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The APH-22 hexacopter (Aerial Imaging Solutions, Old Lyme, CT) that was used to fl y 60 successful missions to collect vertical photogrammetry images of killer whales at sea. Here shown with the Olympus E-PM2 camera and interchangeable lens system; the camera mounts on the underside of the hexacopter to be downward-facing.
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Conventional aircraft have been used for photogrammetry studies of free-ranging whales, but are often not practical in remote regions or not affordable. Here we report on the use of a small, unmanned hexacopter (APH-22; Aerial Imaging Solutions) as an alternative method for collecting photographs to measure killer whales (Orcinus orca) at sea. We d...
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... aircraft have been successfully used for photogrammetry studies of free-ranging whales. Fixed-wing planes and helicopters have been used to obtain vertical photographs from directly above whales, from which shape profiles can be measured to assess body condition to infer nutritional status and pregnancy (e.g., Perryman and Lynn 2002). When combined with information on scale (= altitude/focal length), these images can also be used to estimate absolute length (e.g., Pitman et al. 2007) and monitor growth trends (e.g., Fearnbach et al. 2011). However, aircraft operations are often not practical in remote regions, and not affordable under typical research budgets, and therefore this technique has not been widely used. Here we report on a recent project using a small unmanned aerial system (UAS) as an alternative method for successfully obtaining photogrammetry images of killer whales ( Orcinus orca ) at sea. Our study area was around Vancouver Island, off the British Columbia coastline of western Canada. Previously, we used a helicopter to measure “ Southern Resident ” killer whales in the more accessible waters off Southern Vancouver Island (Fearnbach et al. 2011), but required an alternative approach to obtain comparative measurements from the “ Northern Resident ” population in the more remote area at the north of the island. We chose to use a small multi-rotor UAS because vertical takeoff and landing (VTOL) capability was required to operate from a small boat, and we required stability in flight for photographic operations. We chose a small (1.2 kg dry weight without payload; 82 cm wingspan) hexacopter that was recently used in Antarctica to obtain photographs for counting seals and penguins, and to estimate the size of leopard seals onshore (Goebel et al. 2015). This UAS platform has been proven to have the endurance and performance characteristics to conduct successful photographic missions in a windy environment, and to create a limited sound footprint that does not dis- turb wildlife. The APH-22 hexacopter (Aerial Imaging Solutions, Old Lyme, CT; Fig. 1) is described in Goebel et al. (2015); however, one key modification to firmware was required for operating from a boat, namely, the ability to store a motionless calibration of the gyro sensors made on land and recall these gyro offsets from non-volatile memory when on the boat. This enabled the hexacopter to maintain stable flight attitude, even when launched from a moving platform at sea. We successfully deployed and retrieved the hexacopter by hand during 60 flight missions launched from the upper deck of an 8.2 m SeaSport boat (Fig. 2). This procedure proved to be safe and repeatable, because of the stable flight and low weight of the hexacopter; the only payload was a camera (Olympus E-PM2, 0.23 kg; Olympus M.Zuiko 25 mm F1.8 lens, 0.13 kg) and hexacopter battery (QuadroPower 6200 mAh Lipo Flat; 0.58 kg). Wind speeds were less than 5 m/s (10 knots) during all flights, as we chose to only fly when a smooth sea state would enable detailed images of whales beneath the surface. The average duration of the 60 flights was 13.2 min (max = 15.7 min). These marine flights were conservatively ended well in advance of battery limitations — the APH-22 has been flown for >25 min during test flights with the same battery. The total distance covered during a flight averaged 1350 m (max = 2480 m), but the distance to the pilot was smaller (typically <200 m) as the boat was continuously maneuvered to enable line-of-sight piloting of the hexacopter and facilitate positioning over whales. The hexacopter was controlled by the pilot using a radio link (2.4 GHz), and we did not experience any loss of link during the 13.25 h of total flying. Finer-scale positioning of the hexacopter above whales was accomplished through guidance from a ground station operator who viewed live analog video captured by the onboard camera and transmitted to a portable monitor on the boat using a 5.8 GHz link. When whales were in the frame, the pilot used a remote link to trigger the cap- ture of high-resolution (12.3 MP) still images on the camera ’ s flash memory. The ground