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Site fidelity and movement patterns of reef manta rays  (Mobula alfredi): Mobulidae using passive acoustic telemetry in northern Raja Ampat, Indonesia

Site fidelity and movement patterns of reef manta rays (Mobula alfredi): Mobulidae using passive acoustic telemetry in northern Raja Ampat, Indonesia

Though extremely valuable to the local marine tourism industry, there is a dearth of published information on the ecology and population dynamics of reef manta rays (Mobula alfredi) in Raja Ampat, West Papua, In- donesia. Knowledge of the movement ecology in particular of this large and scattered population is urgently needed to better manage the rapidly expanding manta-focused tourism. Here we report the results of an initial passive acoustic telemetry study designed to provide local managers with the first detailed knowledge of the site use and movement patterns of reef mantas in northern Raja Ampat. A total of 39 reef mantas were tagged with Vemco V16 acoustic transmitters over a 15-month period between 27 November 2013 and 22 February 2015. To monitor their movements, VR2W acoustic receivers were deployed at eight sites corresponding to known manta cleaning and feeding aggregation sites, with receivers downloaded every six months over a two-year initial monitoring period. The duration between tag deployments and last date of detections at sites ranged from 1 to 682 days (mean ± SE = 237 ± 27). The cumulative number of days of manta detections at receiver sites by individual mantas ranged from 1 to 188 days (mean ± SE = 42 ± 7). Manta Ridge was the most visited site with 565 days of detections. The tagged mantas demonstrated strong site fidelity to the ob- served aggregation sites. At the same time, they also exhibited seasonal movements within an approximately 150 km long corridor between sites in the Dampier Strait and the northwest of Waigeo Island. Data analysed from a nearby array of six VR2W receivers in southern Raja Ampat (approximately 180 km to the south of the study area) confirmed that none of the tagged mantas were detected in this array, providing further evidence of strong site fidelity and limited movements within northern Raja Ampat. More than 96% of detections occurred during the daytime. The number of detections reached a peak around noon at Yefnabi Kecil and Eagle Rock and slightly earlier at Manta Ridge. These findings have been shared with the Raja Ampat Marine Protected Area Management Authority and are now being used in the formulation of a management plan for this vulner- able and economically important species to ensure the long-term health of Raja Ampat’s reef mantas and the sustainability of manta tourism in the region.
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Potential detection of illegal fishing by passive acoustic telemetry

Potential detection of illegal fishing by passive acoustic telemetry

Acoustic tagging is typically used to gather data on the spatial ecology of diverse marine taxa, informing questions about spatio-temporal attributes such as residency and home range, but detection data may also reveal unan- ticipated insights. Many species demonstrate predictable site fidelity, and so a sudden cessation of detections for multiple individuals may be evidence of an atypical event. During 2013 and 2014, we acoustically tagged 47 grey reef sharks (Carcharhinus amblyrhynchos) and 48 silvertip sharks (Carcharhinus albimarginatus) near reefs in the Brit- ish Indian Ocean Territory (BIOT) Marine Protected Area (MPA). From March 2013 to November 2014 inclusive, tags were ‘lost’, i.e. permanently ceased to be detected within the monitoring area, at an average rate of 2.6 ± 1.0 tags per month. Between 1 and 10 December 2014, detection data suggest the near-simultaneous loss of 15 of the remaining 43 active tagged sharks, a monthly loss rate over five times higher than during the previous 21 months. Between 4 and 14 December of 2014, the BIOT patrol vessel encountered 17 vessels engaged in suspected illegal fishing in the northern BIOT MPA; such sightings averaged one per month during the previous 8 months. Two of these vessels were arrested with a total of 359 sharks on board, of which grey reef and silvertip sharks constituted 47% by number. The unusual and coincident peaks in tag loss and vessel sightings, and the catch composition of the arrested vessels, sug- gest illegal fishing as a plausible explanation for the unusual pattern in our detection data. A Cox proportional hazards model found that the presence of fishing vessels increased the risk of tag loss by a factor of 6.0 (95% CI 2.6–14.0, p < 0.001). Based on the number of vessels sighted and the average number of sharks on vessels arrested in BIOT during 2014, we conservatively estimate that over 2000 sharks may have been removed during the suspected fishing event. Based on average catch compositions, over 1000 would have been grey reef and silvertip sharks. Assuming a closed population mark-recapture model, over one-third of the locally resident reef sharks may have been removed from the monitoring area. The data suggest that even sporadic fishing events may have a marked impact on local reef shark populations, but also demonstrate the potential of electronic tagging a tool for detecting illegal or otherwise unreported fishing activity.
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Habitat and dietary selectivity of nearshore shark populations

