The Experts below are selected from a list of 8271 Experts worldwide ranked by ideXlab platform
David Peel - One of the best experts on this subject based on the ideXlab platform.
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unmanned aerial vehicles for surveying Marine Fauna assessing detection probability
Ecological Applications, 2017Co-Authors: Amanda Hodgson, David Peel, Natalie KellyAbstract:Aerial surveys are conducted for various Fauna to assess abundance, distribution, and habitat use over large spatial scales. They are traditionally conducted using light aircraft with observers recording sightings in real time. Unmanned Aerial Vehicles (UAVs) offer an alternative with many potential advantages, including eliminating human risk. To be effective, this emerging platform needs to provide detection rates of animals comparable to traditional methods. UAVs can also acquire new types of information, and this new data requires a reevaluation of traditional analyses used in aerial surveys; including estimating the probability of detecting animals. We conducted 17 replicate UAV surveys of humpback whales (Megaptera novaeangliae) while simultaneously obtaining a ‘census’ of the population from land-based observations, to assess UAV detection probability. The ScanEagle UAV, carrying a digital SLR camera, continuously captured images (with 75% overlap) along transects covering the visual range of land-based observers. We also used ScanEagle to conduct focal follows of whale pods (n = 12, mean duration = 40 min), to assess a new method of estimating availability. A comparison of the whale detections from the UAV to the land-based census provided an estimated UAV detection probability of 0.33 (CV = 0.25; incorporating both availability and perception biases), which was not affected by environmental covariates (Beaufort sea state, glare, and cloud cover). According to our focal follows, the mean availability was 0.63 (CV = 0.37), with pods including mother/calf pairs having a higher availability (0.86, CV = 0.20) than those without (0.59, CV = 0.38). The follows also revealed (and provided a potential correction for) a downward bias in group size estimates from the UAV surveys, which resulted from asynchronous diving within whale pods, and a relatively short observation window of 9 s. We have shown that UAVs are an effective alternative to traditional methods, providing a detection probability that is within the range of previous studies for our target species. We also describe a method of assessing availability bias that represents spatial and temporal characteristics of a survey, from the same perspective as the survey platform, is benign, and provides additional data on animal behavior.
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Unmanned aerial vehicles (UAVs) for surveying Marine Fauna: A dugong case study
PLoS ONE, 2013Co-Authors: Amanda Hodgson, Natalie Kelly, David PeelAbstract:Aerial surveys of Marine mammals are routinely conducted to assess and monitor species' habitat use and population status. In Australia, dugongs (Dugong dugon) are regularly surveyed and long-term datasets have formed the basis for defining habitat of high conservation value and risk assessments of human impacts. Unmanned aerial vehicles (UAVs) may facilitate more accurate, human-risk free, and cheaper aerial surveys. We undertook the first Australian UAV survey trial in Shark Bay, western Australia. We conducted seven flights of the ScanEagle UAV, mounted with a digital SLR camera payload. During each flight, ten transects covering a 1.3 km(2) area frequently used by dugongs, were flown at 500, 750 and 1000 ft. Image (photograph) capture was controlled via the Ground Control Station and the capture rate was scheduled to achieve a prescribed 10% overlap between images along transect lines. Images were manually reviewed post hoc for animals and scored according to sun glitter, Beaufort Sea state and turbidity. We captured 6243 images, 627 containing dugongs. We also identified whales, dolphins, turtles and a range of other Fauna. Of all possible dugong sightings, 95% (CI = 90%, 98%) were subjectively classed as 'certain' (unmistakably dugongs). Neither our dugong sighting rate, nor our ability to identify dugongs with certainty, were affected by UAV altitude. Turbidity was the only environmental variable significantly affecting the dugong sighting rate. Our results suggest that UAV systems may not be limited by sea state conditions in the same manner as sightings from manned surveys. The overlap between images proved valuable for detecting animals that were masked by sun glitter in the corners of images, and identifying animals initially captured at awkward body angles. This initial trial of a basic camera system has successfully demonstrated that the ScanEagle UAV has great potential as a tool for Marine mammal aerial surveys.
