Juvenile Salmon Acoustic Telemetry System Research Articles

A large dataset of detection and submeter-accurate 3-D trajectories of juvenile Chinook salmon

Acoustic telemetry has been used extensively to study the behavior of aquatic animals. The Juvenile Salmon Acoustic Telemetry System (JSATS) is one such system; it was developed for studying juvenile salmonids but has been used to study numerous species. A recent innovation of the JSATS system is an acoustic transmitter that is small enough to be implanted through injection or small incision that doesn’t require sutures. Use of the JSATS system involves deploying cabled acoustic receivers at hydroelectric dams, or other structures, and autonomous acoustic receivers in free-flowing sections of a river. The raw detections from acoustic-tagged fish are processed to remove potential false positives. The clean detections (5,147,996 total) are used to generate detection events and to compute 3-D trajectories (403,900 total), which are used to assign fish to a passage route through a dam. Controlled field testing involving a high-accuracy Global Positioning System receiver is done to validate the submeter accuracy of the trajectories. The JSATS dataset could be reused for expanding the understanding of near-dam fish behavior.

High precision 3-D coordinates for JSATS tagged fish in an acoustically noisy environment

BackgroundAcoustic tagging methods have been used to track fish for some time. Multiple systems have been developed, including those that give researchers the ability to position fish in three dimensions and time. However, proprietary positioning methods have suffered from a lack of transparency. The U.S. Department of Energy and the U.S. Army Corps of Engineers developed the Juvenile Salmon Acoustic Telemetry System (JSATS) to monitor the survivability of juvenile salmonids as they migrate downstream. With much smaller tags and high ping rates, JSATS positioning studies should be more prevalent, but implementation is difficult and often out of reach for small budget-minded studies. This study implemented a small scale JSATS positioning study using relatively inexpensive, autonomous, independent receivers. We will show that proper synchronization of the transmissions and elimination of multipath allows the positions of a smolt to be determined in three spatial dimensions over time with high precision.ResultsTracking of 172 tagged smolts produced a total of nearly 2,00,000 positions. We compared the performance of four different supervised machine learning classifiers (Support Vector Classifier (SVC), Gaussian Naïve Bayes (NB), Classification Tree (CART), and K-Nearest Neighbor (KNN). All algorithms performed well with high accuracy and precision, but recall rates decreased with distance from the source. The SVC and KNN were least restrictive in practice. Overall, the SVC had the longest time to solve.ConclusionPositions determined from fish outside of the convex hull of the hydrophones were effectively being extrapolated, while positions determined from within the convex hull nearly always met or exceeded 1-m precision. Having stationary submerged hydrophones was necessary to produce three-dimensional positions. The main technical advances presented are the hydrophone-clock synchronization scheme and the multipath rejection scheme, which found the best multipath classifier to be the K-Nearest Neighbor. Neither algorithm was capable of alleviating close proximity detection interference (CPDI), suggesting the need to reposition receivers from reflective surfaces or install baffling.

Factors affecting detection probability and range of transmitters and receivers designed for the Juvenile Salmon Acoustic Telemetry System

Acoustic telemetry allows collection of data on the movement and survival of fish and other aquatic organisms. The passive form of this technology uses transmitters (tags) and fixed receivers to record when an organism is present at a given location. Understanding and interpretation of these data depends on knowledge of the detection range and detection probability of the receivers. This study examines factors affecting performance of tags and receivers designed for the Juvenile Salmon Acoustic Telemetry System (JSATS) at a location in the Sacramento River in CA, USA. A group of tags (n = 13) of two power output levels, each transmitting a unique code at five second intervals, were manually moved past a set of two fixed receivers in upstream and downstream directions along transects of different distances from the receivers at two different speeds. The factors that significantly affected detection probability were tag orientation and tag movement direction. Tag orientation had the largest effect on detection probability, with higher detection rates when the tag’s piezoelectric transducer was directed towards the receiver. Detection probability (proportion of transmissions detected) was 30–50% out to 160 m. Detection efficiency (proportion of tags regarded as present) was 99–100% when tags passed within 25 m and 84–96% within 135 m of a receiver. These results have implications for the design and interpretation of acoustic tracking studies and the orientation of transmitters when implanted into fish.

