Acoustic Presence of Dolphins through Whistles Detection in Mediterranean Shallow Waters

The evaluation of acoustic temporal rhythms in wide-ranging cetaceans can reveal patterns in animal spatial presence and the occurrence of periodical phenomena. Here, we aimed at assessing the temporal patterns of dolphin’s acoustic presence in a shallow-water area in the Sicily Strait (Mediterranean Sea). Whistles were collected continuously for 14 months from an acoustic monitoring station installed aboard of an elastic seamark. Over a total of 6955 h of recording, 14,048 signals were identified using both automatic and visual methods. Three parameters were analyzed: hourly presence (HP), used as a proxy of the presence of dolphins in the area; detection rate (DR), indicating the acoustic activity rate of dolphins measured per hour in the entire dataset; and detection rate in presence of dolphins (DRD), indicating the acoustic activity rate of dolphins considering only the hours when whistles were recorded. The highest values of both HP and DR were reached during the night, and the Autumn and Winter months, suggesting an increase in the dolphin’s occurrence and a possible moving away and towards the monitoring station potentially following prey. DRD, instead, showed an almost uniform distribution throughout the day implying that when the animals are close to the monitoring station, the acoustic activity does not show any pattern. However, possible changes in the communication exchange along the seasons were suggested. This study complements other work on this subject, improving the knowledge of dolphins’ acoustic activity in the area.

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Simulation study on SAR imaging spectrum of shallow water area using Texel-Marsen-Arsloe spectrum

2013 IEEE International Geoscience and Remote Sensing Symposium - IGARSS ◽

10.1109/igarss.2013.6723032 ◽

2013 ◽

Author(s):

Guoqing Zhou ◽

Tao Yue ◽

Wei Zhao ◽

Xiaodong Tao ◽

Bo Yang ◽

...

Keyword(s):

Shallow Water ◽

Simulation Study ◽

Water Area ◽

Shallow Water Area ◽

Sar Imaging

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Directional Wave Spectra from Video Images Data and SWAN Model

Jurnal Teknologi ◽

10.11113/jt.v74.4651 ◽

2015 ◽

Vol 74 (5) ◽

Author(s):

Muhammad Zikra ◽

Noriaki Hashimoto ◽

Masaru Yamashiro ◽

Kojiro Suzuki

Keyword(s):

Shallow Water ◽

Water Area ◽

Paper Analysis ◽

Wave Spectra ◽

Swan Model ◽

Video Images ◽

Shallow Water Area ◽

Directional Wave ◽

Probe Sensor ◽

Rectification Process

In this paper, analysis of directional wave spectra in shallow water area estimated by video images data has been compared with numerical model of SWAN. Estimation of directional wave spectra from video images is based on the Bayesian Directional Method using a group of pixels brightness on the image. For this study, the pixels can be considered equivalent to fixed instruments as wave probe sensor after rectification process. The results show that there is a good agreement between directional wave spectra estimated by video images data and the SWAN model. Both methods estimate similar shape of directional wave spectra in the shallow water. In addition, the energy distribution of directional wave spectra in shallow water is concentrated significantly in frequency and direction.

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Time variability of acoustic signals in a benign shallow‐water area

The Journal of the Acoustical Society of America ◽

10.1121/1.4743583 ◽

2000 ◽

Vol 108 (5) ◽

pp. 2578-2578

Author(s):

Peter L. Nielsen ◽

Martin Siderius ◽

Finn B. Jensen

Keyword(s):

Shallow Water ◽

Acoustic Signals ◽

Water Area ◽

Time Variability ◽

Shallow Water Area

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Acoustic monitoring of coastal dolphins and their response to naval mine neutralization exercises

Royal Society Open Science ◽

10.1098/rsos.170558 ◽

2017 ◽

Vol 4 (12) ◽

pp. 170558 ◽

Cited By ~ 2

Author(s):

Marc O. Lammers ◽

Marian Howe ◽

Eden Zang ◽

Megan McElligott ◽

Amy Engelhaupt ◽

...

Keyword(s):

Additive Model ◽

Acoustic Monitoring ◽

Acoustic Activity ◽

Virginia Beach ◽

Monitoring Study ◽

Before And After ◽

The Hours ◽

Training Event ◽

Passive Acoustic

To investigate the potential impacts of naval mine neutralization exercises (MINEX) on odontocete cetaceans, a long-term passive acoustic monitoring study was conducted at a US Navy training range near Virginia Beach, USA. Bottom-moored acoustic recorders were deployed in 2012–2016 near the epicentre of MINEX training activity and were refurbished every 2–4 months. Recordings were analysed for the daily presence/absence of dolphins, and dolphin acoustic activity was quantified in detail for the hours and days before and after 31 MINEX training events. Dolphins occurred in the area year-round, but there was clear seasonal variability, with lower presence during winter months. Dolphins exhibited a behavioural response to underwater detonations. Dolphin acoustic activity near the training location was lower during the hours and days following detonations, suggesting that animals left the area and/or reduced their signalling. Concurrent acoustic monitoring farther away from the training area suggested that the radius of response was between 3 and 6 km. A generalized additive model indicated that the predictors that explained the greatest amount of deviance in the data were the day relative to the training event, the hour of the day and circumstances specific to each training event.

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Aromatic hydrocarbons in components of geological environment of the Norwegian and Russian parts of coastal zone of the Barents Sea

10.5194/egusphere-egu2020-7519 ◽

2020 ◽

Author(s):

Anna Kursheva ◽

Inna Morgunova ◽

Vera Petrova ◽

Galina Batova ◽

Ivan Litvinenko ◽

...