station also displayed telemetry information (910 MHz link), which enabled monitoring of altitude, flight time, and battery levels for flight management. We were successful at positioning the hexacopter directly above groups of killer whales, and obtained a total of 18920 still images from an altitude of 35 – 40 m. We did not observe any behavioral responses from the whales during any of the flights, and they likely were not aware of the small hexacopter at these altitudes. The 25 mm lens we used is considered “ normal ” for the Micro Four-Thirds sensor of the E-PM2 camera, in that the focal length is equal to the diagonal of a square formed by the long dimension of the sensor, and therefore photogrammetry measurements were possible across the full extent of a flat and undistorted field of view. Previous resolution tests over a standard medium contrast (8:1) resolution target (RST-704, series C) showed that we had a ground-resolved distance of <1.8 cm using the 25 mm lens at an altitude of 50 m, which improved further to <1.4 cm at our standard altitude of 35 m. Our images of the whales clearly showed that this expected resolution was rea- lized in photographs at sea: notably, we could resolve differences in natural markings to identify individual whales using images of their saddle patch pigmentation (Fig. 3), which allowed us to link measurements to whales of known age and sex (e.g., Fearnbach et al. 2011). One of the key requirements of our photogrammetry system is the ability to obtain whale length and width profiles on a real scale. Measurements from the images in pixels can be converted to a true measurement using the known longitudinal dimension of the camera sensor and the number of pixels comprising this known width, and these can then be scaled to true lengths using the measured altitude and the focal length of the lens (e.g., Fearnbach et al. 2011). The flight controllers on the hexacopter used a Freescale MPX4115A absolute air pressure sensor, which has on-chip temperature compensation, for altitude measurements. We calculated the altitude of the hexacopter at 1 s intervals by applying the standard altitude equation to the difference between the pressure while flying and the pressure at takeoff, with a known takeoff height above sea level. Onboard measures of altitude were validated by scale calculations of the distance between points of known separation (6.4 m = approximate whale length) on the deck of our research vessel, measured from photographs taken at our standard photogrammetry altitudes. Using 16 different calibration photographs from calculated altitudes of 35 – 38 m, the average bias was − 0.05 m (standard deviation = 0.29 m), representing <1% of the total length of the boat. This indicated the ability to monitor absolute size and growth of whales with precision, which is demonstrated in Fig. 4 by estimated length differences among seven whales of varying ages within the “ I16 matriline ” (family group) of killer whales. These whales ranged in ages between a first year calf and a 45 year old adult female at the time of the photograph in 2014, with estimated lengths ranging from 2.6 to 5.8 m from this particular image. At the time of writing, work is underway to identify and measure all the whales in this large photographic sample, and further data collection is planned to quantitatively monitor individual whale growth and body condition into the future. This first, and very successful, field effort at sea has demonstrated the APH-22 hexacopter to have great utility for collecting photogrammetry images to fill key scientific data gaps about free ranging whales. It is a small and portable aircraft with VTOL capability that enables safe deployment and retrieval from even small boat platforms, and therefore enables aerial photogrammetry in remote locations where conventional aircraft are impractical. It is quiet and stable in flight, and can therefore be flown at relatively low altitudes without disturbing whales. As a result, we can obtain high-resolution images that are sharp enough to differentiate individual whales using natural markings, with precise altitude to enable quantitative measurements. We anticipate that these advantageous features will provide a cost-effective option for studies of wildlife populations in general, not just whales. Hexacopter flights were authorized by a Special Flight Operations Certificate from Transport Canada and approaches to whales by both the boat and hexacopter were authorized by Research License issued by Fisheries and Oceans Canada (2014-5 SARA-327). J. Borrowman helped with field logistics, C. Crossman facilitated project planning, and J. Towers assisted with identifying known whales from aerial images. Field costs were supported by a grant from the Seaworld & Busch Gardens Conservation Fund. Development of the hexacopter was performed under a grant from NOAA ’ s Office of Marine and Aviation Operations, and through the support of Commander M.J. Silah, ...