Survival, Tag Retention, Growth, and Wound Healing of Juvenile Chinook Salmon (Oncorhynchus tshawytscha) Surgically Implanted with a Dummy Acoustic Tag

Tag effect studies are paramount in interpreting the results of survival studies. The objective of this study was to analyze the influence of tag implantation and tag burden on the survival, tag retention, growth, and wound healing of juvenile Chinook Salmon 7.8 ± 0.9 g initial weight. Fish were obtained from the Merced River Hatchery, held for 7 d, and then surgically implanted with Juvenile Salmon Acoustic Telemetry System (JSATS) SS300 dummy tags (0.3 g in air). Tag burden ranged from 2.9–4.8% (3.86 ± 0.43%, mean ± standard deviation). Weight and fork length were taken immediately before tag implantation. All fish (i.e., control and dummy-tagged) were also implanted with a visible implant alpha tag next to the dorsal insertion. Control and dummy-tagged fish were held in a single tank for 30 d. Any fish that died during the 30-d period were noted. At the end of the holding period, all fish were euthanized, weighed, measured, and necropsied. All dummy-tagged fish retained their dummy tag, and survival rates between the two groups were similar. Wound healing was also similar across the range of tag burdens analyzed. Specific growth rates, however, differed significantly between the two groups, with control fish growing at a rate of 1.08 ± 0.38% d− 1 compared to 0.55 ± 0.48 % d− 1 in dummy-tagged fish (P < 0.001). Tag burdens and specific growth rates for dummy-tagged fish (P = 0.961) did not correlate, nor did initial weight and specific growth rate for control (P = 0.363) or dummy-tagged (P = 0.983) fish. The cause of the decreased growth rate in dummy-tagged fish remains unknown. Determining the cause of decreased growth in tagged juvenile Chinook Salmon, and how that decreased growth may influence survival in the wild, should be investigated further.

Three-dimensional migration behavior of juvenile salmonids in reservoirs and near dams

To acquire 3-D tracking data on juvenile salmonids, Juvenile Salmon Acoustic Telemetry System (JSATS) cabled hydrophone arrays were deployed in the forebays of two dams on the Snake River and at a mid-reach reservoir between the dams. The depth distributions of fish were estimated by statistical analyses performed on large 3-D tracking data sets from ~33,500 individual acoustic tagged yearling and subyearling Chinook salmon and juvenile steelhead at the two dams in 2012 and subyearling Chinook salmon at the two dams and the mid-reach reservoir in 2013. This research investigated the correlation between vertical migration behavior and passage routes. The depth distributions of fish within the forebays of the dams were significantly different from fish passing the mid-reach reservoir. Fish residing deeper in the forebay tended to pass the dam using deeper powerhouse routes. This difference in depth distributions indicated that the depth distribution of fish at the mid-reach reservoir was not related to behaviors of fish passing through certain routes of the adjacent dams. For fish that were detected deeper than 17.5 m in the forebays, the probability of powerhouse passage (i.e., turbine) increased significantly. Another important finding was the variation in depth distributions during dam passage associated with the diel period, especially the crepuscular periods.

Movement and Survival of Wild Chinook Salmon Smolts from Butte Creek During Their Out‐Migration to the Ocean: Comparison of a Dry Year versus a Wet Year

AbstractCalifornia's Central Valley (CCV) Chinook Salmon Oncorhynchus tshawytscha stocks have declined substantially since the mid‐1800s, with most listed as threatened or endangered or heavily supplemented by hatcheries. As the largest population of CCV wild spring‐run Chinook Salmon, Butte Creek fish are an important source for promoting life history diversity in the CCV Chinook Salmon community. However, little information exists on Butte Creek juvenile mortality during out‐migration to the ocean, which is considered a critical phase in the overall population dynamics. We used the Juvenile Salmon Acoustic Telemetry System to track the movement of individual fish, and we used a mark–recapture modeling framework to estimate survival of migrating wild Chinook Salmon smolts from lower Butte Creek to ocean entry at the Golden Gate Bridge. Survival and migration varied significantly among years; in 2015, which was a dry year, Chinook Salmon smolts migrated more slowly throughout their migratory corridor and exhibited lower survival than in a wetter year (2016); among locations, fish migrated faster and experienced higher survival in the lower Sacramento River than in the Sutter Bypass and the Sacramento–San Joaquin River Delta. Our data suggest that higher flow at release and larger fish lengths both resulted in increased survival. Our findings shed light on a critical phase of wild spring‐run juvenile Chinook Salmon dynamics and could help to inform future restoration and management projects that would improve the survival and abundance of the CCV spring‐run Chinook Salmon populations.

