In-situ ecological interactions with a deployed tidal energy device; an observational pilot study

Broadhurst, Melanie; Barr, Sue

doi:10.1016/j.ocecoaman.2014.06.008

Cited by 33 publications

(25 citation statements)

References 43 publications

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“…For example, Urmy and Horne [19] limited their analysis of nekton vertical distribution to samples collected near noon, which reduced variation introduced by the diel vertical migration of organisms. At tidal energy sites, 24-hr surveys would be well-suited to characterizing the strong variation occurring over 12-hr and 24-hr cycles (and sometimes 6-hr cycles [48]). These surveys could then be spaced over time to characterize the longer-term cycles, such as seasonal changes.…”

Section: Discussionmentioning

confidence: 99%

Multi-scale temporal patterns in fish presence in a high-velocity tidal channel

Viehman

Zydlewski

2017

PLoS ONE

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The natural variation of fish presence in high-velocity tidal channels is not well understood. A better understanding of fish use of these areas would aid in predicting fish interactions with marine hydrokinetic (MHK) devices, the effects of which are uncertain but of high concern. To characterize the patterns in fish presence at a tidal energy site in Cobscook Bay, Maine, we examined two years of hydroacoustic data continuously collected at the proposed depth of an MHK turbine with a bottom-mounted, side-looking echosounder. The maximum number of fish counted per hour ranged from hundreds in the early spring to over 1,000 in the fall. Counts varied greatly with tidal and diel cycles in a seasonally changing relationship, likely linked to the seasonally changing fish community of the bay. In the winter and spring, higher hourly counts were generally confined to ebb tides and low slack tides near sunrise and sunset. In summer and fall of each year, the highest fish counts shifted to night and occurred during ebb, low slack, and flood tides. Fish counts were not linked to current speed, and did not decrease as current speed increased, contrary to observations at other tidal power sites. As fish counts may be proportional to the encounter rate of fish with an MHK turbine at the same depth, highly variable counts indicate that the risk to fish is similarly variable. The links between fish presence and environmental cycles at this site will likely be present at other locations with similar environmental forcing, making these observations useful in predicting potential fish interactions at tidal energy sites worldwide.

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Section: Discussionmentioning

confidence: 99%

Multi-scale temporal patterns in fish presence in a high-velocity tidal channel

Viehman

Zydlewski

2017

PLoS ONE

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“…Video evaluations of a vertical-axis turbine off the coast of Mozambique identified near-field avoidance by most fish; for the few fish that passed through the rotors, there was no evidence of blade strike (Hammar et al 2013). Broadhurst et al (2014) also used a video system to monitor fish abundance around a test turbine in the Orkney Isles, Scotland, and reported that schools often gathered around the operating device, perhaps for protection or feeding. Analysis of a horizontal-axis turbine in the East River, New York, by using a split-beam hydroacoustics system concluded that fish abundance in the deployment zone varied significantly with seasonal migrations, was greatest during slack tide, was equivalent between day and night periods, and was lower than the abundance in nearshore areas (Verdant Power 2010).…”

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confidence: 99%

Hydroacoustic Assessment of Behavioral Responses by Fish Passing Near an Operating Tidal Turbine in the East River, New York

et al. 2017

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An important environmental issue facing the marine and hydrokinetic energy industry is whether fish that encounter underwater energy devices are likely to be struck and injured by moving components, primarily rotating turbine blades. The automated analysis of nearly 3 weeks of multibeam hydroacoustics data identified about 35,000 tracks of fish passing a tidal turbine in the East River, New York. These tracks included both individual fish and schools during periods with the turbine absent, the turbine present and operating, and the turbine present but not operating. The density of fish in the sampled area when the turbine was absent was roughly twice the density observed when the turbine was in place, particularly when the turbine was operating. This suggests that some avoidance occurred before fish were close enough to the turbine to be observed by the hydroacoustics system. Various measures of swimming behavior (direction, velocity, and linearity) were calculated for each track and evaluated for indication of behavioral responses to turbine presence and operation. Fish tracks were grouped based on tidal cycle, current velocity, and swimming direction and were evaluated with respect to turbine presence and operation and with respect to distance from the turbine. Nonparametric tests (Kolmogorov–Smirnov test) and multivariate analysis (canonical discriminant analysis) found significant differences among groups with respect to turbine presence and operation, suggesting that some fish responded to the turbine by adjusting swimming behavior, such as making small adjustments to swimming direction and velocity as they passed near the turbine. We found no evidence that fish were being struck by rotating blades, but there did appear to be large‐scale avoidance initiated out of the range of the hydroacoustics detection system. More study is needed to determine whether such avoidance behavior has significant ramifications for normal fish movement patterns, bioenergetics, seasonal migrations, and predator exposure. Received October 28, 2016; accepted May 29, 2017 Published online August 2, 2017

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“…Cameras mounted below or above the water can also monitor the effect of operational energy convertors on fish, mammal, and bird behavior (eg Broadhurst et al . ).…”

Section: Ecosystem‐ and Population‐level Monitoringmentioning

confidence: 97%

Camera technology for monitoring marine biodiversity and human impact

Bicknell

Godley

Sheehan

et al. 2016

Frontiers in Ecol & Environ

135

106

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Human activities have fundamentally altered the marine environment, creating a need for effective management in one of Earth's most challenging habitats. Remote camera imagery has emerged as an essential tool for monitoring at all scales, from individuals to populations and communities up to entire marine ecosystems. Here we review the use of remote cameras to monitor the marine environment in relation to human activity, and consider emerging and potential future applications. Rapid technological advances in equipment and analytical tools influence where, why, and how remote camera imagery can be applied. We encourage the inclusion of cameras within multi‐method and multi‐sensor approaches to improve our understanding of ecosystems and help manage human activities and minimize impacts.

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In-situ ecological interactions with a deployed tidal energy device; an observational pilot study

Cited by 33 publications

References 43 publications

Multi-scale temporal patterns in fish presence in a high-velocity tidal channel

Multi-scale temporal patterns in fish presence in a high-velocity tidal channel

Hydroacoustic Assessment of Behavioral Responses by Fish Passing Near an Operating Tidal Turbine in the East River, New York

Camera technology for monitoring marine biodiversity and human impact

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