Citations
... It is likely that multiple factors affect the accurate estimate of coastal juvenile shark habitat and nursery areas. While the use of drones has proven useful for studying the coastal habitats of many marine animals (Durban et al., 2015;Hodgson, Kelly & Peel, 2013;Kiszka et al., 2016;Rieucau et al., 2018), their practicality needs to be tested within the Galápagos as a potential tool for long-term coastal habitat survey use. The presence of these potential nursery areas within the coastal oligotrophic waters of San Cristobal Island makes these areas a prime region for preliminary UAV abundance studies of juvenile 2 | MATERIALS AND METHODS ...
New approaches to abundance surveying utilizing unoccupied aerial vehicles (UAVs) are proving to be effective tools in marine and terrestrial environments. We explored UAV efficacy for surveys in the Galapagos Marine Reserve (GMR), where relative abundance patterns of juvenile sharks and subsequent classifications of putative nursery areas based on environmental drivers are lacking. The UAV method allowed greater temporal and spatial coverage. We expanded classification of shark nursery habitat through monthly drone surveys and environmental data collection at 14 sites around San Cristobal Island (GMR) from November 2018 to July 2019. In the period of surveying, 56 flights identified 453 juvenile Carcharhinus limbatus (blacktip shark). Classification of nurseries followed three criteria, necessitating higher density, short‐term residency, and annual site fidelity in target locations. We developed preliminary generalized linear models to elucidate potential environmental parameters influencing the perceived abundance and habitat preference of juveniles. Four sites were identified as either potential nurseries or nursery areas for the target species based on previous excursions. An averaged model was subsequently created from the models found to best explain deviance patterns (R² = 0.10–0.44) in perceived shark abundance and habitat preference. Relative variable importance (RVI) values further clarified the parameters most associated with higher juvenile presence. This approach provides a systematic method of abundance surveying while simultaneously beginning the process of defining when and where we expect to find higher abundance through environmental modelling of most influential parameters to perceived abundance in this environment.
... The rapid development of domestically available and more affordable unoccupied aerial systems (hereafter UASs or drones) has enabled the advancement of research studies using aerial data (Fiori et al., 2017;Johnston, 2019;Álvarez-González et al., 2023). A variety of cetacean species have been identified using aerial images taken by drones, including bottlenose dolphins (Cheney et al., 2022), Risso's dolphins (Grampus griseus; Hartman et al., 2020), Australian snubfin (Orcaella heinsohni) and Australian humpback (Sousa sahulensis) dolphins (Christie et al., 2021), pygmy killer whales (Feresa attenuata; Currie et al., 2021), belugas (Delphinapterus leucas; Ryan et al., 2022), long-finned pilot whales (Globicephala melas; Zwamborn et al., 2023), killer whales (Durban et al., 2015), dwarf sperm whales (Kogia sima; Baird et al., 2021), Antarctic minke whales (Balaenoptera bonaerensis; Pallin et al., 2022), North Atlantic right whales (Martins et al., 2020), southern right whales , gray whales (Eschrichtius robustus; Christiansen et al., 2021), bowhead whales (Koski et al., 2015), humpback whales (Napoli et al., 2024), fin whales (Balaenoptera physalus; Degollada et al., 2023), and blue whales (Balaenoptera musculus; Ramp et al., 2021). ...
Photo-identification is a staple tool used in cetacean conservation studies since the 1970s to monitor individuals on a regional and ocean basin-wide scale to infer critical information about habitat use, suitability, and shifts. This technique has been extensively used on sperm whales globally since it was developed in 1982, initially using the tail fluke from deep diving whales and the dorsal fin when appropriate. From the mid 2010s onwards, the emergence of domestically available unoccupied aerial systems (drones) has reshaped how whale research can be conducted. Herein, we describe the suitability of aerial images to determine the identity of individual sperm whales (Physeter macrocephalus) using all available identifiable markings along their dorsal side to complement the use of fluke notches and dorsal fin scars photographed from the surface of the sea from boat-based platforms for photo-identification and to maximize opportunities to identify and monitor sperm whales. Drone data were gathered while flying over sperm whales in Andenes, Norway; Shetland, Scotland; Dursey Island, Ireland; and Faial and São Miguel Islands, Azores, Portugal, between 2017 and 2024, which enabled the entire dorsal surface of sperm whales to be captured and assessed. Aerial photographs and videos were used to differentiate between 336 individual sperm whales using physical characteristics. We identified the main features of sperm whales through aerial drone images, as well as their prevalence in Atlantic high latitude foraging grounds and lower latitude nursery grounds. We discuss the advantages of using aerial drone photographs to identify sperm whales in addition to traditional boat-based photo-identification.