Performance of an acoustic telemetry system in a large fishway

The ability to track fish in the vicinity of dams and detect the presence of fish in fishways (also referred to as fish ladders) is critical to understanding the migration biology of upstream migrating fish and their passage success. Acoustic telemetry provides a valuable method within the telemetry toolbox, but has rarely been used in noisy, constrained, swift-flowing, and air-entrained environments such as fishways because of the perceived limitations of acoustic telemetry in such environments relative to other techniques such as radio telemetry. However, there have been no published studies that represent systematic evaluations of both detection efficiency based on number of transmitted signals and detection probabilities based on number of fish detected in fishways for acoustic telemetry. As such, the efficacy of acoustic telemetry in a fishway was evaluated using both controlled field experiments and movements of live fish at the Wanapum Dam fishway on the Columbia River in Washington State. In this study, the Juvenile Salmon Acoustic Telemetry System (JSATS) was selected because of its high carrier frequency (416.7 kHz) and short signal duration yielding good system resilience in shallow, noisy, and constrained environments. Detection efficiencies from the controlled field experiments were over 80 % (mean ± standard error (SE) = 85 ± 2 %) for most locations within the fishway at Wanapum Dam. Detection efficiency was nearly 100 % (mean ± SE = 97 ± 1 %) in the fishway entrance when the transmitters (also referred to as tags) were within 10 m of the hydrophones. The detection probabilities for the live fish experiment were 100 % at all deployment locations. This study suggests that a 416.7-kHz acoustic telemetry system with binary phase shift-keyed encoding is capable of reliably detecting fish within a large fishway, thus providing a reliable tool to enable researchers to understand and study fish behavior and their fate near and in fishways.

Three-dimensional tracking of juvenile salmon at a mid-reach location between two dams

Evaluating fish behavior and migration in response to environmental changes is a fundamental component of fisheries research and recovery of freshwater ecosystems. While spatial distribution and behavior of fishes has been well studied around hydropower facilities, little research has been conducted at a mid-reach location between two dams. The Juvenile Salmon Acoustic Telemetry System (JSATS) cabled receiver system was developed and employed as a reference sensor network for detecting and tracking juvenile salmon in the Columbia River Basin. To supplement acquisition of detection and three-dimensional (3-D) tracking data to estimate survival and fish behavior in the forebays of Little Goose and Lower Monumental dams on the Snake River in eastern Washington State, a mid-reach location was needed to investigate the spatial distribution of migrating juvenile salmon in open-water conditions between the two dams. Lyons Ferry Bridge on State Route 261 at the confluence of the Snake and Palouse Rivers was chosen as the mid-reach location. A JSATS-cabled receiver system configuration was successfully designed and deployed from the bridge's pier structure. Theoretical analysis confirmed the functionality and precision of the deployment design. Validation tests demonstrated sub-meter accuracy of 3-D tracking up to a horizontal distance of 50m upstream and downstream from the Lyons Ferry Bridge piers. Detection and tracking probabilities of the LFB cabled array were estimated to be 99.98% from field application. This research provided a detailed description of acoustic telemetry system deployment and 3-D tracking as guidance for better understanding of fish migration behavior as they pass through dams and continue downstream through the river between dams.

Migration depth and residence time of juvenile salmonids in the forebays of hydropower dams prior to passage through turbines or juvenile bypass systems: implications for turbine-passage survival.