Natalie Kelly - One of the best experts on this subject based on the ideXlab platform.
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unmanned aerial vehicles for surveying Marine Fauna assessing detection probability
Ecological Applications, 2017Co-Authors: Amanda Hodgson, David Peel, Natalie KellyAbstract:Aerial surveys are conducted for various Fauna to assess abundance, distribution, and habitat use over large spatial scales. They are traditionally conducted using light aircraft with observers recording sightings in real time. Unmanned Aerial Vehicles (UAVs) offer an alternative with many potential advantages, including eliminating human risk. To be effective, this emerging platform needs to provide detection rates of animals comparable to traditional methods. UAVs can also acquire new types of information, and this new data requires a reevaluation of traditional analyses used in aerial surveys; including estimating the probability of detecting animals. We conducted 17 replicate UAV surveys of humpback whales (Megaptera novaeangliae) while simultaneously obtaining a ‘census’ of the population from land-based observations, to assess UAV detection probability. The ScanEagle UAV, carrying a digital SLR camera, continuously captured images (with 75% overlap) along transects covering the visual range of land-based observers. We also used ScanEagle to conduct focal follows of whale pods (n = 12, mean duration = 40 min), to assess a new method of estimating availability. A comparison of the whale detections from the UAV to the land-based census provided an estimated UAV detection probability of 0.33 (CV = 0.25; incorporating both availability and perception biases), which was not affected by environmental covariates (Beaufort sea state, glare, and cloud cover). According to our focal follows, the mean availability was 0.63 (CV = 0.37), with pods including mother/calf pairs having a higher availability (0.86, CV = 0.20) than those without (0.59, CV = 0.38). The follows also revealed (and provided a potential correction for) a downward bias in group size estimates from the UAV surveys, which resulted from asynchronous diving within whale pods, and a relatively short observation window of 9 s. We have shown that UAVs are an effective alternative to traditional methods, providing a detection probability that is within the range of previous studies for our target species. We also describe a method of assessing availability bias that represents spatial and temporal characteristics of a survey, from the same perspective as the survey platform, is benign, and provides additional data on animal behavior.
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Unmanned aerial vehicles (UAVs) for surveying Marine Fauna: A dugong case study
PLoS ONE, 2013Co-Authors: Amanda Hodgson, Natalie Kelly, David PeelAbstract:Aerial surveys of Marine mammals are routinely conducted to assess and monitor species' habitat use and population status. In Australia, dugongs (Dugong dugon) are regularly surveyed and long-term datasets have formed the basis for defining habitat of high conservation value and risk assessments of human impacts. Unmanned aerial vehicles (UAVs) may facilitate more accurate, human-risk free, and cheaper aerial surveys. We undertook the first Australian UAV survey trial in Shark Bay, western Australia. We conducted seven flights of the ScanEagle UAV, mounted with a digital SLR camera payload. During each flight, ten transects covering a 1.3 km(2) area frequently used by dugongs, were flown at 500, 750 and 1000 ft. Image (photograph) capture was controlled via the Ground Control Station and the capture rate was scheduled to achieve a prescribed 10% overlap between images along transect lines. Images were manually reviewed post hoc for animals and scored according to sun glitter, Beaufort Sea state and turbidity. We captured 6243 images, 627 containing dugongs. We also identified whales, dolphins, turtles and a range of other Fauna. Of all possible dugong sightings, 95% (CI = 90%, 98%) were subjectively classed as 'certain' (unmistakably dugongs). Neither our dugong sighting rate, nor our ability to identify dugongs with certainty, were affected by UAV altitude. Turbidity was the only environmental variable significantly affecting the dugong sighting rate. Our results suggest that UAV systems may not be limited by sea state conditions in the same manner as sightings from manned surveys. The overlap between images proved valuable for detecting animals that were masked by sun glitter in the corners of images, and identifying animals initially captured at awkward body angles. This initial trial of a basic camera system has successfully demonstrated that the ScanEagle UAV has great potential as a tool for Marine mammal aerial surveys.