... Despite the valuable information that body condition provides about individual and population health, monitoring the body condition of free-ranging cetaceans has historically been challenging because most species are highly difficult or impossible to capture depending on size, spend the majority of their time submerged underwater, and present limited opportunities for visual examination when they surface briefly to breathe (Nowacek et al., 2016). In the past decade, unmanned aerial systems (UASs), also known as drones, have emerged as a popular and powerful tool that have revolutionized how free-ranging cetaceans are studied in the wild (Durban et al., 2015). Compared to traditional cetacean health assessment methods such as boat-based surveys, manned aircraft surveys, and live capture-release health assessments, UASs are relatively inexpensive, easy to transport and use in the field, can access remote areas that otherwise are difficult to monitor, and are minimally stressful to the animal due to their noninvasive nature (Hodgson et al., 2016;Atkinson et al., 2021). ...
... The DJI Air 2S was primarily chosen as the UAS model due to available resources and its being relatively inexpensive (~$1,000 USD). Most UAS cetacean body condition studies have used higher-quality and more expensive UAS models such as the DJI Phantom 3 or 4 Pro (Burnett et al., 2018;Lemos et al., 2020;Arranz et al., 2022;Christie et al., 2022;Torres et al., 2022;de Oliveira et al., 2023), an APH-22 hexacopter (Durban et al., 2015(Durban et al., , 2016Christiansen et al., 2020;Fearnbach et al., 2020;Stewart et al., 2021), or a DJI Inspire 1 or 2 equipped with a Zenmuse X5 camera (Christiansen et al., 2018(Christiansen et al., , 2020(Christiansen et al., , 2021Arranz et al., 2022;Bierlich et al., 2022;Serres et al., 2024). As a result, previous studies of small cetaceans have been able to fly at higher altitudes (15 to 60 m) while still collecting high-quality images that can be used for photogrammetry and body condition assessment (Arranz et al., 2022;Cheney et al., 2022;Christie et al., 2022;de Oliveira et al., 2023;Serres et al., 2024). ...
... However, the main goal of this study was to assess dolphin body condition in the CES, so accurate body measurements would not have been any better than the BAI body ratio for this purpose (Serres et al., 2024). If estimated morphometric measurements are desired for future studies, a UAS with lower measurement uncertainty should be used or a laser altimeter should be attached to the DJI Air 2S (Durban et al., 2015(Durban et al., , 2016Dawson et al., 2017;Christiansen et al., 2018Christiansen et al., , 2020Christiansen et al., , 2021Bierlich et al., 2022;Ramos et al., 2022;Torres et al., 2022). For body condition assessment, the DJI Air 2S did have a higher mean measurement uncertainty for BAI (CV = 1.12%) compared to other higher-quality UASs used in baleen whale body condition studies such as the Inspire 1 Pro (CV = 0.12%) and the Phantom 4 Pro (CV = 0.91%), although it was lower than the measurement uncertainty associated with BAI for the Phantom 4 and the Phantom 3 Pro (CV = 2.97%) Torres et al., 2022). ...
Body condition is a measure of an animal’s energy reserves relative to its body structure that provides important information about individual- and population-level health. Monitoring the body condition of free-ranging cetaceans has historically been difficult, but in recent years, the unmanned aerial system (UAS, or “drone”) has facilitated noninvasive ways of estimating the cetacean body condition. The Charleston Estuarine System (CES) includes the estuarine and coastal ecosystems surrounding Charleston, South Carolina, and is utilized by Tamanend’s bottlenose dolphins (Tursiops erebennus) throughout the year. The main goals of this study were (1) to test if UASs are suitable for monitoring body condition of dolphins in an estuarine environment, and (2) to determine if site, season, and age class influence the body condition of dolphins in the CES. Land-based UAS surveys were conducted at four sites throughout the CES between September 2022 and May 2023. The body condition of each dolphin was evaluated using images of the individual positioned flat with a straight body at the surface, and a linear mixed effects model was constructed to determine which effects were associated with significant differences in dolphin body condition. After filtering images for quality, 428 images of 174 unique dolphins were included in the final analysis, with repeated body condition estimates of 24 dolphins from multiple seasons. Both season and age class were significant predictors of dolphin body condition, but site was not. In addition, individual dolphins were catalogued in a Drone Dolphin ID database, which allowed some dolphins’ unique body condition changes to be tracked over time. These findings provide an important baseline for dolphin body condition in the CES that can be built upon in future studies to better understand how body condition changes in response to environmental and anthropogenic stressors or for different age classes.