Little is known about the three-dimensional depth distributions in rivers of individually marked fish that are in close proximity to hydropower facilities. Knowledge of the depth distributions of fish approaching dams can be used to understand how vulnerable fish are to injuries such as barotrauma as they pass through dams. To predict the possibility of barotrauma injury caused by pressure changes during turbine passage, it is necessary to understand fish behaviour relative to acclimation depth in dam forebays as they approach turbines. A guiding study was conducted using high-resolution three-dimensional tracking results of salmonids implanted with Juvenile Salmon Acoustic Telemetry System transmitters to investigate the depth distributions of subyearling and yearling Chinook salmon (Oncorhynchus tshawytscha) and juvenile steelhead (Oncorhynchus mykiss) passing two dams on the Snake River in Washington State. Multiple approaches were evaluated to describe the depth at which fish were acclimated, and statistical analyses were performed on large data sets extracted from ∼28 000 individually tagged fish during 2012 and 2013. Our study identified patterns of depth distributions of juvenile salmonids in forebays prior to passage through turbines or juvenile bypass systems. This research indicates that the median depth at which juvenile salmonids approached turbines ranged from 2.8 to 12.2 m, with the depths varying by species/life history, year, location (which dam) and diel period (between day and night). One of the most enlightening findings was the difference in dam passage associated with the diel period. The amount of time that turbine-passed fish spent in the immediate forebay prior to entering the powerhouse was much lower during the night than during the day. This research will allow scientists to understand turbine-passage survival better and enable them to assess more accurately the effects of dam passage on juvenile salmon survival.

A 3D approximate maximum likelihood solver for localization of fish implanted with acoustic transmitters.

Better understanding of fish behavior is vital for recovery of many endangered species including salmon. The Juvenile Salmon Acoustic Telemetry System (JSATS) was developed to observe the out-migratory behavior of juvenile salmonids tagged by surgical implantation of acoustic micro-transmitters and to estimate the survival when passing through dams on the Snake and Columbia Rivers. A robust three-dimensional solver was needed to accurately and efficiently estimate the time sequence of locations of fish tagged with JSATS acoustic transmitters, to describe in sufficient detail the information needed to assess the function of dam-passage design alternatives. An approximate maximum likelihood solver was developed using measurements of time difference of arrival from all hydrophones in receiving arrays on which a transmission was detected. Field experiments demonstrated that the developed solver performed significantly better in tracking efficiency and accuracy than other solvers described in the literature.

Feasibility of Tracking Fish with Acoustic Transmitters in the Ice Harbor Dam Tailrace

The Juvenile Salmon Acoustic Telemetry System (JSATS) has been used at many dams but has never been deployed in the near-dam tailrace environment. The use of JSATS in the tailrace is of interest to fishery managers to evaluate downstream passage behavior of juvenile salmonids and dam approach behavior of upstream migrating adult salmon and lamprey. The acoustic noise level and detection range of JSATS were studied to determine the feasibility of deploying JSATS in the Ice Harbor Dam tailrace. The noise level measured from the powerhouse deck was less than 104 dB re 1 μPa except for the turbine outlet near the spillway, and 350 m downstream of the dam, the noise level was less than 106 dB. The measured noise levels would allow a theoretical detection range of 100 m to 350 m and 85 m to 320 m, respectively. Validation experiments showed that the detection range is 113 to 184 m using hydrophones deployed from the powerhouse deck and 148 m using hydrophones deployed 500 m downstream of the dam.

Micro-battery Development for Juvenile Salmon Acoustic Telemetry System Applications

The Endangered Species Act requires actions that improve the passage and survival rates for migrating salmonoids and other fish species that sustain injury and mortality when passing through hydroelectric dams. To develop a low-cost revolutionary acoustic transmitter that may be injected instead of surgically implanted into the fish, one major challenge that needs to be addressed is the micro-battery power source. This work focuses on the design and fabrication of micro-batteries for injectable fish tags. High pulse current and required service life have both been achieved as well as doubling the gravimetric energy density of the battery. The newly designed micro-batteries have intrinsically low impedance, leading to significantly improved electrochemical performances at low temperatures as compared with commercial SR416 batteries. Successful field trial by using the micro-battery powered transmitters injected into fish has been demonstrated, providing an exemplary model of transferring fundamental research into practical devices with controlled qualities.