Habitat and dietary selectivity of nearshore shark populations

158 159 Passive acoustic telemetry was used to examine the residency, space use, and habitat 160 selection and specialisation patterns of the small-bodied Australian sharpnose shark, 161[r]

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A standardised framework for analysing animal detections from automated tracking arrays

A standardised framework for analysing animal detections from automated tracking arrays

The VTrack package, developed and used in the R sta- tistical environment [25], provides a suite of analysis tools to calculate animal movement metrics using passive acoustic telemetry data [26]. VTrack was initially devel- oped for linear systems (e.g. rivers) and did not provide standardised metrics of activity space of tagged animals. The original package was also not built to integrate data held within large-scale telemetry data repositories with multiple data contributors. We have extended the VTrack package to include the Animal Tracking Toolbox (ATT), a tool-set that includes a collection of new functions to estimate metrics of detection, dispersal, short-term centres of activity and home range from passive telem- etry datasets. The methods used to calculate home range areas using node-based datasets are constantly evolving, with a multitude of techniques being used and developed to provide more accurate estimates of activity space. The ATT provides a repeatable technique to calculate esti- mates of activity space using three commonly used meth- ods: the minimum convex polygon (MCP), fixed kernel utilisation distribution (KUD), and kernel utilisation dis- tributions estimated using Brownian Bridge movement models (often referred to as UD, henceforth referred to as BB-KUD here).
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A new seafloor electromagnetic station with an Overhauser magnetometer, a magnetotelluric variograph and an acoustic telemetry modem

A new seafloor electromagnetic station with an Overhauser magnetometer, a magnetotelluric variograph and an acoustic telemetry modem

Key (PSK) ATM is desirable instead of MFSK ATM though it is still feasible to handle the 1-year dataset in 10 hrs by the presently fastest 1200 baud transmission. Stable acoustic communication at much longer distances is also preferable since the error rate of the present ATM is proved to abruptly rise up at distances longer than two nautical miles. Orien- tation of the SFEMS at the seafloor can now only be deter- mined with respect to the geomagnetic north, which can be calculated from the 3-component magnetic data by the MT variograph. Addition of a gyrocompass is another necessary future improvement since knowledge of the geographical ori- entation is crucial to distinguish the true geomagnetic secular variation from the drift of the magnetic sensors.
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Response of Atlantic salmon Salmo salar to temperature and dissolved oxygen extremes established using animal borne environmental sensors

Response of Atlantic salmon Salmo salar to temperature and dissolved oxygen extremes established using animal borne environmental sensors

two cages owned by Huon Aquaculture, approximately 600 m apart, located in the central harbour (Fig. 5). Total depth at the two sites was between 40 and 45 m, cage depth was approximately 17 m, cage circumference was 160 m. Both cages were stocked with triploid Atlantic salmon hatched at Huon’s Millybrook Hatchery and moved into the sea cages in Macquarie Harbour in July/August the previous year (2014) and scheduled for harvest at the end of the study period (March 2016). Total number of fish in cage 1 was 36512 with an average weight at time of tagging of 3625 g, total number of fish in cage 2 was 34270 with an average weight at time of tagging of 4175 g. Tag deployment. To determine the behavioral response of salmon to changes in environmental condi- tions we deployed VEMCO acoustic telemetered sensors (17.5 × 106.5 mm; 19.78 g weight in seawater; ~160 db power output, 69 kHz frequency; VEMCO, Nova Scotia, Canada), which measure pressure (0–102 m), temper- ature (0–25 °C) and dissolved oxygen (0–140%) approximately simultaneously (within 250 milliseconds of one another) and transmit the resulting data together with the tags’ ID coded as a series of acoustic pings (one ping series per environmental variable) which were recorded together with the date and time of transmission by an acoustic receiver deployed at the center, bottom of the cages, pointing up. To reduce the probability of signals from different tags colliding, transmission intervals were randomized within a set range. The DO sensor inte- grated in the tag was the optical RedEye oxygen sensor patch (Ocean Optics,, Dunedin, FL, USA) which has an accuracy range of 0.01 to 0.1% and a response time of less than 20 seconds. Since the tags did not measure salinity, DO was transmitted as % saturation rather than mg/L.
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Passive Acoustic Emissions Monitoring of Fluidized Bed Pellet Coating

