The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Peter T Madsen - One of the best experts on this subject based on the ideXlab platform.
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basin wide contributions to the underwater soundscape by multiple seismic surveys with implications for Marine Mammals in baffin bay greenland
Marine Pollution Bulletin, 2019Co-Authors: Line A Kyhn, Jakob Tougaard, Danuta M Wisniewska, Kristian Beedholm, Malene Simon, Anders Mosbech, Peter T MadsenAbstract:Abstract Seismic surveys increasingly operate in deeper Arctic waters with propagation conditions and Marine mammal fauna different from the better-studied temperate, or shallow-water, regions. Using 31 calibrated sound recorders, we quantified noise contributions from four concurrent seismic surveys in Baffin Bay, Greenland, to estimate their potential impacts on Marine Mammals. The impact was cumulative as the noise level rose in response to the onset of each survey: on a minute-by-minute scale the sound-exposure-levels varied by up to 70 dB (20 dB on average), depending on range to the seismic vessel, local bathymetry effects and interference patterns, representing a significant change in the auditory scene for Marine Mammals. Airgun pulse energy did not decrease to ambient before arrival of the next pulse leaving very little low-frequency masking-free time. Overall, the measured values matched well with pre-season-modeling, emphasizing the importance of noise-modeling in impact assessments, if responses of focal Marine Mammals are known.
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wind turbine underwater noise and Marine Mammals implications of current knowledge and data needs
Marine Ecology Progress Series, 2006Co-Authors: Peter T Madsen, Klaus Lucke, Magnus Wahlberg, Jakob Tougaard, Peter L TyackAbstract:The demand for renewable energy has led to construction of offshore wind farms with high-power turbines, and many more wind farms are being planned for the shallow waters of the world's Marine habitats. The growth of offshore wind farms has raised concerns about their impact on the Marine environment. Marine Mammals use sound for foraging, orientation and communication and are therefore possibly susceptible to negative effects of man-made noise generated from con- structing and operating large offshore wind turbines. This paper reviews the existing literature and assesses zones of impact from different noise-generating activities in conjunction with wind farms on 4 representative shallow-water species of Marine Mammals. Construction involves many types of activities that can generate high sound pressure levels, and pile-driving seems to be the noisiest of all. Both the literature and modeling show that pile-driving and other activities that generate intense impulses during construction are likely to disrupt the behavior of Marine Mammals at ranges of many kilometers, and that these activities have the potential to induce hearing impairment at close range. The reported noise levels from operating wind turbines are low, and are unlikely to impair hearing in Marine Mammals. The impact zones for Marine Mammals from operating wind turbines depend on the low-frequency hearing-abilities of the species in question, on sound-propagation conditions, and on the presence of other noise sources such as shipping. The noise impact on Marine Mammals is more severe during the construction of wind farms than during their operation.
O C H Kwok - One of the best experts on this subject based on the ideXlab platform.
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recent epidemiologic and clinical importance of toxoplasma gondii infections in Marine Mammals 2009 2020
Veterinary Parasitology, 2020Co-Authors: J P Dubey, F H A Murata, Camila K Cerqueiracezar, O C H Kwok, Michael E GriggAbstract:Toxoplasma gondii infections are common in humans and animals worldwide. T. gondii causes mortality in several species of Marine Mammals, including threatened Southern sea otters (Enhydra lutris) and endangered Hawaiian monk seals (Monachus schauinslandi). Marine Mammals are now considered sentinels for environmental exposure to protozoan agents contaminating Marine waters, including T. gondii oocysts. Marine Mammals also serve as food for humans and can result in foodborne T. gondii infections in humans. The present review summarizes worldwide information on the prevalence of clinical and subclinical infections, epidemiology, and genetic diversity of T. gondii infecting Marine Mammals in the past decade. The role of genetic types of T. gondii and clinical disease is discussed.
