The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Susan Bengtson Nash - One of the best experts on this subject based on the ideXlab platform.
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lipid and fatty acid profiles of migrating southern hemisphere humpback whales Megaptera novaeangliae
Marine Ecology Progress Series, 2012Co-Authors: Courtney A. Waugh, Michael J Noad, Peter D Nichols, Susan Bengtson NashAbstract:The lipid and fatty acid (FA) composition of the outer blubber layer was characterized in 46 east Australian migrating humpback whales Megaptera novaeangliae. Samples were obtained at 2 time points of the annual migration, which occurs between Antarctic feeding grounds and low-latitude breeding grounds and is associated with a prolonged period of fasting. Blubber lipid composition was dominated by triacylglycerols in all individuals, and the FA profiles of both migration cohorts and sexes were dominated by monounsaturated fatty acids (MUFA). Results indicate that males primarily mobilise polyunsaturated fatty acids in response to migration and fasting, favouring the most readily utilisable FA as governed by their physicochemical properties. In comparison, females appear to initially mobilise short-chain (<18 carbons) MUFA stores, potentially to attend to dependent calves' thermoregulatory needs. Feeding ecology investigations suggested that humpback whales have a species-specific FA composition of their blubber, including a detectable influence of their diet. This study provides the first insight into lipid and FA profiles of Southern Hemisphere humpback whales. A comprehensive understanding of FA dynamics, especially during times of energy deficit, is essential for understanding the nutritional status of Southern Hemisphere humpback whales and thereby the risks posed by growing environmental threats including toxic and persistent lipophilic pollutants.
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Cytochrome P450 isozyme protein verified in the skin of southern hemisphere humpback whales (Megaptera novaeangliae): Implications for biochemical biomarker assessment
Marine Pollution Bulletin, 2011Co-Authors: Courtney A. Waugh, Michael J Noad, Wilhelmina M. Huston, Susan Bengtson NashAbstract:Large mysticete whales represent a unique challenge for chemical risk assessment. Few epidemiological investigations are possible due to the low incidence of adult stranding events. Similarly their often extreme life-history adaptations of prolonged migration and fasting challenge exposure assumptions. Molecular biomarkers offer the potential to complement information yielded through tissue chemical analysis, as well as providing evidence of a molecular response to chemical exposure. In this study we confirm the presence of cytochrome P450 reductase (CPR) and cytochrome P450 isoenzyme 1A1 (CYP1A1) in epidermal tissue of southern hemisphere humpback whales (Megaptera novaeangliae). The detection of CYP1A1 in the integument of the humpback whale affords the opportunity for further quantitative non-destructive investigations of enzyme activity as a function of chemical stress.
Michael J Noad - One of the best experts on this subject based on the ideXlab platform.
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Evidence for the functions of surface-active behaviors in humpback whales (Megaptera novaeangliae)
Marine Mammal Science, 2016Co-Authors: Ailbhe S. Kavanagh, Michael J Noad, Douglas H Cato, Eric Kniest, Kylie Owen, Michael J. Williamson, Simon P. Blomberg, Anne W. Goldizen, Rebecca A DunlopAbstract:As part of their social sound repertoire, migrating humpback whales (Megaptera novaeangliae) perform a large variety of surface-active behaviors, such as breaching and repetitive slapping of the pectoral fins and tail flukes; however, little is known about what factors influence these behaviors and what their functions might be. We investigated the potential functions of surface-active behaviors in humpback whale groups by examining the social and environmental contexts in which they occurred. Focal observations on 94 different groups of whales were collected in conjunction with continuous acoustic monitoring, and data on the social and environmental context of each group. We propose that breaching may play a role in communication between distant groups as the probability of observing this behavior decreased significantly when the nearest whale group was within 4,000 m compared to beyond 4,000 m. Involvement in group interactions, such as the splitting of a group or a group joining with other whales, was an important factor in predicting the occurrence of pectoral, fluke, and peduncle slapping, and we suggest that they play a role in close-range or within-group communication. This study highlights the potentially important and diverse roles of surface-active behaviors in the communication of migrating humpback whales.
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Comparing multiple sampling platforms for measuring the behavior of humpback whales (Megaptera novaeangliae)
Marine Mammal Science, 2015Co-Authors: Elise M. Godwin, Michael J Noad, Eric Kniest, Rebecca A DunlopAbstract:Multiple platform approaches for measuring the behavior of marine mammals may strengthen data quality and quantity. However, if this approach is chosen, reconciliation of behavioral measures between each platform is required. This study compared typical measures of humpback whale (Megaptera novaeangliae) behavior collected from three different sampling platforms; land-based, boat-based, and digital tags (Dtags), to explore similarities and/or discrepancies in data. Visual observations from land-based platforms significantly underestimated group blow rate when compared to boat-based platforms, whereas broad-scale spatial movements (speed and course traveled) were measured similarly by these two platforms. Dtags were used to define dive behavior based on a time and depth criteria, where bouts of short shallow respiration dives (80 s and 10 m) were separated from longer, deeper dives (>80 s and >10 m). At a group level, land and boat platforms agreed on the number of long dives but land platforms missed bouts of short dives. At an individual level, the number of short and long dives observed by boat-based platforms agreed with Dtag recordings. This study highlights the importance of data exploration prior to analyses in multiple platform studies to identify potential discrepancies and appropriately account for any biases.