Passive Acoustic Emissions Monitoring of Fluidized Bed Pellet Coating

Additional work is required to translate the technique from a potential monitoring method to implementation in pharmaceutical manufacturing processes. FDA regulatory approval has made the introduction of new technologies into the pharmaceutical industry slow and difficult. For industrial application improvements to the method’s robustness and ability to reliably monitor and control the coating process is required. Continued research is necessary to further confirm the ability of passive acoustic emissions monitoring to minimize human and process error, improve product quality and process efficiency, and reduce waste or the number of discarded batches. This is needed to obtain regulatory approval and would be the main focus of continued work. This may include focusing on different frequency ranges within the signal to relate the emissions profile to different aspects of the process. Currently we have shown the acquired emissions reflect process changes but additional analysis is necessary to further relate specific aspects of the signal to the coating process in the interest of process monitoring and control.
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Behavioral attributes of turbine entrainment risk for adult resident fish revealed by acoustic telemetry and state-space modeling

Behavioral attributes of turbine entrainment risk for adult resident fish revealed by acoustic telemetry and state-space modeling

Figure 1 Study site and acoustic telemetry array. (a) Kinbasket Reservoir with inset showing the province of British Columbia, Canada. The arrow in the inset shows the location of the reservoir. (b) Forebay of Mica Dam showing the locations (surveyed once) of the acoustic telemetry receivers (black circles). The white crosses identify the fixed-position receivers with a beacon tag used to assess the performance of the telemetry positioning system. The black cross within the array denotes the location of the beacon tags whose detections were used to adjust the receivers ’ clock drift. The black rectangle and polygon denote, respectively, the top of the powerhouse and part of the dam. The rectangle adjacent to the top of the powerhouse denotes the powerhouse wall. The small white rectangles on the wall denote the intakes, which are numbered 1 to 6 from right to left (only intakes 1 to 4 are operational). The dashed contour lines denote the water depth (in meters) below the surface at high pool. The reservoir is located at Universal Transverse Mercator (UTM) Zone 11.
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Movements and foraging of predators associated with mesophotic coral reefs and their potential for linking ecological habitats

Movements and foraging of predators associated with mesophotic coral reefs and their potential for linking ecological habitats

tion to the isotopic composition of the primary pro- ducers at the base of the food chain from which the predator feeds (e.g. Post 2002). However, the spatial resolution of isotope analysis is such that feeding locations can generally only be resolved over large spatial scales and are unsuitable for studies at the diel scale (Carlisle et al. 2012). A recent study of the shallow reefs of the remote Northwestern Hawaiian Islands (NWHI) suggested that the major carbon source for shallow reef food webs came from benthic algae (Hilting et al. 2013). However, there are gener- ally higher abundances of planktivorous fishes on MCEs, with lower numbers of herbivores, particu- larly in Hawaii (Slattery et al. 2011, Kahng et al. 2014, Kane et al. 2014). This suggests that phyto- plankton is a more important carbon source on Hawaiian MCEs and that it is possible to resolve predator foraging on shallow versus MCE habitats. The goal of our study was to use acoustic telemetry to quantify horizontal and vertical movements of mar- ine predators (sharks and teleosts) at an MCE sur- rounding an uninhabited Hawaiian atoll. We then used the carbon and nitrogen isotopic compositions of these predators to infer foraging habitats and eval- uate the direction of nutrient transfer.
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Theoretical Analysis of a Passive Acoustic Brain Monitoring System