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toxoplasma gondii neospora caninum sarcocystis neurona and sarcocystis canis like infections in Marine Mammals
Veterinary Parasitology, 2003Co-Authors: J P Dubey, R Zarnke, Nancy J Thomas, S K Wong, W Van Bonn, M Briggs, J W Davis, R Ewing, M Mense, O C H KwokAbstract:Toxoplasma gondii, Neospora caninum, Sarcocystis neurona, and S. canis are related protozoans that can cause mortality in many species of domestic and wild animals. Recently, T. gondii and S. neurona were recognized to cause encephalitis in Marine Mammals. As yet, there is no report of natural exposure of N. caninum in Marine Mammals. In the present study, antibodies to T. gondii and N. caninum were assayed in sera of several species of Marine Mammals. For T. gondii, sera were diluted 1:25, 1:50, and 1:500 and assayed in the T. gondii modified agglutination test (MAT). Antibodies (MAT ≥1:25) to T. gondii were found in 89 of 115 (77%) dead, and 18 of 30 (60%) apparently healthy sea otters (Enhydra lutris), 51 of 311 (16%) Pacific harbor seals ( Phoca vitulina), 19 of 45 (42%) sea lions (Zalophus californianus), 5 of 32 (16%) ringed seals (Phoca hispida ), 4o f
J P Dubey - One of the best experts on this subject based on the ideXlab platform.
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recent epidemiologic and clinical importance of toxoplasma gondii infections in Marine Mammals 2009 2020
Veterinary Parasitology, 2020Co-Authors: J P Dubey, F H A Murata, Camila K Cerqueiracezar, O C H Kwok, Michael E GriggAbstract:Toxoplasma gondii infections are common in humans and animals worldwide. T. gondii causes mortality in several species of Marine Mammals, including threatened Southern sea otters (Enhydra lutris) and endangered Hawaiian monk seals (Monachus schauinslandi). Marine Mammals are now considered sentinels for environmental exposure to protozoan agents contaminating Marine waters, including T. gondii oocysts. Marine Mammals also serve as food for humans and can result in foodborne T. gondii infections in humans. The present review summarizes worldwide information on the prevalence of clinical and subclinical infections, epidemiology, and genetic diversity of T. gondii infecting Marine Mammals in the past decade. The role of genetic types of T. gondii and clinical disease is discussed.
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toxoplasma gondii neospora caninum sarcocystis neurona and sarcocystis canis like infections in Marine Mammals
Veterinary Parasitology, 2003Co-Authors: J P Dubey, R Zarnke, Nancy J Thomas, S K Wong, W Van Bonn, M Briggs, J W Davis, R Ewing, M Mense, O C H KwokAbstract:Toxoplasma gondii, Neospora caninum, Sarcocystis neurona, and S. canis are related protozoans that can cause mortality in many species of domestic and wild animals. Recently, T. gondii and S. neurona were recognized to cause encephalitis in Marine Mammals. As yet, there is no report of natural exposure of N. caninum in Marine Mammals. In the present study, antibodies to T. gondii and N. caninum were assayed in sera of several species of Marine Mammals. For T. gondii, sera were diluted 1:25, 1:50, and 1:500 and assayed in the T. gondii modified agglutination test (MAT). Antibodies (MAT ≥1:25) to T. gondii were found in 89 of 115 (77%) dead, and 18 of 30 (60%) apparently healthy sea otters (Enhydra lutris), 51 of 311 (16%) Pacific harbor seals ( Phoca vitulina), 19 of 45 (42%) sea lions (Zalophus californianus), 5 of 32 (16%) ringed seals (Phoca hispida ), 4o f
Kenneth M Y Leung - One of the best experts on this subject based on the ideXlab platform.