... The integration of fine-scale spatial movement sampling builds on the increasing application of unoccupied aerial systems (UAS) in studying cetaceans (e.g. [29][30][31]). ...
... However, this potential effect was controlled for as flights were made at similar altitudes during MFAS transmission (see below for description) experiments (median: 60 m; range: 50-68) and no-sonar control trials (median: 61 m; range: 57-67). The drone carried a vertically gimballed camera (at least 16 megapixels) and sensors that allowed precise geolocation of photographed dolphins, allowing spatially explicit photogrammetry to infer movement speed and directionality [28,29]. Photogrammetry images were collected every second, but speed and directionality parameters were modelled in 5 s blocks to match passive acoustic monitoring (PAM) data analysis (described below). ...
Despite strong interest in how noise affects marine mammals, little is known for the most abundant and commonly exposed taxa. Social delphinids occur in groups of hundreds of individuals that travel quickly, change behaviour ephemerally and are not amenable to conventional tagging methods, posing challenges in quantifying noise impacts. We integrated drone-based photogrammetry, strategically placed acoustic recorders and broad-scale visual observations to provide complementary measurements of different aspects of behaviour for short- and long-beaked common dolphins. We measured behavioural responses during controlled exposure experiments (CEEs) of military mid-frequency (3–4 kHz) active sonar (MFAS) using simulated and actual Navy sonar sources. We used latent-state Bayesian models to evaluate response probability and persistence in exposure and post-exposure phases. Changes in subgroup movement and aggregation parameters were commonly detected during different phases of MFAS CEEs but not control CEEs. Responses were more evident in short-beaked common dolphins (n = 14 CEEs), and a direct relationship between response probability and received level was observed. Long-beaked common dolphins (n = 20) showed less consistent responses, although contextual differences may have limited which movement responses could be detected. These are the first experimental behavioural response data for these abundant dolphins to directly inform impact assessments for military sonars.
... Researchers have flown UAVs at relatively high altitudes (35-40 m) to collect photogrammetry data from Southern Resident killer whales (SRKWs) and mammal-eating transient/Bigg's killer whales (Durban et al., 2015;Fearnbach et al., 2019;Kotik et al., 2023) without noting behavioral responses (Durban et al., 2015). To collect breath from killer whales, however, UAVs must be flown as low as 3 m. ...
... Researchers have flown UAVs at relatively high altitudes (35-40 m) to collect photogrammetry data from Southern Resident killer whales (SRKWs) and mammal-eating transient/Bigg's killer whales (Durban et al., 2015;Fearnbach et al., 2019;Kotik et al., 2023) without noting behavioral responses (Durban et al., 2015). To collect breath from killer whales, however, UAVs must be flown as low as 3 m. ...
... Subsequently, long range, fixed-wing RPAs have been used for line and strip transect surveys to derive cetacean abundance estimates (Hodgson et al., 2017) including in extreme environments (Aniceto et al., 2018) and also for research on Antarctic wildlife (Zmarz et al., 2018;Pfeifer et al., 2019;Pina and Vieira, 2022) and the physical Antarctic environment (Bello et al., 2022;Pina and Vieira, 2022). In addition to using RPAs to undertake aerial surveys (Angliss et al., 2018), RPAs and multirotor RPAs in particular, have been employed as a cetacean research tool to undertake photogrammetry (Durban et al., 2015;Christiansen et al., 2018), collect photo identification images (Koski et al., 2015;Ryan et al., 2022;Young et al., 2022), investigate energetics and kinematics Werth et al., 2019), sample whale blow (Apprill et al., 2017;Pirotta et al., 2017), assess anthropogenic interactions (Ramp et al., 2021;Pirotta et al., 2022), sample faecal matter (Baird et al., 2022) and undertake behavioural observation (Torres et al., 2018;Fiori et al., 2020). ...