Theoretical Analysis of a Passive Acoustic Brain Monitoring System

In human physiology, arterial conducted heart pulses are coupled to the brain so that the brain pulses in phase with the heart when the time lag for signal propagation is taken into account. However, when the brain functionality is disturbed by injury, disease or is excited by external stimuli, its consistency changes in such way that the signal which is sensed at the skull using a sensitive detecting device does no longer coincides with the arterial pulse wave. This signal arises from functional activation of respective brain regions (volumes) or from phenomena such as lack of perfusion in the brain, edema causing decreased compliance and consequent loss of perfusion, and infarcts which alter the consistency of the brain tissue and hence its acoustic properties. This latter effect characterizes the occurrence of brain tumors as well. Apart from the aforementioned, signal anomalies can also be seen in intra-operative loss of perfusion in the brain where circulation can be impaired for periods of time during procedures such as open-heart surgery. The same principles apply when measuring alterations of flow patterns in the circulatory system arising from impediments to flow, such as clots that may occur downstream from the heart, and can be detected at an artery beyond the clot [3].
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Fine-scale movements of the broadnose sevengill shark
and its main prey, the gummy shark

Fine-scale movements of the broadnose sevengill shark and its main prey, the gummy shark

However, despite only covering a small spatial scale, radio- acoustic positioning systems provide the triangulated position of tracked animals, which can elucidate fine-scale behaviours, compared to the presence/absence data provided over larger spatial scales by passive receivers [60]. Regardless, for large mobile predators such as sharks, this system will be more useful for species that have a focal point, i.e. a discreet area of intense activity to centre the study around. For example, white sharks congregating seasonally around seal colonies to hunt [10]. However, despite the inherent difficulties of obtaining fine-scale movement behaviour of large predators, empirical data is needed to complement other data sources such as dietary information and prey abundance, and to supplement predator-prey modelling studies [61].
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Passive acoustic measurement of flow velocity in the Straits of Florida

Passive acoustic measurement of flow velocity in the Straits of Florida

measurements of the acoustic travel time nonreciprocity and to give robust estimates of the depth-averaged flow velocity, despite very limited a priori information about the noise sources and sound propagation conditions. Further research is necessary to improve accuracy and extend the measurements to longer ranges. Anticipated future development of inexpensive low-power atomic clocks should lead to improved accuracy while simplify- ing the analysis. It is expected that wider frequency bands of ambient noise will prove useful for passive measurements on refracted acoustic paths and in less dynamic environments representative of the deep ocean. Flow velocity measurements complement previously demonstrated [14] passive measurements of the sound speed profile (and, therefore, water temperature) and open the possibility of using acoustic noise interferometry to measure heat fluxes in the ocean.
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Extent of predation bias present in migration survival and timing of Atlantic salmon smolt (Salmo salar) as suggested by a novel acoustic tag

Extent of predation bias present in migration survival and timing of Atlantic salmon smolt (Salmo salar) as suggested by a novel acoustic tag

Recent technological innovations have allowed for the production of a novel acoustic tag type, referred to as a predator tag, that directly detects the occurrence of a predation event. This tag signals consumption events based on a change in identification code triggered by the change in pH associated with the predator’s gastrointes- tinal tract [8]. Although there is still a time lag associ- ated with detection of a predation event (due to the time necessary for digestion, signal switching, and subsequent detection), these tags possess the potential to segregate pre- and post-predation detections within the temporal and spatial extent of the study; an advantage not held by any known behaviour-based model. Thus, predator tags permit the removal of some degree of predation bias from migration metrics. Furthermore, if the goal is to identify the predation rate of the target species without the need to identify the predatory species, then there is no requirement for knowledge of the behaviours, and
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Using Acoustic Telemetry and Population Genetics to Investigate Cobia Stock Structure in the Southeast U.S.

Using Acoustic Telemetry and Population Genetics to Investigate Cobia Stock Structure in the Southeast U.S.