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occurrence and trophic magnification profile of triphenyltin compounds in Marine Mammals and their corresponding food webs
Environment International, 2020Co-Authors: Ronia Chungtin Sham, Lily S R Tao, Yanny K Y Mak, Jason K C Yau, Tak Cheung Wai, Guangjie Zhou, Xinhong Wang, Kenneth M Y LeungAbstract:Abstract The occurrence of triphenyltin (TPT) compounds, a highly toxic antifouling biocide, has been documented in Marine environments and organisms all over the world. While some studies showed that Marine Mammals can be used as sentinel organisms to evaluate the pollution status of emerging contaminants in the environment because of their long lifespans and high trophic levels, information regarding the contamination status of TPT in Marine mammal species has been limited over the past decade. More importantly, the primary bioaccumulation pathway of TPT in these long-lived apex predators and the corresponding Marine food web is still uncertain. Therefore, this study aimed to evaluate the contamination statuses of TPT in two Marine mammal species, namely the finless porpoise and the Indo-Pacific humpback dolphin, and assess the trophic magnification potential of TPT along the food webs of these two species, using stable isotope analysis, and chemical analysis with gas chromatography-mass spectrometry. The results showed that TPT is the predominant residue in majority of the analyzed individuals of two Marine Mammals, with concentrations ranging from 426.2 to 3476.6 ng/g wet weight in their muscle tissues. Our results also demonstrated an exponential increase in the concentration of TPT along the Marine food web, indicating that trophic magnification occurs in the respective food webs of the two Marine Mammals. The range of trophic magnification factors of TPT in the food webs of finless porpoise and Indo-Pacific humpback dolphin was 2.51–3.47 and 2.45–3.39, respectively. These results suggest that high trophic organisms may be more vulnerable to the exposure of TPT-contaminated environments due to the high trophic magnification potential, and thus ecological risk of these compounds ought to be assessed with the consideration of their bioaccumulation potentials in these Marine Mammals.
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tracking dietary sources of short and medium chain chlorinated paraffins in Marine Mammals through a subtropical Marine food web
Environmental Science & Technology, 2017Co-Authors: Lixi Zeng, Kenneth M Y Leung, James Lam, Hui Chen, Paul K S LamAbstract:Our previous study revealed an elevated accumulation of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in Marine Mammals from Hong Kong waters in the South China Sea. To examine the bioaccumulation potential and biomagnification in these apex predators, we sampled the dietary items of Marine Mammals and tracked the sources of SCCPs and MCCPs through a Marine food web in this region. Sixteen fish species, seven crustacean species, and four mollusk species were collected, and the main prey species were identified for two species of Marine Mammals. Concentrations of ∑SCCPs and ∑MCCPs in these collected species suggested a moderate pollution level in Hong Kong waters compared to the global range. Lipid content was found to mediate congener-specific bioaccumulation in these Marine species. Significantly positive correlations were observed between trophic levels and concentrations of ∑SCCPs or ∑MCCPs (p < 0.05). Trophic magnification factors for ∑SCCPs and ∑MCCPs were 4...
Peter L Tyack - One of the best experts on this subject based on the ideXlab platform.
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implications for Marine Mammals of large scale changes in the Marine acoustic environment
Journal of Mammalogy, 2008Co-Authors: Peter L TyackAbstract:The amount of underwater sound from ship traffic, commercial, research, and military sound sources has increased significantly over the past century. Marine Mammals and many other Marine animals rely on sound for short- and long-range communication, for orientation, and for locating prey. This reliance has raised concern that elevated sound levels from human sources may interfere with the behavior and physiology of Marine animals. The dominant source of human sound in the sea stems from propulsion of ships. Shipping noise centers in the 20to 200-Hz band. Frequencies this low propagate efficiently in the sea, and shipping has elevated the global deepwater ambient noise 10- to 100-fold in this frequency band. Baleen whales use the same frequency band for some of their communication signals, and concern has been raised that elevated ambient noise may reduce the range over which they can communicate. Marine Mammals have a variety of mechanisms to compensate for increased noise, but little is known about the maximum range at which they may need to communicate. Some of the most intense human sources of sound include air guns used for seismic exploration and sonar for military and commercial use. Human sources of sound in the ocean can disturb Marine Mammals, evoking behavioral responses that can productively be viewed as similar to predation risk, and they can trigger allostatic physiological responses to adapt to the stressor. Marine Mammals have been shown to avoid some human sound sources at ranges of kilometers, raising concern about displacement from important habitats. There are few studies to guide predictions of when such changes start to lower the fitness of individuals or have negative consequences for the population. Although acute responses to intense sounds have generated considerable interest, the more significant risk to populations of Marine Mammals is likely to stem from less visible effects of chronic exposure.