Keyword(s):

Molecular Weight ◽

Salt Marshes ◽

Littoral Zone ◽

Barents Sea ◽

Petroleum Products ◽

Water Area ◽

Rocky Shores ◽

Geological Environment ◽

The Barents Sea ◽

Shallow Water Area

Information about hydrocarbons (HCs) distribution in components of geological environment (including aromatic (Ar) compounds) allows to estimate relative amounts of both natural and anthropogenic components and reveal sources of contamination. HCs are widely spread in lithosphere and create stable geochemical background. Variations in their composition attest to the specificity of initial organic matter, conditions of its accumulation and transformation. The studied samples of soils and surface bottom sediments were collected during the research expedition in July, 2019 (supported by RFBR &#8470;18-54-20001 and NFR &#8470;280724). On the Norwegian coast of the Barents Sea the area of study included: salt marshes of Tana and Varanger fjords, littoral zone of rocky shores around Kiberg. In the Russian part of the Barents Sea samples were taken from the shallow water area of the Eastern coast of the Kola Bay. All samples were taken along the sublittoral &#8211; littoral &#8211; supralittoral transects appropriate for a detailed study of the organic matter (OM) spatial distribution. Study of the group composition of ArHCs in the extractable part of soil and sedimentary OM were performed using spectrofluorimetry. &#160;The method is based on the ability of ArHCs to fluoresce under the influence of ultraviolet emitting in narrow spectral ranges determined by their molecular structure. This allows us to characterize the nature of ArHCs and determine possible sources of their input. The spectrum characteristics of samples from intertidal zone of the Tana fjord salt marshes reflect the input of fresh unoxidized petroleum products such as diesel fuels and engine oils. The significant increase of ArHCs fluorescence intensity in surface sediments may testify to recent pollution accidents. The spectrum traditionally associated with the estuarine-delta and lacustrine and swampy facies and characteristic for the post-sedimentation and early diagenetic stage of OM transformation was detected in samples from the salt marshes of Varanger fjord.&#160; ArHCs of mixed origin (natural and anthropogenic) are identified in samples from the littoral zone of rocky shores of Kiberg. The spectral data of littoral sediments are typical for the polluted areas with high input of petroleum products. The specific maxima in the long wavelength region of spectrum that is characteristic for the high molecular weight aromatic compounds from the land plants is also detected in these samples.&#160; Spectral characteristics of ArHCs of bottom sediments and soils collected from the shallow water area of the Russian part of the Barents Sea point to the presence of both low molecular weight benzene HCs (high volatile components of flammable liquids) and high molecular weight compounds (oil fuel, gas oil). The detailed study of these anthropogenic HC components seems to be very important given the fact of their detection in all littoral samples. The further detailed study of the molecular markers and biomarkers (n-alkanes, isoprenoids, cyclanes, terpanes, PAHs) will increase our knowledge about HC sources, efficiency of their microbial and chemical degradation, allow to estimate human impacts on the environment of the region and draw up the regional &#8220;geochemical passport&#8221;.

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Geoacoustic seafloor exploration with a towed array in a shallow water area of the Strait of Sicily

OCEANS 96 MTS/IEEE Conference Proceedings. The Coastal Ocean - Prospects for the 21st Century ◽

10.1109/oceans.1996.572568 ◽

2002 ◽

Author(s):

A. Caiti ◽

S.M. Jesus ◽

A. Kristensen

Keyword(s):

Shallow Water ◽

Water Area ◽

Strait Of Sicily ◽

Shallow Water Area ◽

Towed Array

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SATELLITE-DERIVED BATHYMETRY: ACCURACY ASSESSMENT ON DEPTHS DERIVATION ALGORITHM FOR SHALLOW WATER AREA

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-4-w5-159-2017 ◽

2017 ◽

Vol XLII-4/W5 ◽

pp. 159-164 ◽

Cited By ~ 6

Author(s):

N. M. Said ◽

M. R. Mahmud ◽

R. C. Hasan

Keyword(s):

Shallow Water ◽

Accuracy Assessment ◽

Water Area ◽

Bathymetric Data ◽

Sensing Technology ◽

Shallow Water Area ◽

Multispectral Satellite Imagery ◽

Marginal Improvement ◽

Acquisition Technique ◽

Hydrographic Surveying

Over the years, the acquisition technique of bathymetric data has evolved from a shipborne platform to airborne and presently, utilising space-borne acquisition. The extensive development of remote sensing technology has brought in the new revolution to the hydrographic surveying. Satellite-Derived Bathymetry (SDB), a space-borne acquisition technique which derives bathymetric data from high-resolution multispectral satellite imagery for various purposes recently considered as a new promising technology in the hydrographic surveying industry. Inspiring by this latest developments, a comprehensive study was initiated by National Hydrographic Centre (NHC) and Universiti Teknologi Malaysia (UTM) to analyse SDB as a means for shallow water area acquisition. By adopting additional adjustment in calibration stage, a marginal improvement discovered on the outcomes from both Stumpf and Lyzenga algorithms where the RMSE values for the derived (predicted) depths were 1.432 meters and 1.728 meters respectively. This paper would deliberate in detail the findings from the study especially on the accuracy level and practicality of SDB over the tropical environmental setting in Malaysia.

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WIND AND WAVE RELATIONSHIPS IN A SHALLOW WATER AREA

Coastal Engineering Proceedings ◽

10.9753/icce.v14.6 ◽

1974 ◽

Vol 1 (14) ◽

pp. 6

Author(s):

J.S. Driver ◽

J.D. Pitt

Keyword(s):

Shallow Water ◽

Water Area ◽

Extreme Conditions ◽

Shallow Water Area ◽

Wave Conditions ◽

Direct Measures

An instrumentation system to record direct measures of both wind and wave conditions has been installed at the Wash. Data from these instruments are used in conjunction with long term wind records from another station to predict the frequency and duration of extreme conditions.

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