We surgically implanted acoustic transmitters in cobia to track cobia migratory behavior. Tagging occurred along coastal estuaries and nearshore regions of NC and VA, USA during spring and summer 2018 and 2019. We caught cobia using natural bait (live or dead on 9/0 circle or j hook) or artificial jigs often in cooperation with local charter boat captains. We used a landing net to subdue cobia and keep them submerged while surgery materials were prepared. For each cobia captured, we recorded fork length (FL, mm), capture location (GPS coordinates), fight time (from hooking to landing), surgery time (from removal from water to return to water), and release condition (Table 1); the release condition was based on that used by Heupel and Simpfendorfer (2002).
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An approach for filtering hyperbolically positioned underwater acoustic telemetry data with position precision estimates

An approach for filtering hyperbolically positioned underwater acoustic telemetry data with position precision estimates

PPE error estimates are frequently available from animal telemetry systems that rely on hyperbolic positioning and can be used to evaluate data quality prior to ana- lysis. When using PPE to filter data, practitioners should undertake (a) a priori determination of data accuracy re- quirements; (b) independent assessment of the telemetry system performance; (c) a determination of how well the PPE represents measured accuracy; (d) selection of a filter cutoff based on the balance between accuracy improve- ment and data retention; and (e) explicit consideration of spatial, behavioral, and habitat bias associated with the telemetry system and the animal under observation. A carefully constructed PPE filter is more defensible than biological filters that can improve data accuracy but re- quire (1) an interpretation of the data vs. an assessment of its precision, and (2) are only applied to a subset of the data collected (extreme movements). HPE offers the intri- guing possibility for direct use in the analysis as an error estimate (vs. a criterion for data retention); akin to bench apparatus precision estimates, though there is no evidence that this approach has been used in such a manner with other hyperbolic positioning systems. Because data ana- lysis requirements are likely to be as varied as the move- ment data to which they are applied, complete exposition of the selection process and criteria should be included in the methods section of any subsequent reports or publica- tions. The minimum level of a reporting should include a
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Residency and spatial use by reef sharks of an isolated seamount and its implications for conservation

Residency and spatial use by reef sharks of an isolated seamount and its implications for conservation

Although marine protected areas (MPAs) are a common conservation strategy, these areas are often designed with little prior knowledge of the spatial behaviour of the species they are designed to protect. Currently, the Coral Sea area and its seamounts (north-east Australia) are under review to determine if MPAs are warranted. The protection of sharks at these seamounts should be an integral component of conservation plans. Therefore, knowledge on the spatial ecology of sharks at the Coral Sea seamounts is essential for the appropriate implementation of management and conservation plans. Acoustic telemetry was used to determine residency, site fidelity and spatial use of three shark species at Osprey Reef: whitetip reef sharks Triaenodon obesus, grey reef sharks Carcharhinus amblyrhynchos and silvertip sharks Carcharhinus albimarginatus. Most individuals showed year round residency at Osprey Reef, although five of the 49 individuals tagged moved to the neighbouring Shark Reef (,14 km away) and one grey reef shark completed a round trip of ,250 km to the Great Barrier Reef. Additionally, individuals of white tip and grey reef sharks showed strong site fidelity to the areas they were tagged, and there was low spatial overlap between groups of sharks tagged at different locations. Spatial use at Osprey Reef by adult sharks is generally restricted to the north-west corner. The high residency and limited spatial use of Osprey Reef suggests that reef sharks would be highly vulnerable to targeted fishing pressure and that MPAs incorporating no-take of sharks would be effective in protecting reef shark populations at Osprey and Shark Reef.
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Development of an acoustic telemetry tag for monitoring electromyograms in free swimming fish

Development of an acoustic telemetry tag for monitoring electromyograms in free swimming fish

Although work in the open ocean should reduce multipath problems (due to the reduced number of reflective surfaces) we have several reasons for focusing initially on a system for the laboratory. The low-range requirements in the tanks reduced the tag size. The use of captive animals allowed us to verify that the signal corresponded to muscle contraction, simplifying initial development. In the tanks it is possible to maintain a direct connection to the tag for comparisons of the acoustic and electrical EMG waveform. Finally, initial efforts with captive fish, where activity can be monitored and temperature controlled, provide an important foundation for subsequent at-sea research. Our ultimate objective is to develop an inexpensive tag and receiving system for work both in the laboratory and at sea.
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The Use of Electronic Tags in Fish Research – An Overview of Fish Telemetry Methods