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Evidence of a Lombard response in migrating humpback whales (Megaptera novaeangliae)
The Journal of the Acoustical Society of America, 2014Co-Authors: Rebecca A Dunlop, Douglas H Cato, Michael J NoadAbstract:The Lombard reflex is an increase in the subject's vocal levels in response to increased noise levels. This functions to maintain an adequate signal-to-noise ratio at the position of the receiver when noise levels vary. While it has been demonstrated in a small number of mammals and birds including some whales, it has not yet been shown to occur in one of the most vocal species of baleen whale, the humpback whale (Megaptera novaeangliae). Humpback whales were simultaneously visually and acoustically tracked (using an array of calibrated hydrophone buoys) as they migrated southward. Source levels of social vocalizations were estimated from measured received levels and a site-specific empirical sound propagation model developed. In total, 226 social vocalizations from 16 passing groups of whales were selected for final analysis. Noise levels were predominantly wind-dependent (from sea surface motion) and ranged from 81 to 108 dB re 1 μPa in the 36 Hz–2.8 kHz band. Vocalization source levels increased by 0.9 dB for every 1 dB increase in wind-dependent background noise levels, with source levels (at 1 m) being maintained ∼60 dB above the noise level.
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lipid and fatty acid profiles of migrating southern hemisphere humpback whales Megaptera novaeangliae
Marine Ecology Progress Series, 2012Co-Authors: Courtney A. Waugh, Michael J Noad, Peter D Nichols, Susan Bengtson NashAbstract:The lipid and fatty acid (FA) composition of the outer blubber layer was characterized in 46 east Australian migrating humpback whales Megaptera novaeangliae. Samples were obtained at 2 time points of the annual migration, which occurs between Antarctic feeding grounds and low-latitude breeding grounds and is associated with a prolonged period of fasting. Blubber lipid composition was dominated by triacylglycerols in all individuals, and the FA profiles of both migration cohorts and sexes were dominated by monounsaturated fatty acids (MUFA). Results indicate that males primarily mobilise polyunsaturated fatty acids in response to migration and fasting, favouring the most readily utilisable FA as governed by their physicochemical properties. In comparison, females appear to initially mobilise short-chain (<18 carbons) MUFA stores, potentially to attend to dependent calves' thermoregulatory needs. Feeding ecology investigations suggested that humpback whales have a species-specific FA composition of their blubber, including a detectable influence of their diet. This study provides the first insight into lipid and FA profiles of Southern Hemisphere humpback whales. A comprehensive understanding of FA dynamics, especially during times of energy deficit, is essential for understanding the nutritional status of Southern Hemisphere humpback whales and thereby the risks posed by growing environmental threats including toxic and persistent lipophilic pollutants.
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Cytochrome P450 isozyme protein verified in the skin of southern hemisphere humpback whales (Megaptera novaeangliae): Implications for biochemical biomarker assessment
Marine Pollution Bulletin, 2011Co-Authors: Courtney A. Waugh, Michael J Noad, Wilhelmina M. Huston, Susan Bengtson NashAbstract:Large mysticete whales represent a unique challenge for chemical risk assessment. Few epidemiological investigations are possible due to the low incidence of adult stranding events. Similarly their often extreme life-history adaptations of prolonged migration and fasting challenge exposure assumptions. Molecular biomarkers offer the potential to complement information yielded through tissue chemical analysis, as well as providing evidence of a molecular response to chemical exposure. In this study we confirm the presence of cytochrome P450 reductase (CPR) and cytochrome P450 isoenzyme 1A1 (CYP1A1) in epidermal tissue of southern hemisphere humpback whales (Megaptera novaeangliae). The detection of CYP1A1 in the integument of the humpback whale affords the opportunity for further quantitative non-destructive investigations of enzyme activity as a function of chemical stress.
Philip S. Hammond - One of the best experts on this subject based on the ideXlab platform.
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Distribution and abundance of West Greenland humpback whales (Megaptera novaeangliae)
Journal of Zoology, 2004Co-Authors: Finn Larsen, Philip S. HammondAbstract:Photo-identification surveys of humpback whales Megaptera novaeangliae were conducted at West Greenland during 1988–93, the last 2 years of which were part of the internationally coordinated humpback whale research programme YoNAH, with the primary aim of estimating abundance for the West Greenland feeding aggregation. The area studied stretched from the coast out to the offshore margin of the banks, determined approximately by the 200 m depth contours, between c. 61°70′N and c. 66°N. The surveys were conducted between early July and mid-August and 993 h were expended on searching effort. A total of 670 groups of humpback whales was encountered leading to the identification of 348 individual animals. Three areas of concentration were identified: an area off Nuuk; an area at c. 63°30′N; and an area off Frederikshab. Sequential Petersen capture–recapture estimates of abundance were calculated for five pairs of years at 357 (1988–89), 355 (1989–90), 566 (1990–91), 376 (1991–92), and 348 (1992–93). Excluding the anomalously high estimate in 1990–91, the simple mean is 359 (se= 27.3, CV = 0.076) and the inverse CV-squared weighted mean is 356 animals (se= 24.9, CV = 0.070). These calculations lead us to conclude that between 1988 and 1993 there were 360 humpbacks (CV = 0.07) in the West Greenland feeding aggregation. Using the Cormack–Jolly–Seber model framework non-calf survival rate was estimated at 0.957 (se= 0.028). Our data have low power (P < 0.3) to detect a trend of 3.1%, assuming the probability of a type I error was 0.05.