A Field Evaluation of an External and Neutrally Buoyant Acoustic Transmitter for Juvenile Salmon: Implications for Estimating Hydroturbine Passage Survival

Turbine-passed fish are exposed to rapid decreases in pressure which can cause barotrauma. The presence of an implanted telemetry tag increases the likelihood of injury or death from exposure to pressure changes, thus potentially biasing studies evaluating survival of turbine-passed fish. Therefore, a neutrally buoyant externally attached tag was developed to eliminate this bias in turbine passage studies. This new tag was designed not to add excess mass in water or take up space in the coelom, having an effective tag burden of zero with the goal of reducing pressure related biases to turbine survival studies. To determine if this new tag affects fish performance or susceptibility to predation, it was evaluated in the field relative to internally implanted acoustic transmitters (JSATS; Juvenile Salmon Acoustic Telemetry System) used widely for survival studies of juvenile salmonids. Survival and travel time through the study reach was compared between fish with either tag type in an area of high predation in the Snake and Columbia rivers, Washington. An additional group of fish affixed with neutrally-buoyant dummy external tags were implanted with passive integrated transponder (PIT) tags and recovered further downstream to assess external tag retention and injury. There were no significant differences in survival to the first detection site, 12 river kilometers (rkm) downstream of release. Travel times were also similar between groups. Conversely, externally-tagged fish had reduced survival (or elevated tag loss) to the second detection site, 65 rkm downstream. In addition, the retention study revealed that tag loss was first observed in fish recaptured approximately 9 days after release. Results suggest that this new tag may be viable for short term (<8 days) single-dam turbine-passage studies and under these situations, may alleviate the turbine passage-related bias encountered when using internal tags, however further research is needed to confirm this.

A comparison of single-suture and double-suture incision closures in seaward-migrating juvenile Chinook salmon implanted with acoustic transmitters: implications for research in river basins containing hydropower structures

BackgroundReductions in the size of acoustic transmitters implanted in migrating juvenile salmonids have resulted in the ability to make smaller incisions that may warrant using only a single suture for closure. However, it is not known if one suture will sufficiently hold the incision closed, particularly when outward pressure is placed on the surgical site, such as when migrating fish experience pressure changes associated with passage at hydroelectric dams. The objective of this research was to evaluate the effectiveness of single-suture incision closures on juvenile Chinook salmon (Oncorhynchus tshawytscha).ResultsJuvenile Chinook salmon were surgically implanted with a 2012 Juvenile Salmon Acoustic Telemetry System (JSATS) transmitter (0.30 g) and a passive integrated transponder tag (0.10 g), and incisions were closed with either one suture or two sutures. Mortality and tag retention were monitored, and tagged fish were examined after 7 and 14 d to evaluate tissue responses. In a separate experiment, surgically implanted fish were exposed to simulated turbine passage and then examined for expulsion of transmitters, expulsion of viscera through the incision and mortal injury. With incisions closed using a single suture, there was no mortality or tag loss and similar or reduced tissue reaction compared to incisions closed with two sutures. Furthermore, surgery time was significantly reduced when a single suture was used, which led to less handling time and time under anesthesia and consequently, stress. No tags were expelled during pressure scenarios. Expulsion of viscera occurred in two non–mortally injured fish (5%) with single sutures that were exposed to very high pressure changes, but no viscera expulsion was present in fish exposed to pressure scenarios, likely representative of hydroturbine passage at many Columbia River dams (for example, <2.7 ratio of pressure change, acclimation pressure of 146.2 absolute kPa and lowest exposure pressure of about 53.3 absolute kPa).ConclusionsWe recommend the use of a single suture for surgical implantation of transmitters with incisions that are approximately 5.5 mm long after tag insertion.

Juvenile salmonid migratory behavior at the mouth of the Columbia River and within the plume

Early ocean experience is a critical time period that affects juvenile salmonid survival. Understanding juvenile salmonid behavior in nearshore marine environments and how oceanic conditions (such as dynamic river plume habitats) affect salmonid migration will contribute to salmonid survival studies and conservation and management efforts. Relatively few studies have been conducted on juvenile salmonid behavior as they migrate out the mouth of the Columbia River and some studies suggest that juvenile salmonids typically migrate north immediately upon entry into the ocean from the Columbia River. We present findings from a study that used acoustic telemetry to determine the migratory direction, residence time, and travel rate of juvenile salmonids as they left the Columbia River and entered the marine environment. A total of 8,159 acoustic-tagged salmonid smolts were detected at the mouth of the Columbia River. Of the fish detected at the mouth, an estimated 16% of yearling Chinook salmon, 10% of steelhead, and 26% of subyearling Chinook salmon were detected on a sparse array deployed outside the mouth of the Columbia River in the vicinity of the plume. The travel rate of Chinook salmon smolts decreased as they left the river and entered the marine environment, whereas the travel rate of steelhead increased. Chinook salmon also spent more time in the transitional area between the river mouth and plume compared to steelhead. In early spring, yearling Chinook salmon and steelhead were predominately detected on the plume array towards the edge of the shelf and to the south. Later in the season, yearling Chinook salmon and steelhead smolts were more often detected north of the river mouth. Subyearling Chinook salmon were most often detected on the portion of the plume array to the north of the river mouth. Our study showed that salmonid smolt migration out of the river into the nearshore marine environment appears to vary across species, season, and age class, and may be influenced by local environmental conditions. Direction of movement upon ocean entry cannot be assumed and is likely influenced by oceanic conditions such as wind and currents. We also present, for the first time, the utility of the Juvenile Salmon Acoustic Telemetry System (JSATS) to monitor the behavior of juvenile fish in the marine environment. Our results will help inform future studies using telemetry and hydroacoustics as well as trawl surveys to assess nearshore ocean juvenile salmonid distribution, behavior, and survival.