The Use of Electronic Tags in Fish Research – An Overview of Fish Telemetry Methods

Radio telemetry is a particularly useful method when studying fish behaviour and migrations in river systems, because tagged fish distributed over a large study area can be tracked for instance by driving a car or boat along the river, or flying over the river by an aircraft, with a portable receiver and aerial antenna. Tagged fish can also be recorded by stationary receivers/loggers. The method is widely used in studies to increase the general knowledge of river migrations of freshwater and diadromous fishes (e.g. Almeida et al., 2002; Hodder et al., 2007; Koehn et al., 2009). It is also widely used to identify migration barriers and evaluate mitigation measures in rivers regulated for hydropower purposes, or impacted by other anthropogenic installations or regulations (e.g. Thorstad et al., 2003; Calles et al., 2010). Catch-and- release angling is increasingly practised by anglers, which involves releasing the live fish back to the waters where they were captured, presumably to survive unharmed. Radio tagging and other telemetry methods have been used in a number of studies to assess mortality rates, behavioural impairments, or to evaluate the effects of displacement on fish after catch-and-release (reviewed by Donaldson et al., 2008).
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Making connections in aquatic ecosystems with acoustic telemetry monitoring

Making connections in aquatic ecosystems with acoustic telemetry monitoring

Figure 3) behavior and survival as they transition from freshwater rearing habitats to coastal Pacific Ocean waters (Welch et al. 2009), to movement behaviors of gray seals (Halichoerus grypus; Figure 4) in the northwest- ern Atlantic Ocean (Lidgard et al. 2012). Although much knowledge has already been gained, field-based acoustic monitoring applications have the potential to address emerging questions regarding animal behavior. For example, investigating behavioral anomalies, such as the presence of individuals outside their typical ranges, can provide information on migration behaviors and home ranges. Such findings may be particularly valuable in a climate-change context, given that the ranges of some species are expected to shift (Hampe and Petit 2005). Even a relatively small dataset can provide impor- tant insights, for example, into potential rarely observed offshore foraging behaviors of northern elephant seals ([Mirounga angustirostris]; Hayes et al. 2013), particularly when investigated with novel modeling techniques Figure 1. Key acoustic telemetry monitoring research topics for (a) basic and (b) applied science. A heat map illustrates the number of published acoustic monitoring papers associated with each research topic (blue representing the most papers, red representing the least papers) based on keyword search returns using Web of Science. The combination of keywords began as (“acoustic network” or “acoustic telemetry” or “acoustic biotelemetry” or “acoustic tracking” or “acoustic biotracking”) and was refined to “acoustic telemetry” or “acoustic tracking” and (network or array or monitoring). The resulting keywords were then further refined by each individual topic covered in the review to generate the numbers presented in the figure (eg for habitat quality indicators, the refined by topic included “habitat quality indicator” “habitat quality” or “habitat loss” or urbanization or degrad * or connectivity or
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A review of acoustic telemetry in Europe and the need for a regional aquatic telemetry network

A review of acoustic telemetry in Europe and the need for a regional aquatic telemetry network

Results: Over the past decade, there was an approximately sevenfold increase in the number of acoustic telemetry studies published on marine and diadromous species in Europe compared to a sixfold increase globally. Over 90% of these studies were conducted on fishes and undertaken in coastal areas, estuaries, or rivers. 75% of these stud- ies were conducted by researchers based in one of five nations (Norway, UK, France, Portugal, and Spain) and, even though 34% were based on collaborations between scientists from several countries, there was only one study with an acoustic receiver array that extended beyond the borders of a single country. In recent years, acoustic telemetry in European waters has evolved from studying behavioural aspects of animals (82.2%), into more holistic approaches addressing management-related issues (10%), tagging methods and effects (5%), and technology and data analysis development (2.8%).
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