Gentle Giants in Dark Waters: Using Side-Scan Sonar for Manatee Research

Gonzalez‐Socoloske, Daniel

doi:10.2174/1875413901205010001

Cited by 31 publications

(34 citation statements)

References 37 publications

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“…We used high‐resolution, dual‐channel, side‐scan sonar (Imagenex Technology, Port Coquitlam, BC, Canada; YellowFin Model 872) fixed 60 cm below the waterline near the starboard bow of a 5‐m inflatable boat (Avon, Dafen, South Wales, UK). The boat was powered by a 4‐stroke outboard motor and navigated along the river's centerline (i.e., equidistant by visual reckoning to the two banks), at speeds of 5.5 to 9.3 km/hr, slightly faster than other surveys in the region using smaller sonar equipment (Gonzalez‐Socoloske and Olivera‐Gómez , Brice ). The sonar was operated at 330 kHz and 770 kHz, following the suggestion of Jaffe et al () that a frequency higher than 171 kHz reliably detects manatees.…”

Section: Methodsmentioning

confidence: 99%

“…Images were checked later in the laboratory to confirm animals and reject false‐positives made in situ . All surveys were made by the same personnel, experienced at differentiating rocks, tree roots, branches, and logs from the unique peanut‐shaped shadow of manatees (Gonzalez‐Socoloske and Olivera‐Gómez , Brice ). The Animal Care and Use Committee of the Smithsonian Tropical Research Institute approved all procedures used in the work.…”

Section: Methodsmentioning

confidence: 99%

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Abundance of manatees in Panama estimated from side‐scan sonar

Guzmán

Condit

2017

Wildl. Soc. Bull.

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The Antillean manatee (Trichechus manatus manatus) is found in tropical and subtropical riverine and coastal waters across the Caribbean region. Little is known of its population status, particularly in Central America. We counted and mapped manatees using side‐scan sonar in the San San Pond Sak wetland, a protected estuary in western Panama, for 12 months, and converted the sightings into density and abundance estimates. A total of 214 sonar transects, covering 1,731 km and detecting 1,004 manatees, were completed. The greatest density of animals was found in the narrow and relatively deep upstream tributaries and also in a shallow lagoon near the river mouth. The estimated mean number of manatees in the 18‐km San San River system over the year was 18.3, but abundance was highly seasonal, with 33 animals present in May and just 2 animals in December. These figures are within the range reported for similar rivers in Central America and Florida, USA. Uncertainty of the population size was estimated with a Bayesian model, using daily variance in counts, and 95% credible intervals were 22–71 animals at peak season but just 1–6 animals in December. The active sonar survey used in this study located manatees, mapped their positions, and converted sightings into quantitative data for rigorous analysis. The method is cost‐effective for repeated counts across seasons and years, needed to evaluate population trends. © 2017 The Wildlife Society.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Abundance of manatees in Panama estimated from side‐scan sonar

Guzmán

Condit

2017

Wildl. Soc. Bull.

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“…However, accelerated development of active sonar systems for the subsea monitoring of potential security threats for the defence sector, and for fisheries research and management, provides a basis for tracking animal movements and monitoring avoidance or evasion behaviour of animals around tidal turbines (Hastie et al, 2014). Benoit-Bird & Au, 2003a;Doksaeter, Godo, Olsen, Nottestad, & Patel, 2009;Gonzalez-Socoloske & Olivera-Gomez, 2012;Nøttestad, Ferno, & Axelsen, 2002;Pyć, Geoffrey, & Knudsen, 2016) to track the movements of individual animals in a range of different habitats. Active sonar has been used extensively in studies of marine mammal behaviour underwater (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…The fundamentals of all active sonar systems are essentially the same; pulses of sound ('pings') are produced electronically underwater using a sonar projector and the system then monitors for echoes of these pulses as they reflect off objects using a series of hydrophones (Hastie et al, 2014). Furthermore, West Indian manatee (Trichechus manatus) behaviour was measured in waters with very poor visibility (due to turbidity and sediment load) using a range of side-scan sonar systems (Gonzalez-Socoloske, Olievera-Gomez, & Ford, 2009;Gonzalez-Socoloske & Olivera-Gomez, 2012), and bottlenose dolphin (Tursiops truncatus) movements were tracked in high tidal flows using a 455 kHz Reson Seabat 6012 (Ridoux et al, 1997). Benoit-Bird & Au, 2003a;Doksaeter, Godo, Olsen, Nottestad, & Patel, 2009;Gonzalez-Socoloske & Olivera-Gomez, 2012;Nøttestad, Ferno, & Axelsen, 2002;Pyć, Geoffrey, & Knudsen, 2016) to track the movements of individual animals in a range of different habitats.…”

Section: Introductionmentioning

confidence: 99%

Automated detection and tracking of marine mammals: A novel sonar tool for monitoring effects of marine industry

