The Experts below are selected from a list of 525 Experts worldwide ranked by ideXlab platform
Kristin L Laidre - One of the best experts on this subject based on the ideXlab platform.
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highly directional sonar beam of Narwhals monodon monoceros measured with a vertical 16 hydrophone array
PLOS ONE, 2016Co-Authors: Jens C Koblitz, Peter Stilz, Marianne H Rasmussen, Kristin L LaidreAbstract:Recordings of Narwhal (Monodon monoceros) echolocation signals were made using a linear 16 hydrophone array in the pack ice of Baffin Bay, West Greenland in 2013 at eleven sites. An average -3 dB beam width of 5.0° makes the Narwhal click the most directional biosonar signal reported for any species to date. The beam shows a dorsal-ventral asymmetry with a narrower beam above the beam axis. This may be an evolutionary advantage for toothed whales to reduce echoes from the water surface or sea ice surface. Source level measurements show Narwhal click intensities of up to 222 dB pp re 1 μPa, with a mean apparent source level of 215 dB pp re 1 μPa. During ascents and descents the Narwhals perform scanning in the vertical plane with their sonar beam. This study provides valuable information for reference sonar parameters of Narwhals and for the use of acoustic monitoring in the Arctic.
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use of glacial fronts by Narwhals monodon monoceros in west greenland
Biology Letters, 2016Co-Authors: Kristin L Laidre, Mads Peter Heidejorgensen, Rune Dietz, Twila Moon, Donna D W Hauser, Richard Mcgovern, Ben HudsonAbstract:Glacial fronts are important summer habitat for Narwhals (Monodon monoceros); however, no studies have quantified which glacial properties attract whales. We investigated the importance of glacial ...
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Polar Biol (2008) 31:1295–1306 DOI 10.1007/s00300-008-0466-4ORIGINAL PAPER Movements of Narwhals (Monodon monoceros) from Admiralty Inlet monitored by satellite telemetry
2016Co-Authors: Rune Dietz, Kristin L Laidre, Jack Orr, Pierre Richard, Mads Peter Heide-jørgensen, H C SchmidtAbstract:in Admiralty Inlet showed a diVerent summer distributional pattern than previous Narwhal-tracking studies from Somer-set Island, Eclipse Sound and Melville Bay. The migration of the Narwhals tracked from Admiralty Inlet moved out through Lancaster Sound 15 days earlier (P < 0.0001) than the Narwhals summering around Eclipse Sound, whereas the Admiralty Inlet Narwhals reached the mouths of Eclipse Sound 18 days later (P < 0.0001) than the Eclipse Sound summering population. The winter range of the Admiralty Inlet Narwhals overlapped with the winter range of narwh-als from Melville Bay and Eclipse Sound in central south-ern BaYn Bay and Northern Davis Strait, but not with the winter range of Narwhals from Somerset Island that win-tered further north. Distribution size of range, and popula-tion size did not appear to be related. An example of considerable year to year variation between area of summer and winter distribution in the 2 years was believed to be related to the sample size and number of pods of whales tagged, rather than to diVerences in sex or age classes
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Sonar parameters of 11 on-axis Narwhal clicks.
2016Co-Authors: Jens C Koblitz, Peter Stilz, Marianne H Rasmussen, Kristin L LaidreAbstract:Sonar parameters of 11 on-axis Narwhal clicks.
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behavioral ecology of Narwhals in a changing arctic
2014Co-Authors: Kristin L Laidre, Mads P Heidejoergensen, Harry Stern, Marianne H Rasmussen, Mikkel Villum JensenAbstract:Abstract : Our primary goal is to understand baseline Narwhal (Monodon monoceros) behavioral ecology in the pack ice of Baffin Bay. We will collect data on the species acoustic, movement, and diving ecology in the offshore pack ice of Baffin Bay over a 4 year long research program with three ecological focus areas (acoustic ecology, sea ice ecology, and foraging ecology). Our longitudinal and cross-population analyses will use a suite of ecological modeling approaches over a 2 decade period that encompass a period of sea ice decline and increased anthropogenic activities in West Greenland (1993-present).
Mads Peter Heidejorgensen - One of the best experts on this subject based on the ideXlab platform.