Amanda Hodgson - One of the best experts on this subject based on the ideXlab platform.
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unmanned aerial vehicles for surveying Marine Fauna assessing detection probability
Ecological Applications, 2017Co-Authors: Amanda Hodgson, David Peel, Natalie KellyAbstract:Aerial surveys are conducted for various Fauna to assess abundance, distribution, and habitat use over large spatial scales. They are traditionally conducted using light aircraft with observers recording sightings in real time. Unmanned Aerial Vehicles (UAVs) offer an alternative with many potential advantages, including eliminating human risk. To be effective, this emerging platform needs to provide detection rates of animals comparable to traditional methods. UAVs can also acquire new types of information, and this new data requires a reevaluation of traditional analyses used in aerial surveys; including estimating the probability of detecting animals. We conducted 17 replicate UAV surveys of humpback whales (Megaptera novaeangliae) while simultaneously obtaining a ‘census’ of the population from land-based observations, to assess UAV detection probability. The ScanEagle UAV, carrying a digital SLR camera, continuously captured images (with 75% overlap) along transects covering the visual range of land-based observers. We also used ScanEagle to conduct focal follows of whale pods (n = 12, mean duration = 40 min), to assess a new method of estimating availability. A comparison of the whale detections from the UAV to the land-based census provided an estimated UAV detection probability of 0.33 (CV = 0.25; incorporating both availability and perception biases), which was not affected by environmental covariates (Beaufort sea state, glare, and cloud cover). According to our focal follows, the mean availability was 0.63 (CV = 0.37), with pods including mother/calf pairs having a higher availability (0.86, CV = 0.20) than those without (0.59, CV = 0.38). The follows also revealed (and provided a potential correction for) a downward bias in group size estimates from the UAV surveys, which resulted from asynchronous diving within whale pods, and a relatively short observation window of 9 s. We have shown that UAVs are an effective alternative to traditional methods, providing a detection probability that is within the range of previous studies for our target species. We also describe a method of assessing availability bias that represents spatial and temporal characteristics of a survey, from the same perspective as the survey platform, is benign, and provides additional data on animal behavior.
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Unmanned aerial vehicles (UAVs) for surveying Marine Fauna: A dugong case study
PLoS ONE, 2013Co-Authors: Amanda Hodgson, Natalie Kelly, David PeelAbstract:Aerial surveys of Marine mammals are routinely conducted to assess and monitor species' habitat use and population status. In Australia, dugongs (Dugong dugon) are regularly surveyed and long-term datasets have formed the basis for defining habitat of high conservation value and risk assessments of human impacts. Unmanned aerial vehicles (UAVs) may facilitate more accurate, human-risk free, and cheaper aerial surveys. We undertook the first Australian UAV survey trial in Shark Bay, western Australia. We conducted seven flights of the ScanEagle UAV, mounted with a digital SLR camera payload. During each flight, ten transects covering a 1.3 km(2) area frequently used by dugongs, were flown at 500, 750 and 1000 ft. Image (photograph) capture was controlled via the Ground Control Station and the capture rate was scheduled to achieve a prescribed 10% overlap between images along transect lines. Images were manually reviewed post hoc for animals and scored according to sun glitter, Beaufort Sea state and turbidity. We captured 6243 images, 627 containing dugongs. We also identified whales, dolphins, turtles and a range of other Fauna. Of all possible dugong sightings, 95% (CI = 90%, 98%) were subjectively classed as 'certain' (unmistakably dugongs). Neither our dugong sighting rate, nor our ability to identify dugongs with certainty, were affected by UAV altitude. Turbidity was the only environmental variable significantly affecting the dugong sighting rate. Our results suggest that UAV systems may not be limited by sea state conditions in the same manner as sightings from manned surveys. The overlap between images proved valuable for detecting animals that were masked by sun glitter in the corners of images, and identifying animals initially captured at awkward body angles. This initial trial of a basic camera system has successfully demonstrated that the ScanEagle UAV has great potential as a tool for Marine mammal aerial surveys.
