Preliminary analysis of echolocation signals produced by fleeing Irrawaddy dolphins (Orcaella brevirostris)

Jiang, Ying; Zhang, Xuelei; Yang, Zhiguo; Jaaman, Saifullah Arifin; Xu, Qinzeng; Muda, Azmi Marzuki; Muhamad, Hairul Masrini

doi:10.1007/s13131-019-1373-y

Cited by 6 publications

(4 citation statements)

References 8 publications

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“…The Indo-pacific humpback tends to be calm or ignore the surrounding boat and people. The Irrawaddy was more perceptive toward surrounding boats and people (Jiang et al 2019). It shows that both species have different types of preferences for their habitat and reaction toward human anthropogenic activities.…”

Section: Dolphin Hotspotmentioning

confidence: 95%

Identifying the hotspot area of Indo-Pacific humpback (Sousa chinensis) and Irrawaddy (Orcaella brevirostris) dolphins in Matang waters, Perak, Malaysia

et al. 2022

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Abstract. Sobri MF, Jaaman SA, Mohamed Z, Muda AM, Rashid MASA, Zhang X. 2022. Identifying the hotspot area of Indo Pacific humpback (Sousa chinensis) and Irrawaddy (Orcaella brevirostris) dolphins in Matang waters, Perak, Malaysia. Biodiversitas 23: 6106-6113. The Indo-Pacific humpback (Sousa chinensis) and Irrawaddy (Orcaella brevirostris) dolphins are commonly found in Matang waters, Perak, Malaysia. The area, filled with healthy mangrove forest cover and many estuaries, is not only frequented by the dolphins for its daily activities but also extensively used by locals for artisanal fishing, charcoal production and organizing ecotourism activities. There could be a high risk of human-dolphin interactions, hence determining habitat use and identifying critical habitats or "hot spots" for the dolphins in the area is important. In this study, a series of dedicated boat sighting surveys were conducted from March 2019 to January 2021 between Kuala Gula and Kuala Jarum Mas. The total survey effort was 3325.76 km, 44 days and 239.38 hours. A total of 69 dolphin sightings were made, consisting of 40 Indo-Pacific humpback dolphins and 29 Irrawaddy dolphin observations, respectively. During each sighting, every dolphin's behaviors were categorized as: foraging, socializing, evasive, and travelling, and the survey area was classified into four blocks. The results indicated that different dolphin species have different hotspot areas. For Indo-Pacific humpback dolphins, the hotspot area was Kuala Sangga, while the Irrawaddy dolphin's hotspot area was outside Kuala Larut, and there was a small overlap between the two dolphins' hotspots. Among the recorded behaviors (n: 281) for both dolphins, the most dominant was foraging (72.24%), followed by socializing (17%), evasive (7%), and travelling (4%). The sighted foraging behavior for both dolphin populations was dominant, indicating the hot spots were major foraging grounds for the two dolphin populations. This study shows the importance of Matang waters as a conservation area for the species and warrants further studies of dolphin population ecology to be conducted.

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Section: Dolphin Hotspotmentioning

confidence: 95%

Identifying the hotspot area of Indo-Pacific humpback (Sousa chinensis) and Irrawaddy (Orcaella brevirostris) dolphins in Matang waters, Perak, Malaysia

et al. 2022

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“…The derivation of the three-dimensional flow equation for tracer movement in fractures, considering the diffusion effect of the solution and the adsorption effect of the tracer, has achieved excellent results in field applications. This consideration of solution diffusion and tracer adsorption has enhanced the accuracy and effectiveness of tracer flow analysis in fractures . By utilizing a neutron source and a gamma detector, it is possible to identify fracture proppants and determine fracture parameters by comparing the gamma-ray intensity emitted from activated materials in the proppants before and after fracturing.…”