Hastie

Moss

et al. 2019

Aquatic Conservation

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1. Many marine industries may pose acute risks to marine wildlife. For example, tidal turbines have the potential to injure or kill marine mammals through collisions with turbine blades. However, the quantification of collision risk is currently limited by a lack of suitable technologies to collect long-term data on marine mammal behaviour around tidal turbines.2. Sonar provides a potential means of tracking marine mammals around tidal turbines. However, its effectiveness for long-term data collection is hindered by the large data volumes and the need for manual validation of detections. Therefore, the aim here was to develop and test automated classification algorithms for marine mammals in sonar data.3. Data on the movements of harbour seals were collected in a tidally energetic environment using a high-frequency multibeam sonar on a custom designed seabedmounted platform. The study area was monitored by observers to provide visual validation of seals and other targets detected by the sonar.4. Sixty-five confirmed seals and 96 other targets were detected by the sonar. Movement and shape parameters associated with each target were extracted and used to develop a series of classification algorithms. Kernel support vector machines were used to classify targets (seal vs. nonseal) and cross-validation analyses were carried out to quantify classifier efficiency.5. The best-fit kernel support vector machine correctly classified all the confirmed seals but misclassified a small percentage of non-seal targets (~8%) as seals. Shape and non-spectral movement parameters were considered to be the most important in achieving successful classification.6. Results indicate that sonar is an effective method for detecting and tracking seals in tidal environments, and the automated classification approach developed here provides a key tool that could be applied to collecting long-term behavioural data around anthropogenic activities such as tidal turbines.

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“…For example, Nøttestad, Ferno, Mackinson, Pitcher, and Misund () used a 95 kHz Simrad SA 950 multibeam sonar to measure the behaviour of fin whales ( Balaenoptera physalus ) foraging on herring schools, and Benoit‐Bird and Au () used a 200 kHz Kongsberg SM2000 to locate and track spinner dolphins in the water column in Hawaii. Further, West Indian manatee ( Trichechus manatus ) behaviour was measured in waters with very poor visibility (due to turbidity and sediment load) using a range of sonar systems (Gonzalez‐Socoloske, Olievera‐Gomez, & Ford, ; Gonzalez‐Socoloske & Olivera‐Gomez, ), and bottlenose dolphin ( Tursiops truncatus ) movements were tracked in high tidal flows using a 455 kHz Reson Seabat 6012 (Ridoux et al, ).…”

Section: Introductionmentioning

confidence: 99%

Three‐dimensional movements of harbour seals in a tidally energetic channel: Application of a novel sonar tracking system

Hastie

Bivins

Coram

et al. 2019

Aquatic Conservation

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Understanding how marine predators utilize habitats requires that we consider their behaviour in three dimensions. Recent research has shown that marine mammals often make use of tidally energetic locations for foraging, yet data are generally limited to observations of animals at the water surface. Such areas are also of interest to the renewable energy industry for the deployment of tidal‐stream energy turbines; this has led to concerns about potential impacts on marine mammals. Methods for measuring animal movements underwater are limited; however, active sonar can image marine mammals and could potentially measure three‐dimensional movements in tidally energetic locations. Here, a dual 720 kHz sonar system was developed to investigate the three‐dimensional movements of harbour seals (Phoca vitulina) in a tidally energetic channel. Estimated mean depth (distance from the surface) of seals was 12.0 m (95% confidence intervals [CIs]: 11.6–12.4 m), and the majority of time was spent at the surface and at approximately 10–12 m distance from the surface. When expressed as distances from the sea bed, mean distance was 18.5 m (95% CI: 18.0–18.9 m), and the majority of time was spent at 14 m from the sea bed. Seal movements were generally in the same direction as the tidal flow with mean horizontal speeds of between 0.51 and 3.13 m s−1 (95% CIs = 1.24–1.54 m s−1). Mean vertical velocities (where negative and positive values represent a descent and ascent respectively) for each seal track ranged between −1.76 and +0.88 m s−1 (95% CIs: −0.23 to +0.03 m s−1). These results provide a basis for understanding how seals utilize a dynamic tidal environment and suggest that harbour seal behaviour can be markedly different to less tidally energetic habitats. The results also have important implications for the prediction of risk associated with interactions between diving seals and tidal turbines in these dynamic habitats.

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Gentle Giants in Dark Waters: Using Side-Scan Sonar for Manatee Research

Cited by 31 publications

References 37 publications

Abundance of manatees in Panama estimated from side‐scan sonar

Abundance of manatees in Panama estimated from side‐scan sonar

Automated detection and tracking of marine mammals: A novel sonar tool for monitoring effects of marine industry

Three‐dimensional movements of harbour seals in a tidally energetic channel: Application of a novel sonar tracking system

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