Data collection facilitated by remotely piloted aircraft (RPA) has proven to be revolutionary in many disciplines including for research in extreme environments. Here we assess current use and utility of small multirotor remotely piloted aircraft (RPAs) for the challenging role of facilitating ship-based cetacean research in Antarctica. While such aircraft are now used routinely in sheltered environments in and off Antarctica, a comprehensive literature review found that RPA-mediated cetacean research conducted from ships at sea and outside of the Antarctic Peninsula region was relatively uncommon. In order to determine the potential utility of ship-based multirotor RPA operations for cetacean research, we repeatedly deployed small RPAs during a multidisciplinary research voyage in maritime East Antarctica to collect scientific data contributing to an understanding of krill and krill predator interactions. RPA flight metrics (duration, height, length, speed, distance from ship, battery drainage, satellites acquired) were compared to ship underway environmental sampling data. At a mean duration of 12 minutes, these 139 RPA flights were relatively short yet adequate to achieve the science intended, namely a range of cetacean related data streams including photogrammetry, photo identification, behavioural observations and whale blow sampling in addition to water sampling and collection of general scenic imagery. RPA flight operations were constrained by wind speed but not by air temperature with flights undertaken throughout the full range of air temperatures experienced (down to –9.5°C) but not throughout the full range of wind speeds experienced. For a 12-minute flight duration, battery drainage was around 60% indicating that the RPAs were rarely pushed to their operational limit. There was little evidence that the cold impacted RPA lithium battery performance with estimated maximum flight time within approximately 10% of expected flight time for the RPA platforms most used. Whist small multirotor RPAs are rarely applied to cetacean related research in maritime East Antarctica, we demonstrate their value and potential to deliver data critical to address knowledge gaps that challenge the effective management of both krill and their predators.
... time, besides providing permanent visual, georeferenced records of wildlife sightings (Principe et al., 2023). Drones used in cetacean studies have increasingly played a fundamental role in assessing animal abundance, spatial distribution, and behavior, in photo-identification, age estimates, sex identification, and pregnancy diagnosis processes, in biological sample collection in spray, as well as in photogrammetric assessments of body conditions (Acevedo-Whitehouse et al., 2010;Cheney et al., 2022;Christie et al., 2022;Durban et al., 2015;Goebel et al., Recent advances in drones has significantly enhanced opportunities for scientists in a wide range of disciplines to collect high-resolution aerial imagery (Bierlich et al., 2024). Photogrammetric methods comprise the technique and equipment used to take measurements based on photographs (Ortega-Ortiz et al., 2022). ...
... Similar altitudes (25-30 m) were successfully adopted in other studies to measure and/or monitor different cetacean species (Aniceto et al., 2018;Burnett et al., 2019;de Oliveira et al., 2023;Fettermann et al., 2019;Fiori et al., 2019). The calibration model based on a known-scale object allowed applying a correction factor to help reduce likely inaccuracies in morphological measurements, as is done with traditional aerial photogrammetry protocols (Burnett et al., 2019;Christiansen et al., 2016;de Oliveira et al., 2023;Durban et al., 2015;Jaquet, 2006;Ratsimbazafindranahaka et al., 2022). ...
Monitoring and assessing cetaceans through non-invasive methods may be used as shortcut to help improving knowledge about these species; many of them are endangered species. The current study was the first to collect and analyze aerial morphological measurements taken from odontocete calves and spinner dolphin (Stenella longirostris) species. Aerial photogrammetry data were collected from oceanic spinner mother-calf pairs swimming together, at a shallow rest bay called “Biboca”, around Fernando de Noronha Archipelago, Brazil. Estimated body length (EBL), anterior width of pectoral fin (PEC), width at the axilla (AXI) and body condition indices (PECidx and AXLidx) were the morphometric measurements adopted. The herein adopted aerial protocol was accurate in identifying temporal body condition variations in calves over 106 days without any disturbing behavior potentially associated with the presence of the drone registered throughout the study. The results added new limits to the current morphological local knowledge by registering a 201 cm-long adult individual and a 78 cm-long newborn dolphin. The aerial protocol can be used to assess calf growth patterns in small cetacean species, which, in their turn, can be indicators of cetaceans’ individual and population health, mainly in environments threatened by human activities, like the one in Fernando de Noronha Archipelago.