Section: Introductionmentioning

confidence: 99%

“…This consideration of solution diffusion and tracer adsorption has enhanced the accuracy and effectiveness of tracer flow analysis in fractures. 20 By utilizing a neutron source and a gamma detector, it is possible to identify fracture proppants and determine fracture parameters by comparing the gamma-ray intensity emitted from activated materials in the proppants before and after fracturing. This technique allows for the identification of proppants used to support the fractures and the determination of fracture parameters.…”

Section: Introductionmentioning

confidence: 99%

Study on Interpretation Method of Multistage Fracture Tracer Flowback Curve in Tight Oil Reservoirs

Du,

Hao,

et al. 2024

ACS Omega

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Multistage fracturing is widely used in the development of tight oil reservoirs, and the fine description of postfracturing fracture networks is a challenge in tight oil reservoir development. Based on the formation mechanism of dual-wing fractures and the principles of tracer flowback, a mathematical model for tracer concentration in dual-wing fractures is established by considering the convective diffusion of the tracer within the fractures. An interpretation method for tracer flowback curves, utilizing a combination of Gaussian fitting and theoretical equation inversion, is developed to provide a detailed description of fracture parameters such as fracture half-length, fracture width, and fracture conductivity in the postfracturing fracture network. This method can be rapidly applied in field practices. Application examples demonstrate that the relative errors between the calculated cumulative oil and water production using this method and the actual data are less than 5%, validating the accuracy and applicability of the established mathematical model for tracer flowback and the interpretation method for tracer concentration curves in addressing practical problems.

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“…In the Bay of Brunei, whilst Irrawaddy dolphins have been sighted in Brunei waters (Elkin 1992;Gibson-Hill 1950, 1949Jiang et al 2020;Stacey & Letherwood 1997;Weber 1923), much of the literature for the region focuses on the species in Malaysian waters. Past studies on Irrawaddy dolphin in Malaysia side of the bay have been mostly investigated on their distribution, population, abundance, and acoustics (Jaaman et al 2016;Jiang et al 2020Jiang et al , 2019Mahmud 2016;Mahmud et al 2018aMahmud et al , 2018bMuhamad et al 2020Muhamad et al , 2018. Species presence in the bay may be due to favorable environmental conditions.…”

Section: Introductionmentioning

confidence: 99%

Untitled

2021

JSM

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The uniqueness of the Bay of Brunei makes it an ideal place to be inhabited by Irrawaddy dolphins. However, the increasing potential impacts of anthropogenic factors and environmental changes on the dolphins are alarming. The objectives of this study were to determine the seasonal occurrence and distribution, and to estimate the group size of Irrawaddy dolphins in the Bay of Brunei. Surveys were conducted between January 2016 and April 2018. The total distance surveyed was 2,439.2 km in 189.13 h (survey effort = 13,081.93 km.h). Forty-nine groups of Irrawaddy dolphins were recorded with a sighting rate of 0.37 per 100 km.h. Thirteen of the groups were observed with calves. Overall, the group size ranged between 1 and 15 individuals with a mean of 4.5 individuals (SD = 3.3). There was no statistical significance in the number of dolphin sightings between four different monsoon seasons (Northeast, Southwest, April Inter-monsoon, and October Inter-monsoon) (χ 2 = 5.66, df = 3, p > 0.05). The number of sightings and number of individuals suggest that Irrawaddy dolphins are residents of the Bay of Brunei and are in need of a conservation management plan.

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Preliminary analysis of echolocation signals produced by fleeing Irrawaddy dolphins (Orcaella brevirostris)

Cited by 6 publications

References 8 publications

Identifying the hotspot area of Indo-Pacific humpback (Sousa chinensis) and Irrawaddy (Orcaella brevirostris) dolphins in Matang waters, Perak, Malaysia

Identifying the hotspot area of Indo-Pacific humpback (Sousa chinensis) and Irrawaddy (Orcaella brevirostris) dolphins in Matang waters, Perak, Malaysia

Study on Interpretation Method of Multistage Fracture Tracer Flowback Curve in Tight Oil Reservoirs

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