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Background Recent improvements in fixed acoustic monitoring receivers allow the tracking of individual aquatic animals over long periods of time with regular fine-scale positions. The VEMCO Positioning System (VPS) is now widely used, but various methodological issues remain to be clarified. The aim of this study was to analyze the spatial distribution of the probability of location and the positioning error over the entire surface of a hydropower reservoir, prior to analyzing fish behavior. Findings: Filtering the data set by the horizontal position error (HPE) significantly reduced the positioning error. Retaining only the positions with an HPE less than 15 retained 79% of VPS positions and decreased the positioning error by 33% (mean = 3.3 m, SD = 3.3 m). A higher probability of location was observed inside than outside the receiver array (44% and 36%, respectively). Moreover, the positioning error significantly differed inside (n = 243, mean = 2.4 m, SD = 2.1 m) and outside (n = 253, mean = 4.2 m, SD = 4.0 m) the receiver array (P < 0.001). Finally, the lowest positioning errors were detected in the area with the highest receiver density. Conclusions The VPS measures fish positioning in a reservoir, under suitable conditions, with satisfactory accuracy. We showed that the probability of location and the positioning error differed spatially in accordance with previous results in other conditions. Consequently, these analyses are recommended as a prerequisite to further spatial analyses using VPS-derived data.
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... Many studies have utilized the Fine Scale Positioning System (FSPS) from Innovasea Systems, Inc. (Nova Scotia, Canada), formerly Vemco Positioning System (VPS). The FSPS uses the time difference of arrival (TDOA, 57) derived from acoustic transmissions at multiple (i.e., three or more) receivers to accurately position tagged animals in space and time [12,42]. As such, these systems can be used to ask previously unreachable questions regarding fine-scale behavior and species interactions that cannot be ascertained using other biotelemetry techniques [8,25,36,51]. ...
... HPE is a unitless metric that may be influenced by the effects of the geometry of transmitter positions and detecting receivers and is commonly utilized when fixed transmitter/receiver locations are unknown [57], [ 58]. While HPE values are array-dependent, previous work has suggested filtering positions with HPE < 15 can provide a 33% decrease in positioning error [42]. RMSE refers to a time-based positioning error due to multipath signals, such as signal reflection or refraction [57]. ...
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Rapid global expansion of offshore wind farms, tidal, and wave technologies signifies a new era of renewable energy development. While a promising means to combat the impacts of climate change, such developments necessitate fine-scale monitoring of biological communities to determine impacts associated with construction, operation, and eventual decommission. Here, we evaluate the performance of a gridded, Innovasea Systems, Inc. fine-scale acoustic telemetry positioning system (FSPS, n = 20 acoustic receivers) for tracking behaviors of diverse, temperate fish assemblages in relation to a subsea cable route supporting the Ørsted offshore wind development in coastal New York. We examined array performance through positioning error derived from receiver reference transmitters and tracked animals (n = 260) comprising 17 species of teleost and elasmobranch. We evaluated the effects of environmental variables (temperature, tilt, noise, and depth), transmitter power, individual movement rates, and receiver loss on horizontal positioning error (HPE) and route mean squared error (RMSE). Across a 16-month deployment period, many positions were derived for Atlantic sturgeon (n = 2,612), black sea bass (n = 9,175), clearnose skate (n = 10,306), summer flounder (n = 13,304), and little skate (n = 15,186), suggesting that these species may serve as sentinel candidates for assessing behavioral changes following construction, operation, and decommission. We found that receivers placed at the boundary of the grid exhibited higher HPE and RMSE, however these errors did not significantly change despite large receiver losses (25%). Generalized Linear Models revealed that temperature, noise, tilt, and depth were often significant predictors of HPE and RMSE, however, a substantial amount of variance was not explained by the models (~ 70%). Average movement rates ranged from 1.1 m s⁻¹ (common thresher shark) to 0.03 m s⁻¹ (little skate and summer flounder) but had minimal effects on positioning error. Finally, we observed that higher transmitter powers (158 dB) may lead to higher and more variable HPE values. Overall, these findings provide new insight into the drivers of FSPS array performance and illustrate their broad utility for monitoring fish behavior associated with offshore marine developments.
... Few data were available on fish movement in this area, yet it is not known whether this is due to a decision by the fish or constraints of the data. This region was beyond the extent of the 2D acoustic telemetry array, meaning fish positions in this area would have a high associated positioning error (Roy et al., 2014). As a result, while few calibrating data were available in this region, we cannot know whether fish use it or not. ...
... HPE can then be related to measured horizontal position error in meters (HPEm) for stationary synchronization and reference tags, for which the "true" positions are known (Smith, 2013), to attempt to relate HPE to potential horizontal errors and identify thresholds for filtering (Roy et al., 2014). This point-by-point approach for filtering VPS positions is commonly used, but particularly in reflective environments a track-oriented approach such as YAPS may perform better (Vergeynst et al., 2020). ...
