in open water, potentially as a defensive behaviour because of a perceived lack of refuges. The reduction in parrotfish bite rates caused by lionfish may have important demographic consequences. Furthermore, parrotfishes are important grazers of macroalgae, and these behavioural changes may exacerbate the direct effects of lionfish predation and potentially affect reef benthic dynamics.Item Open Access Offshore renewable energy: ecological implications of generating electricity in the coastal zone.(Blackwell Publishing Ltd, 2005-01-01T00:00:00Z) Gill, Andrew B.Global scale environmental degradation and its links with non-renewable fossil fuels have lead to an increasing interest in generating electricity from renewable energy resources. Much of this interest centres on offshore renewable energy developments (OREDs). The large scale of proposed OREDs will add to the existing human pressures on coastal ecosystems, therefore any ecological costs and benefits must be determined.Item Open Access Structuring cumulative effects assessments to support regional and local marine management and planning obligations(Elsevier, 2018-09-22) Willsteed, Edward A.; Birchenough, Silvana N. R.; Gill, Andrew B.; Jude, SimonCumulative effects assessments are a legal requirement in many jurisdictions and are key to informing marine policy. However, practice does not yet deliver fit-for-purpose assessments relative to sustainable development and environmental protection obligations. The complexity of cumulative effect questions, which are embedded in complex social-ecological systems, makes multiple, methodologically diverse assessments a necessity. Using the expansion of marine renewable energy developments in European Union waters as a case study, this paper explores how social-ecological systems thinking and cumulative effects assessment theory can combine to structure CEAs that better support the management and regulation of maritime activities at regional scales. A general perspective for cumulative effects assessment is proposed to remove ambiguity of intent and to orient assessments towards a common objective. Candidate principles for practice are presented for consideration. These principles are integrated into a stepped assessment approach that seeks to improve cumulative effects assessments of localised activities relative to the information needs of decision-makers implementing the ecosystem approach.Item Open Access Turning off the DRIP (‘Data-rich, information-poor’) – rationalising monitoring with a focus on marine renewable energy developments and the benthos(Elsevier, 2017-03-04) Wilding, Thomas A.; Gill, Andrew B.; Boon, Arjen; Sheehan, Emma; Dauvin, Jean–Claude; Pezy, Jean-Philippe; O’Beirn, Francis; Janas, Urszula; Rostin, Liis; De Mesel, IlseMarine renewable energy developments (MREDs) are rapidly expanding in size and number as society strives to maintain electricity generation whilst simultaneously reducing climate-change linked CO2 emissions. MREDs are part of an ongoing large-scale modification of coastal waters that also includes activities such as commercial fishing, shipping, aggregate extraction, aquaculture, dredging, spoil-dumping and oil and gas exploitation. It is increasingly accepted that developments, of any kind, should only proceed if they are ecologically sustainable and will not reduce current or future delivery of ecosystem services. The benthos underpins crucial marine ecosystem services yet, in relation to MREDs, is currently poorly monitored: current monitoring programmes are extensive and costly yet provide little useful data in relation to ecosystem-scale-related changes, a situation called ‘data-rich, information-poor’ (DRIP). MRED –benthic interactions may cause changes that are of a sufficient scale to change ecosystem services provision, particularly in terms of fisheries and biodiversity and, via trophic linkages, change the distribution of fish, birds and mammals. The production of DRIPy data should be eliminated and the resources used instead to address relevant questions that are logically bounded in time and space. Efforts should target identifying metrics of change that can be linked to ecosystem function or service provision, particularly where those metrics show strongly non-linear effects in relation to the stressor. Future monitoring should also be designed to contribute towards predictive ecosystem models and be sufficiently robust and understandable to facilitate transparent, auditable and timely decision-making.