Brendan P. Kelaher - One of the best experts on this subject based on the ideXlab platform.
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Assessing variation in assemblages of large Marine Fauna off ocean beaches using drones
Marine and Freshwater Research, 2020Co-Authors: Brendan P. Kelaher, Andrew P. Colefax, Alejandro Tagliafico, Melanie J Bishop, Anna B. Giles, Paul A. ButcherAbstract:The turbulent waters off ocean beaches provide habitat for large Marine Fauna, including dolphins, sharks, rays, turtles and game fish. Although, historically, these assemblages have proven difficult to quantify, we used a new drone-based approach to assess spatial and temporal variation in assemblages of large Marine Fauna off four exposed beaches in New South Wales, Australia. In total, 4388 individual large Marine animals were identified from 216 drone flights. The most common taxa, bottlenose dolphins (Tursiops spp.) and Australian cownose rays (Rhinoptera neglecta), occurred in 25.5 and 19.9% of flights respectively. White (Carcharodon carcharias), bull (Carcharhinus leucas) and other whaler (Carcharhinus spp.) sharks were observed in
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assessing variation in assemblages of large Marine Fauna off ocean beaches using drones
Marine and Freshwater Research, 2020Co-Authors: Brendan P. Kelaher, Andrew P. Colefax, Alejandro Tagliafico, Melanie J Bishop, Anna Giles, Paul A. ButcherAbstract:The turbulent waters off ocean beaches provide habitat for large Marine Fauna, including dolphins, sharks, rays, turtles and game fish. Although, historically, these assemblages have proven difficult to quantify, we used a new drone-based approach to assess spatial and temporal variation in assemblages of large Marine Fauna off four exposed beaches in New South Wales, Australia. In total, 4388 individual large Marine animals were identified from 216 drone flights. The most common taxa, bottlenose dolphins (Tursiops spp.) and Australian cownose rays (Rhinoptera neglecta), occurred in 25.5 and 19.9% of flights respectively. White (Carcharodon carcharias), bull (Carcharhinus leucas) and other whaler (Carcharhinus spp.) sharks were observed in <1% of flights. There was significant variation in the structure of assemblages of large Fauna among beaches, with those adjacent to riverine estuaries having greater richness and abundance of wildlife. Overall, drone surveys were successful in documenting the spatio-temporal dynamics of an impressive suite of large Marine Fauna. We contend that emerging drone technology can make a valuable contribution to the ecological information required to ensure the long-term sustainability of sandy-beach ecosystems and associated Marine wildlife.
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The potential for unmanned aerial vehicles (UAVs) to conduct Marine Fauna surveys in place of manned aircraft
Ices Journal of Marine Science, 2017Co-Authors: Andrew P. Colefax, Paul A. Butcher, Brendan P. KelaherAbstract:Abstract Unmanned aerial vehicles (UAVs) are increasingly used in Marine wildlife research. As technological developments rapidly advance the versatility and functionality of affordable UAVs, their potential as a Marine aerial survey tool is quickly gaining attention. Currently, there is significant interest in whether cost-effective UAVs can outperform manned aircraft in aerial surveys of Marine Fauna at sea, although few empirical studies have compared relative sampling efficiency, accuracy and precision. Civil aviation restrictions, and subsequent available civilian technologies, make it unlikely that UAVs will currently be more effective than manned aircraft for large area Marine surveys. UAVs do, however, have the capacity to fill a niche for intensive smaller spatial scale sampling and for undertaking aerial surveys in isolated locations. Improvements in UAV sensor resolutions and alternative sensor types, such as multispectral cameras, may increase area coverage, reduce perception error, and increase water penetration for sightability. Additionally, the further development of auto-detection software will rapidly improve image processing and further reduce human observer error inherent in manned aerial surveys. As UAV technologies and associated methodology is further developed and becomes more affordable, these aircraft will be increasingly adopted as a Marine aerial survey tool in place of traditional methods using manned aircraft.