The Effects of Neutrally Buoyant, Externally Attached Transmitters on Swimming Performance and Predator Avoidance of Juvenile Chinook Salmon

AbstractMigrating juvenile salmonids experience rapid decompression that could result in injury or mortality due to barotrauma as they pass turbines at hydropower facilities. Recent research indicates that the risk of injury or mortality due to barotrauma is higher in fish bearing surgically implanted transmitters. Since tagged fish are used to represent the entire population, this tag effect potentially leads to inaccuracies in survival estimates for fish passing turbines. This problem led to development of a novel transmitter, the use of which may eliminate bias associated with the passage of transmitter‐bearing fish through turbines. Juvenile Chinook salmon Oncorhynchus tshawytscha were tagged with two different neutrally buoyant, externally attached transmitters (types A and B). The effects of transmitter presence on swimming performance were examined by comparing critical swimming speeds (Ucrit; an index of prolonged swimming performance) of externally tagged fish, untagged individuals, and fish that received surgically implanted Juvenile Salmon Acoustic Telemetry System acoustic transmitters. Fish tagged with external transmitters had lower Ucrit than untagged individuals. However, there was no difference in Ucrit between fish with external transmitter type A or B and fish with surgically implanted transmitters. Testing was conducted to determine whether predator avoidance was affected by the presence of type A transmitters compared with untagged fish. No difference in predation mortality was detected between tagged and untagged fish. Although results suggest that Ucrit was affected by externally attached transmitters in comparison with untagged fish, the overall impact as reflected by survival was similar; field‐based survival studies involving juvenile salmonids passing through hydroturbines are recommended. The absence of swimming performance effects in fish with external tags relative to fish with internally implanted transmitters and the lack of an increased predation risk relative to untagged fish suggest that an externally attached, neutrally buoyant transmitter is a viable option for telemetry studies in estimating survival of juvenile salmonids passing through hydroturbines.

Influence of Incision Location on Transmitter Loss, Healing, Survival, Growth, and Suture Retention of Juvenile Chinook Salmon

AbstractFisheries research involving surgical implantation of transmitters necessitates the use of methods that minimize transmitter loss and fish mortality and optimize healing of the incision. We evaluated the effects of three incision locations on transmitter loss, healing, survival, growth, and suture retention in juvenile Chinook salmon Oncorhynchus tshawytscha. The three incision locations were (1) on the linea alba (LA incision), (2) adjacent and parallel to the LA (muscle‐cutting [MC] incision), and (3) extending from the LA towards the dorsum at a 45° angle, between the parallel lines of myomeres (muscle‐sparing [MS] incision). A Juvenile Salmon Acoustic Telemetry System acoustic transmitter (0.44 g in air) and a passive integrated transponder tag (0.10 g in air) were implanted into each fish (total N = 936 fish). The fish were held at 12°C or 20°C and were examined weekly for 98 d. The progression of healing among incision locations and the variability in transmitter loss made it difficult to identify one incision location as the best choice. The LA incisions had a much smaller wound extent (area of visible subepidermal tissue) than MC and MS incisions during the first 28 d of the study. In both temperature treatments, apposition of incisions through day 14 was better for LA incisions than for MC and MS incisions. However, MC and MS incisions were less likely than LA incisions to reopen over time and thus were less likely to allow transmitter loss through the incision.