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wind turbine underwater noise and Marine Mammals implications of current knowledge and data needs
Marine Ecology Progress Series, 2006Co-Authors: Peter T Madsen, Klaus Lucke, Magnus Wahlberg, Jakob Tougaard, Peter L TyackAbstract:The demand for renewable energy has led to construction of offshore wind farms with high-power turbines, and many more wind farms are being planned for the shallow waters of the world's Marine habitats. The growth of offshore wind farms has raised concerns about their impact on the Marine environment. Marine Mammals use sound for foraging, orientation and communication and are therefore possibly susceptible to negative effects of man-made noise generated from con- structing and operating large offshore wind turbines. This paper reviews the existing literature and assesses zones of impact from different noise-generating activities in conjunction with wind farms on 4 representative shallow-water species of Marine Mammals. Construction involves many types of activities that can generate high sound pressure levels, and pile-driving seems to be the noisiest of all. Both the literature and modeling show that pile-driving and other activities that generate intense impulses during construction are likely to disrupt the behavior of Marine Mammals at ranges of many kilometers, and that these activities have the potential to induce hearing impairment at close range. The reported noise levels from operating wind turbines are low, and are unlikely to impair hearing in Marine Mammals. The impact zones for Marine Mammals from operating wind turbines depend on the low-frequency hearing-abilities of the species in question, on sound-propagation conditions, and on the presence of other noise sources such as shipping. The noise impact on Marine Mammals is more severe during the construction of wind farms than during their operation.
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a digital acoustic recording tag for measuring the response of wild Marine Mammals to sound
IEEE Journal of Oceanic Engineering, 2003Co-Authors: Mark P Johnson, Peter L TyackAbstract:Definitive studies on the response of Marine Mammals to anthropogenic sound are hampered by the short surface time and deep-diving lifestyle of many species. A novel archival tag, called the DTAG, has been developed to monitor the behavior of Marine Mammals, and their response to sound, continuously throughout the dive cycle. The tag contains a large array of solid-state memory and records continuously from a built-in hydrophone and suite of sensors. The sensors sample the orientation of the animal in three dimensions with sufficient speed and resolution to capture individual fluke strokes. Audio and sensor recording is synchronous so the relative timing of sounds and motion can be determined precisely. The DTAG has been attached to more than 30 northern right whales (Eubalaena glacialis) and 20 sperm whales (Physeter macrocephalus) with recording duration of up to 12 h per deployment. Several deployments have included sound playbacks to the tagged whale and a transient response to at least one playback is evident in the tag data.
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a digital acoustic recording tag for measuring the response of Marine Mammals to sound
Journal of the Acoustical Society of America, 2000Co-Authors: Mark A Johnson, Peter L Tyack, Douglas P Nowacek, Alex ShorterAbstract:There is growing concern about the effect on Marine Mammals of underwater sound sources such as vessels, industrial equipment, and sonar. In order to quantify the reaction of these animals to sound, controlled exposure experiments have been attempted using surface observations or vocal monitoring to estimate response. However, the short surface time of most Marine Mammals, and their often unknown vocalization rates, limit the effectiveness of such experiments. To address these problems, a small digital recording tag, the DTAG, has been developed capable of simultaneously sampling the acoustic environment of the host animal, together with its orientation, heading, and depth. The tag has a 400‐Mbyte memory array sufficient to record audio and sensor signals for several hours. The tag is encapsulated in a plastic resin and can operate at a water depth up to 3000 m. Programing and data off‐load are accomplished with an infrared communications link to a personal computer. The DTAG has been deployed on northern right whales and sperm whales using suction cup attachments. Delivery was by means of a cantilevered pole from a small boat. The resulting data indicate a number of behavioral response metrics as well as new results on dive behavior and vocalization rates.