... Although drones require additional up-front costs, permitting, and technical training, they can be more cost-effective and safer than "occupied" aerial observation methods over the longer-term. Drones are increasingly employed to study marine species and have been used to monitor cetacean body condition, assess feeding strategies, and collect blow samples for research (e.g., de Oliveira et al., 2023;Durban et al., 2015;Geoghegan et al., 2018;Pirotta et al., 2017;Torres et al., 2020). Drones have also been used to conduct population counts on pinniped colonies (Seymour et al., 2017), survey beaches for sea turtle nesting in remote locations (Sykora-Bodie et al., 2017), and identify stranded marine birds and sea turtles (Pontalti & Barreto, 2022). ...
Stranded marine mammals provide valuable insight into population health of free‐ranging conspecifics; however, the likelihood of carcass detection by the public or trained observers is not well known. To better understand carcass detection rates (CDR), we placed twelve decoy dolphin carcasses around Dauphin Island, Alabama, for 2 weeks, one during peak tourist season and one during the off season. Decoys were placed in regions representing different habitat types (marsh or beach) and levels of human use (low or high). Calls from the public were recorded, and trained observers actively searched for decoys via drone and visual observation either by vessel or UTV and walking. There were 2.5 times more public reports during the peak ( n = 38) compared to off season ( n = 15), with most reports being from the high‐traffic beach site during peak season ( n = 27). Trained observers found more decoys (CDR = 0.88) than the public (CDR = 0.58), however, the public found two decoys that observers did not. Drone searches were slightly more successful (CDR = 0.83) than other methods (CDR = 0.79). Our results indicate that a combination of surveillance methods will enhance carcass detection, and our novel methods can be used across habitat types to improve stranding surveillance, better estimate stranding rates, and inform mortality estimates of many species.
... Due of its better lifting capacity. Hexa-copter is used for transportation applications [46], [47], agriculture applications [48], monitoring crops [49], water quality measurements [50], surveillance systems [51] and energy harvesting [52]. ...
The industry has been significantly enhanced by recent developments in UAV collision avoidance systems. They made collision avoidance controllers for self-driving drones both affordable and hazardous. These low-maintenance, portable devices provide continuous monitoring in near-real time. It is inaccurate due to the fact that collision avoidance controllers necessitate trade-offs regarding data reliability. Collision avoidance control research is expanding significantly and is disseminated through publications, initiatives, and grey literature. This paper provides a concise overview of the most recent research on the development of autonomous vehicle collision avoidance systems from 2017 to 2024. In this paper, the state-of-the-art collision avoidance system used in drone systems, the capabilities of the sensors used, and the distinctions between each type of drone are discussed. The pros and cons of current approaches are analyzed using seven metrics: complexity, communication dependency, pre-mission planning, resilience, 3D compatibility, real-time performance, and escape trajectories.
... Aerial photogrammetry is currently considered a very useful tool because this technique is noninvasive, and allows working on large numbers of animals over long periods of time, therefore enabling long-term monitoring of populations (Burnett et al., 2019). Aerial photogrammetry has already been shown to be reliable in several cetacean species including blue whales (Balaenoptera musculus, Leslie et al., 2020), gray whales (Eschrichtius robustus, Burnett et al., 2019), humpback whales (Megaptera novaeangliae, Christiansen et al., 2016), southern right whales (Eubalaena australis, Christiansen et al., 2018), sperm whales , killer whales (Orcinus orca, Durban et al., 2015Durban et al., , 2016Fearnbach et al., 2018), short-finned pilot whales (Globicephala macrorhynchus; Noren et al., 2019), or pygmy sperm whales (Currie et al., 2021). Studies are scarcer for species that have smaller body sizes, probably due to the higher difficulty to find and follow animals, but also to their behavior that differs from larger whales (e.g., rapid movements, frequent breaching and arching, and acute reaction to UAV presence, Raoult et al., 2020). ...