Cedric Gervaise - One of the best experts on this subject based on the ideXlab platform.
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Underwater operational noise level emitted by a tidal current turbine and its potential impact on Marine Fauna
Marine pollution bulletin, 2018Co-Authors: Julie Lossent, Lucia Di Iorio, Thomas Folegot, Dominique Clorennec, Morgane Lejart, Cedric GervaiseAbstract:Abstract Marine renewable energy development raised concerns over the impact of underwater noise. Here we assess the acoustic impacts of an operating tidal current turbine (Paimpol-Brehat site, France) on Marine Fauna. Its source level (SL) has been measured in situ using 19 drifting transects at distances between 100 m to 2400 m from the turbine. SL ranged from 118 to 152 dB re1 μPa@1 m in third-octave bands at frequencies between 40 and 8192 Hz. It is comparable to the SL of a 19 m boat travelling at 10kt speed. This SL was used to estimate the impact of this noise type based on acoustic propagation simulations. The acoustic footprint of the device corresponds to a 1.5 km radius disk. Our results show that within this area of greatest potential impact, physiological injury of the hearing apparatus of invertebrates, fishes and Marine mammals is improbable. Behavioral disturbance may occur up to 1 km around the device for harbor porpoises only. This is of little concern for a single turbine. However, greater concern on turbine noise impact, particularly on behavioral reactions has to be granted for a farm with up to 100 turbine. The lack of consolidated knowledge on behavioral disturbances identifies the needs for specific research programs.
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Underwater operational noise level emitted by a tidal current turbine and its potential impact on Marine Fauna
The Journal of the Acoustical Society of America, 2017Co-Authors: Julie Lossent, Cedric Gervaise, Lucia Di Iorio, Thomas Folegot, Dominique Clorennec, Morgane LejartAbstract:Marine renewable energy development raised concerns over the impact of underwater noise. We assessed the acoustic impacts of an operating tidal current turbine (Paimpol-Brehat site, France) on Marine Fauna. The turbine’s source level (SL) was estimated using 19 acoustic drifting transects at distances between 100m to 2400m from the device. SL ranges from 118 to 152dBre1μPa@1m in the third-octave bands at frequencies between 40 and 8192Hz, a noise level comparable to the one emitted by a 19m boat travelling at 10kt. The SL was used to estimate the impact of the turbine’s noise based on acoustic propagation simulations. The overall acoustic footprint of the device corresponds to a disk of 350 meters radius. Our results showed that within this footprint, physiological trauma is improbable but behavioral disturbance may occur up to 350m around the device for Marine mammals (impact limited by the footprint area), and 55m, 5m and 5m respectively for pollocks, sea basses and a shrimp species. Feedbacks from this study show that the assessment of TTS and PTS risk areas for Marine mammals is rather mature, but there are still many uncertainties about the assessment of risk areas for behavioral disturbance and masking for fishes and Marine invertebrates.Marine renewable energy development raised concerns over the impact of underwater noise. We assessed the acoustic impacts of an operating tidal current turbine (Paimpol-Brehat site, France) on Marine Fauna. The turbine’s source level (SL) was estimated using 19 acoustic drifting transects at distances between 100m to 2400m from the device. SL ranges from 118 to 152dBre1μPa@1m in the third-octave bands at frequencies between 40 and 8192Hz, a noise level comparable to the one emitted by a 19m boat travelling at 10kt. The SL was used to estimate the impact of the turbine’s noise based on acoustic propagation simulations. The overall acoustic footprint of the device corresponds to a disk of 350 meters radius. Our results showed that within this footprint, physiological trauma is improbable but behavioral disturbance may occur up to 350m around the device for Marine mammals (impact limited by the footprint area), and 55m, 5m and 5m respectively for pollocks, sea basses and a shrimp species. Feedbacks from this...