Evaluation of Behavior and Survival of Fish Exposed to an Axial‐Flow Hydrokinetic Turbine

Abstract

Previous studies have evaluated fish injury and mortality at hydrokinetic (HK) turbines, but because these studies focused on the impacts of these turbines in situ they were unable to evaluate fish responses to controlled environmental characteristics (e.g., current velocity and light or dark conditions). In this study, we used juvenile hybrid Striped Bass (HSB; Striped Bass Morone saxatilis × White Bass M. chrysops; N = 620), Rainbow Trout Oncorhynchus mykiss (N = 3,719), and White Sturgeon Acipenser transmontanus (N = 294) in a series of laboratory experiments to (1) evaluate the ability of fish to avoid entrainment through an axial‐flow HK turbine, (2) evaluate fish injury and survival associated with turbine entrainment, and (3) compare the effects of different HK turbines on fish. We found that the probability of turbine entrainment was species dependent and highest for HSB. Across species, current velocity influenced entrainment probability. Among entrained fish, observed survival rates were generally >0.95. The probability of injury for surviving entrained fish only differed from that for nonentrained fish for Rainbow Trout and in general was not >0.20. The probability of injury following entrainment was greater only for HSB, although there were no differences in injury rates between fish that were turbine entrained and those that were not, suggesting that injuries were not turbine related. Taking turbine entrainment, survival, and injury estimates together allowed us to estimate the probability of a randomly selected fish in a population proximate to an HK turbine surviving passage or remaining uninjured after passage. For species and current velocities for which there was a significant effect due to entrainment, we estimated, for instance, that HSB had a survival probability of 0.95 and that Rainbow Trout and White Sturgeon had a >0.99 probability of survival. Similarly, by combining these estimates with those from previous studies, we derived total passage survival probabilities >0.90 but generally approaching 1.00 across different HK turbine types, fish species, and fish lengths.Received May 14, 2014; accepted October 23, 2014

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

“…In conclusion, we found no evidence that fish were regularly struck by turbine blades at the RITE site, and we believe that the likelihood is quite low based on several lines of evidence: the low probability that fish would directly encounter a turbine (Wilson et al 2007), the apparent longrange avoidance seen in this study and another study , the apparent ability of most fish to avoid rotor blades when they are encountered at close range (Amaral et al 2010(Amaral et al , 2015, and the paucity of evidence for direct blade strikes. However, based on the relative number of fish tracks identified under the different turbine conditions, the results of this study do suggest that avoidance might be occurring at a distance beyond the 10-15-m range of the DIDSON system.…”

“…One of the most important environmental issues facing the marine and hydrokinetic energy industry is whether fish and marine mammals that encounter these devices are likely to be struck and possibly injured by moving components, primarily rotating turbine blades. For hydrokinetic devices (e.g., tidal turbines) that generate energy from flowing water, this concern is greatest for large organisms because their increased length increases the probability that they will be struck as they pass through the blade-swept area (Schweizer et al 2011;Hammar et al 2015) and because their increased mass means that the force absorbed if they are struck is greater and potentially more damaging (Amaral et al 2015). Key to addressing this issue is understanding whether aquatic organisms encountering a hydrokinetic device change their swimming behavior in a way that decreases their likelihood of being struck and possibly injured by the device.…”

Long‐term effect of a tidal, hydroelectric propeller turbine on the populations of three anadromous fish species

“…Unfortunately, plans are to mass the turbines in regions of high power potential ( This mode of operation means that a 16 m diameter propeller turbine in a 5 m s −1 tidal flow will pass 45 km 3 of sea water during a 12.4 h tide cycle and the fishes and other marine animals therein will be affected by the physical changes and machinery in the draft tube if they pass through it. Potential mortalities may be lower than they are with a barrage turbine (Amaral et al, 2015) but a long-term, cumulative effect is probable. The ocean is already at or past its sustainable yield (Pauly et al, 2002;Shao, 2009) and further depletion of its resources will not improve the situation.…”

Winter and summer differences in probability of fish encounter (spatial overlap) with MHK devices

“…video [54]). However, laboratory simulations have found it difficult to make fish enter MHK turbines even in confined spaces, and have measured survival rates greater than 90% for those fish that do pass through [55,56]. These studies have not examined survival rates in the dark, which may be an important factor in turbine avoidance and evasion [47].…”