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Identifying and characterizing spawning locations are paramount for the protection of critical fish habitats but can be challenging, particularly in remote locations. Using the underexplored oviduct‐tagging technique, we aimed to identify the timing and location of spawning for wild Arctic char (Salvelinus alpinus) and lake trout (Salvelinus namaycush) in two high‐Arctic lakes in Nunavut. Specifically, Innovasea V7 acoustic telemetry transmitters were inserted into the oviducts of 13 Arctic char and 4 lake trout, and the timing and location of tag expulsion were determined using a fine‐scale positioning system. Twenty Arctic char and 20 lake trout were also tagged with abdominal V16 transmitters, and 10 of them were paired with the oviduct tags, to further study the behavior of individual fish during the spawning season. Oviduct tags from four Arctic char and one lake trout could be used to assess the timing and location of spawning. Spawning anadromous Arctic char drastically reduced their activity and remained proximate to their presumed spawning location immediately before and for months after spawning. In contrast, a non‐anadromous (i.e., freshwater resident) Arctic char and a lake trout showed little to no reduction in activity around presumed spawning events. Because of the highlighted sedentary behavior of inferred spawning anadromous Arctic char implanted with both abdominal and oviduct tags, we could also infer potential spawning based on the behavior of individuals equipped only with abdominal tags. Spawning areas identified via telemetry also aligned well with Inuit knowledge of those lakes. This is the first field study to use acoustic oviduct and abdominal tags coupled with a fine‐scale positioning system. Despite a limited success rate of ejection, the study reveals the strong potential of the method to study spawning habitat and timing, particularly in remote areas.
... Prior analysis of the VPS determined an HPE value of 16 to be the optimal threshold for positional accuracy without reducing too much of the dataset via filtering (Golder Associates Ltd. 2015). This value lies within the typical 10 to 20 HPE threshold range of other VPS studies (Roy et al. 2014). ...
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The Chinese sturgeon (Acipenser sinensis) is a critically endangered, large migratory fish that serves as a vital indicator of ecological status of marine and river environments. Conservation efforts for Chinese sturgeon primarily focus on freshwater rearing, potentially leading to smaller adult sizes and higher disease incidence due to limited exposure to marine environments. Thus, it is imperative to study the behavioural characteristics and marine life history of artificially reared populations in seawater environments. In this study, acoustic telemetry technology was employed to investigate the behaviour of the Chinese sturgeon. We deployed an acoustic array at a nearshore-fenced marine farm on Bailong Island and conducted a one-year (December 2020–December 2021) tracking of ten acoustic-tagged fish, comprising five adults and five juveniles. We generated distribution heat maps and analysed displacement during typhoons and tidal events to differentiate activity levels. Annual distribution revealed areas of distinct increased density, with adults displaying a denser distribution compared to the more scattered pattern observed in juveniles. Rhythmic behaviour in response to tidal cycles was observed. During typhoon periods, individuals exhibited reduced activity levels but increased concentration, with no significant diurnal behavioral variations. These age-specific and environmentally responsive habitat preferences provide valuable supplementary insights into the species' life history and potential conservation strategies. Graphical Abstract
... The profile of HPE is specific to each acoustic network set-up, i.e. not comparable to other studies. Similar to [17,31,32], the HPE associated with each cod position was used to filter out deviates. Here, the highest 2% HPE quantile was filtered out. ...
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Globally, biogenic temperate reefs are among the most threatened habitats. In the North Sea in particular, large shellfish reefs were lost owing to fishing activities in the 1900s. The impact of offshore wind farms (OWFs) on marine wildlife is extensive, and it offers the possibility to reintroduce new hard substrate habitats that are protected from fisheries at a large scale. In addition to the submerged structures of OWFs, marine hard substrate habitat can be further enhanced by providing extra artificial reefs. In an operational OWF along the Dutch coast, four artificial reefs (two with a scour bed and two without) were deployed in the vicinity of a wind turbine. Acoustic telemetry was used to monitor the fine-scale movement of 64 Atlantic cod (Gadus morhua). The monitoring ran from July 2021 to January 2023. Detailed information on behaviour, area utilization and attraction to the structures was determined. Results showed strong attraction (high site fidelity and residency) to the artificial reef, with no significant difference between the two tested types of reefs, and only a few individuals staying over winter. Cod spent a large proportion of their time hiding in the artificial reefs, suggesting that adding pipes for shelter has a beneficiary effect.
... In a VPS, receivers need to be placed at a distance from one another that allows for at least three receivers to detect the ping emitted by a tag, allowing for the position of the fish to be triangulated and tracked over time (Smith, 2013). Tag positions are calculated from raw detections using hyperbolic positioning algorithms which are based on the time-distance-of arrival of transmissions among receivers at fixed locations with synchronized clocks (Smith, 2013;Meckley et al., 2014;Roy et al., 2014). ...
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... The low proportion of positions in the 0-2 m lake depth layer could be an artifact of the VPS array's performance (e.g. lower probability of detection nearshore; Roy et al. 2014), water level fluctuation or ice thickness during winter and should thus be interpreted with caution. For instance, natural water level fluctuation was around 20 cm in Lake Ledoux and ice thickness could reach 70 cm at the end of the winter season in nearby lakes (Pépino unpubl.), ...
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... In this study, we investigated space use in the context of no-take zones by re-analysing tracking data previously collected and published in . Data were collected using high-resolution acoustic tags in a hyperbolic positioning system (Roy et al., 2014) at the Taylors Beach no-take zone ( Figure 1). Eighteen large, adult crabs (>100 mm CL) were tagged during the late austral summer (February 2020) and tracked for up to 196 d, the estimated maximum battery life of tags . ...
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