Courtney A. Waugh - One of the best experts on this subject based on the ideXlab platform.
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lipid and fatty acid profiles of migrating southern hemisphere humpback whales Megaptera novaeangliae
Marine Ecology Progress Series, 2012Co-Authors: Courtney A. Waugh, Michael J Noad, Peter D Nichols, Susan Bengtson NashAbstract:The lipid and fatty acid (FA) composition of the outer blubber layer was characterized in 46 east Australian migrating humpback whales Megaptera novaeangliae. Samples were obtained at 2 time points of the annual migration, which occurs between Antarctic feeding grounds and low-latitude breeding grounds and is associated with a prolonged period of fasting. Blubber lipid composition was dominated by triacylglycerols in all individuals, and the FA profiles of both migration cohorts and sexes were dominated by monounsaturated fatty acids (MUFA). Results indicate that males primarily mobilise polyunsaturated fatty acids in response to migration and fasting, favouring the most readily utilisable FA as governed by their physicochemical properties. In comparison, females appear to initially mobilise short-chain (<18 carbons) MUFA stores, potentially to attend to dependent calves' thermoregulatory needs. Feeding ecology investigations suggested that humpback whales have a species-specific FA composition of their blubber, including a detectable influence of their diet. This study provides the first insight into lipid and FA profiles of Southern Hemisphere humpback whales. A comprehensive understanding of FA dynamics, especially during times of energy deficit, is essential for understanding the nutritional status of Southern Hemisphere humpback whales and thereby the risks posed by growing environmental threats including toxic and persistent lipophilic pollutants.
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Cytochrome P450 isozyme protein verified in the skin of southern hemisphere humpback whales (Megaptera novaeangliae): Implications for biochemical biomarker assessment
Marine Pollution Bulletin, 2011Co-Authors: Courtney A. Waugh, Michael J Noad, Wilhelmina M. Huston, Susan Bengtson NashAbstract:Large mysticete whales represent a unique challenge for chemical risk assessment. Few epidemiological investigations are possible due to the low incidence of adult stranding events. Similarly their often extreme life-history adaptations of prolonged migration and fasting challenge exposure assumptions. Molecular biomarkers offer the potential to complement information yielded through tissue chemical analysis, as well as providing evidence of a molecular response to chemical exposure. In this study we confirm the presence of cytochrome P450 reductase (CPR) and cytochrome P450 isoenzyme 1A1 (CYP1A1) in epidermal tissue of southern hemisphere humpback whales (Megaptera novaeangliae). The detection of CYP1A1 in the integument of the humpback whale affords the opportunity for further quantitative non-destructive investigations of enzyme activity as a function of chemical stress.
Finn Larsen - One of the best experts on this subject based on the ideXlab platform.
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Distribution and abundance of West Greenland humpback whales (Megaptera novaeangliae)
Journal of Zoology, 2004Co-Authors: Finn Larsen, Philip S. HammondAbstract:Photo-identification surveys of humpback whales Megaptera novaeangliae were conducted at West Greenland during 1988–93, the last 2 years of which were part of the internationally coordinated humpback whale research programme YoNAH, with the primary aim of estimating abundance for the West Greenland feeding aggregation. The area studied stretched from the coast out to the offshore margin of the banks, determined approximately by the 200 m depth contours, between c. 61°70′N and c. 66°N. The surveys were conducted between early July and mid-August and 993 h were expended on searching effort. A total of 670 groups of humpback whales was encountered leading to the identification of 348 individual animals. Three areas of concentration were identified: an area off Nuuk; an area at c. 63°30′N; and an area off Frederikshab. Sequential Petersen capture–recapture estimates of abundance were calculated for five pairs of years at 357 (1988–89), 355 (1989–90), 566 (1990–91), 376 (1991–92), and 348 (1992–93). Excluding the anomalously high estimate in 1990–91, the simple mean is 359 (se= 27.3, CV = 0.076) and the inverse CV-squared weighted mean is 356 animals (se= 24.9, CV = 0.070). These calculations lead us to conclude that between 1988 and 1993 there were 360 humpbacks (CV = 0.07) in the West Greenland feeding aggregation. Using the Cormack–Jolly–Seber model framework non-calf survival rate was estimated at 0.957 (se= 0.028). Our data have low power (P < 0.3) to detect a trend of 3.1%, assuming the probability of a type I error was 0.05.