Development of external and neutrally buoyant acoustic transmitters for juvenile salmon turbine passage evaluation

Fish can sustain injury or mortality when they pass through hydroelectric facilities. To develop a method to monitor the passage and survival of juvenile salmonids without bias through turbines within the Federal Columbia River Power System, we developed and fabricated two designs of neutrally buoyant transmitters: Type A (sutured to the dorsal musculature of the fish anterior to the dorsal fin) and Type B (two-part design attached with wire pushed through the dorsal musculature, ventral to the dorsal fin). To determine the efficacy of the two designs under non-turbine passage-related conditions, fish had one of the tags attached and were held for 14 days to determine any potential effects of the tags on growth, survival and tissue damage. We also evaluated the attachment method by monitoring tag retention. These two neutrally buoyant tag designs were compared to nontagged individuals and those surgically implanted with current Juvenile Salmon Acoustic Telemetry System (JSATS) transmitters and passive integrated responder (PIT) tags. In addition, two suture materials (Monocryl and Vicryl Rapide) were tested for attachment of Type A tags. When compared with non-tagged individuals, fish tagged with Type A tags did not differ significantly with respect to growth or mortality over a 14-d holding period. However, fish tagged with Type B transmitters had lower growth rates than the nontagged controls or other tag treatments. The efficacy of two designs was also compared to nontagged individuals under shear exposure. Fish were exposed to a submerged, 6.35-cm-diameter water jet at velocities ranging from 3.0 to 12.2 m/s in a water flume to simulate turbine conditions within the Columbia River basin. Throughout the shear exposure study, no mortalities or tag loss were observed. There was also no significant difference in the rates of shear injury between untagged fish and fish tagged with Type A or Type B tags. When tissue damage was assessed for tagged individuals exposed to shear forces, those tagged with Type A tags showed lower rates and severity of injury when compared to Type B-tagged fish. Overall, Type A tags may be a viable tag design for juvenile Chinook salmon passing through hydropower facilities.

Hybrid CF x–Ag 2V 4O 11 as a high-energy, power density cathode for application in an underwater acoustic microtransmitter

This study demonstrates the excellent electrochemical performance of the hybrid carbon fluoride (CF x)/silver vanadium oxide (SVO)/graphene(G) cathode and its potential utilization in the Juvenile Salmon Acoustic Telemetry System (JSATS). The impedance increase caused by LiF formation is effectively addressed by silver metal deposition during SVO reduction. The coexistence of graphene additive reduces the initial voltage delay; thus, a prolonged operation voltage is observed with enhanced electronic conductivity, with specific capacity of ~ 462 mAhg −1 at 5C rate and 661 mAhg −1 at 1C rate. The peak current delivered from the as-designed hybrid cathode is improved over the commercial Zn/Ag 2O batteries, suggesting battery size/weight reduction critical for the JSATS transmitters.

A Cabled Acoustic Telemetry System for Detecting and Tracking Juvenile Salmon: Part 2. Three-Dimensional Tracking and Passage Outcomes

In Part 1 of this paper, we presented the engineering design and instrumentation of the Juvenile Salmon Acoustic Telemetry System (JSATS) cabled system, a nonproprietary sensing technology developed by the U.S. Army Corps of Engineers, Portland District (Oregon, USA) to meet the needs for monitoring the survival of juvenile salmonids through the hydroelectric facilities within the Federal Columbia River Power System. Here in Part 2, we describe how the JSATS cabled system was employed as a reference sensor network for detecting and tracking juvenile salmon. Time-of-arrival data for valid detections on four hydrophones were used to solve for the three-dimensional (3D) position of fish surgically implanted with JSATS acoustic transmitters. Validation tests demonstrated high accuracy of 3D tracking up to 100 m upstream from the John Day Dam spillway. The along-dam component, used for assigning the route of fish passage, had the highest accuracy; the median errors ranged from 0.02 to 0.22 m, and root mean square errors ranged from 0.07 to 0.56 m at distances up to 100 m. For the 2008 case study at John Day Dam, the range for 3D tracking was more than 100 m upstream of the dam face where hydrophones were deployed, and detection and tracking probabilities of fish tagged with JSATS acoustic transmitters were higher than 98%. JSATS cabled systems have been successfully deployed on several major dams to acquire information for salmon protection and for development of more “fish-friendly” hydroelectric facilities.