Fish distributions in a tidal channel indicate the behavioural impact of a marine renewable energy installation

Fraser, Shaun; Williamson, Benjamin; Nikora, Vladimir; Scott, Beth E.

doi:10.1016/j.egyr.2018.01.008

Cited by 31 publications

(27 citation statements)

References 18 publications

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“…Due to the seasonal variation observed, caution should be given to extrapolating any results beyond the sampled time period. Fish have been shown to potentially modify their behaviour in the presence of marine renewable devices in other development areas (Fraser et al, ; Viehman & Zydlewski, ), and so work is currently underway to understand how schools may react to an operating tidal kite.…”

Section: Discussionmentioning

confidence: 99%

“…A new aspect of tidal marine renewable energy (MRE) devices is that they have parts, or the entire structure itself, which move through the water and at speeds up to an order of magnitude greater than the prevailing currents. This presents a need to understand the potential spatial and temporal overlap between marine fauna, such as fish (Fraser, Williamson, Nikora, & Scott, ; Viehman & Zydlewski, ) and top predators such as diving seabirds and marine mammals (Williamson et al, ), and mobile MRE devices.…”

Section: Introductionmentioning

confidence: 99%

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Vertical migrations of fish schools determine overlap with a mobile tidal stream marine renewable energy device

Whitton

Jackson

Hiddink

et al. 2020

Journal of Applied Ecology

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Large increases in the generation of electricity using marine renewable energy (MRE) are planned, and assessment of the environmental impacts of novel MRE devices, such as kites, are urgently needed. A first step in this assessment is to quantify overlap in space and time between MRE devices and prey species of top predators such as small pelagic fish. Here, we quantify how the distribution of fish schools overlaps with the operational depth (20–60 m) and tidal current speeds (≥1.2–2.4 m/s) used by tidal kites, and the physical processes driving overlap. Fish schools undertake diel vertical migrations driven by the depth of light penetration into the water column, controlled by the supply of solar radiation and water column light absorption and scattering, which in turn depends on the cross‐sectional area of suspended particulate matter (SPM). Fish schools were found shallower in the morning and evening and deeper in the middle of the day when solar radiation is greatest, with the deepest depths reached during predictable bimonthly periods of lower current speeds and lower cross‐sectional area of SPM. Potential kite operations overlap with fish schools for a mean of 5% of the time that schools are present (maximum for a day is 36%). This represents a mean of 6% of the potential kite operating time (maximum for a day is 44%). These were both highest during a new moon spring tide and transitions between neap and spring tides. Synthesis and applications. Overlap of fish school depth distribution with tidal kite operation is reasonably predictable, and so the timing of operations could be adapted to avoid potential negative interactions. If all interaction between fish schools was to be avoided, the loss of operational time for tidal kites would be 6%. This information could also be used in planning the operating depths of marine renewable energy (MRE) devices to avoid or minimize overlap with fish schools and their predators by developers, and for environmental licencing and management authorities to gauge potential ecological impacts of different MRE device designs and operating characteristics.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Vertical migrations of fish schools determine overlap with a mobile tidal stream marine renewable energy device

Whitton

Jackson

Hiddink

et al. 2020

Journal of Applied Ecology

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“…The early stages of this industry and the difficulty of surveying fishes in these energetic environments necessitate empirical data. While there have been several peer-reviewed field studies in recent years that have decreased uncertainty in this area [11][12][13][14][15][16][17], many questions remain. Best practices for monitoring and detecting device effects, at the individual or array level, remain under development [18].…”

Section: Introductionmentioning

confidence: 99%

“…The near-field evasion zone (0-5 m or <2 turbine diameters from a device, mesoscale) and mid-field avoidance zone (5-100 m or >2 turbine diameters from a device, macroscale) have been proposed as the most important for assessing fish interactions with a single device [4,19]. Near-field observations have been few to date [11,13,[15][16][17] and reflect the difficulty of observation near an operating device. Mid-field effects of a deployed device on fish, if any, could involve behavior changes related to general avoidance associated with optimizing swimming speed while minimizing energetic costs [20,21].…”

Section: Introductionmentioning

confidence: 99%

“…Data can be processed with good temporal (<1 s) and vertical spatial (<1 m) resolution. Vertical resolution is critical for the assessment of fish interactions with devices because the turbines will be present in a well-defined portion of the water column [17,29]. Of similar importance, seasonal changes in abundance are related to the changing presence of different fish species and their life stages [22,[30][31][32], so relative density metrics obtained via hydroacoustics can also be used to assess the presence of fish regarding tidal, diel, and seasonal cycles [26,28,33].…”

Section: Introductionmentioning

confidence: 99%

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Changes in Relative Fish Density Around a Deployed Tidal Turbine during on-Water Activities

Staines

Zydlewski

Viehman³

2019

Sustainability

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Global interest in mitigating climate change effects is a driver for the development of renewable energy sources. In-stream tidal power, a type of marine hydrokinetic (MHK) energy uses tidal currents to generate electricity and is one example of developing a renewable energy industry. Effects and impacts on fishes in areas of tidal power development are a consideration, and presently there are many unanswered questions in this field of research. Knowledge of how fish use these areas before and after device installation is essential to informing regulators for decision-making. We attempted a Before-After-Control-Impact (BACI) study design to compare an index of fish density near and away from an MHK tidal energy device deployed in Cobscook Bay, Maine. The index was mean volume backscattering strength (Sv) obtained from 24-hour stationary, down-looking hydroacoustic surveys. Data were collected several times per year at an “impact” site within 50–75 m of a device and at a “control” site approximately 1.6 km away, both before and after turbine installation in August 2012. Fish density was lowest in March surveys and highest in May surveys at both sites. One of four comparisons (August 2011/before vs. 2012/after) indicated an interaction of fish density with turbine installation. Operational status of the installed turbine and on-water activity disturbances (e.g., industry vessel and diving activities) varied at the impact site and possibly influenced results. Lower fish densities were observed during installation and maintenance periods than during normal device operation. The effects of construction activities must be separated from the effects of a deployed device to effectively implement a statistically rigorous assessment that could separate the effects of these different activities. This parsimonious approach and results were used for permit licensing by federal and state regulatory bodies at this site and others and can be used to consider regulatory adjustments during different phases of device operation and maintenance.

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Tidal streams, fish, and seabirds: Understanding the linkages between mobile predators, prey, and hydrodynamics

et al. 2022

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Driven by the necessity to decarbonize energy sources, many countries are targeting tidal stream environments for power generation. However, these areas can act as foraging hotspots for marine top predators, such as seabirds. Thus, it is important to understand the ecological interactions influencing predator behavior and distribution in these areas, to determine the potential ecological implications of marine renewable devices. This study used concurrent observations of foraging seabirds, physical hydrodynamics, and prey presence across a tidal stream environment, before and after the installation of a commercial turbine array close to the island of Stroma, Scotland. There were three main findings: First, benthic foraging seabirds showed a clear preference for certain sections around Stroma where sandeels were detected, while pelagic foraging seabirds were seen all around Stroma. Second, there was a positive effect of water velocity on the number of pelagic foragers and common guillemots. Third, there was a positive effect of the presence of fish schools on the number of pelagic seabirds and common guillemots, in both the same and the previous transects. Thus, it is possible that seabirds target areas of predictable food sources during periods where prey might be easily accessed (e.g., periods of fast flows). Given the difference in the distribution between seabird categories, it is likely that marine renewable devices will impact each category differently. We conclude that any impact on sandbank locations, sandeels preferred habitat, due to the presence of tidal turbines is likely to alter the distribution of benthic foraging seabirds. For pelagic foraging seabirds and common guillemot, changes in prey presence and accessibility (depth and level of aggregation/disaggregation) will have a stronger effect on seabird presence. This study highlights the need to include concurrent physical and biological data when assessing the ecological impacts of tidal turbines.

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Fish distributions in a tidal channel indicate the behavioural impact of a marine renewable energy installation

Cited by 31 publications

References 18 publications

Vertical migrations of fish schools determine overlap with a mobile tidal stream marine renewable energy device

Vertical migrations of fish schools determine overlap with a mobile tidal stream marine renewable energy device

Changes in Relative Fish Density Around a Deployed Tidal Turbine during on-Water Activities

Tidal streams, fish, and seabirds: Understanding the linkages between mobile predators, prey, and hydrodynamics

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