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paradoxical escape responses by Narwhals monodon monoceros
Science, 2017Co-Authors: Terrie M Williams, Susanna B Blackwell, Beau Richter, Mikkelholger S Sinding, Mads Peter HeidejorgensenAbstract:Until recent declines in Arctic sea ice levels, Narwhals ( Monodon monoceros ) have lived in relative isolation from human perturbation and sustained predation pressures. The resulting naivety has made this cryptic, deep-diving cetacean highly susceptible to disturbance, although quantifiable effects have been lacking. We deployed a submersible, animal-borne electrocardiograph-accelerometer-depth recorder to monitor physiological and behavioral responses of East Greenland Narwhals after release from net entanglement and stranding. Escaping Narwhals displayed a paradoxical cardiovascular down-regulation (extreme bradycardia with heart rate ≤4 beats per minute) superimposed on exercise up-regulation (stroke frequency >25 strokes per minute and energetic costs three to six times the resting rate of energy expenditure) that rapidly depleted onboard oxygen stores. We attribute this unusual reaction to opposing cardiovascular signals—from diving, exercise, and neurocognitive fear responses—that challenge physiological homeostasis.
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use of glacial fronts by Narwhals monodon monoceros in west greenland
Biology Letters, 2016Co-Authors: Kristin L Laidre, Mads Peter Heidejorgensen, Rune Dietz, Twila Moon, Donna D W Hauser, Richard Mcgovern, Ben HudsonAbstract:Glacial fronts are important summer habitat for Narwhals (Monodon monoceros); however, no studies have quantified which glacial properties attract whales. We investigated the importance of glacial ...
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size and trends of the bowhead whale beluga and Narwhal stocks wintering off west greenland
Nammco Scientific Publications, 2014Co-Authors: Mads Peter Heidejorgensen, Mario AcquaroneAbstract:To assess the size and trends of the abundance of the bowhead whale ( Balaena mysticetus ), the beluga, or white whale ( Delphinapterus leucas ), and the Narwhal ( Monodon monoceros ) visual aerial surveys were conducted in West Greenland in March 1998 and 1999. An estimated 49 bowhead whales (95% CI: 13 to 188) were present at the surface in 1998. Data from land-based observations enabled correction for bowhead whales that were not available at the surface to be seen during the survey. By applying a rounded average of 80% (SE=3) for submergence an estimate of 246 bowhead whales (95% CI: 62 to 978) in 1998 was obtained. The 76 and 47 sightings of beluga pods in 1998 and 1999, respectively, had distributions similar to those of previous surveys with the highest concentration at the northern edge of the northern part of Store Hellefiskebanke. No belugas were seen in the southernmost area between Maniitsoq and Paamiut. The index estimate of the abundance of belugas comparable with previous surveys was 929 (95% CI: 563 to 1,533) in 1998 and 735 (95% CI: 436 to 1,239) in 1999. When analysing the sightings as a line-transect survey and correcting for whales that were either submerged or at the surface but missed by the observers an estimated 7,941 (95% CI: 3,650 to 17,278) belugas wintered in West Greenland in 1998-1999. The uncorrected estimate of Narwhal abundance was 524 (95% CI: 214 to 1,284) and correcting for the same biases as for the belugas gives a total abundance of 2,861 (95% CI: 954 to 8,578) Narwhals in 1998-1999.
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movements of Narwhals monodon monoceros from admiralty inlet monitored by satellite telemetry
Polar Biology, 2008Co-Authors: Rune Dietz, Mads Peter Heidejorgensen, Kristin L Laidre, Jack Orr, Pierre Richard, H C SchmidtAbstract:Twenty-one Narwhals tagged in 2003 and 2004 in Admiralty Inlet showed a different summer distributional pattern than previous Narwhal-tracking studies from Somerset Island, Eclipse Sound and Melville Bay. The migration of the Narwhals tracked from Admiralty Inlet moved out through Lancaster Sound 15 days earlier (P < 0.0001) than the Narwhals summering around Eclipse Sound, whereas the Admiralty Inlet Narwhals reached the mouths of Eclipse Sound 18 days later (P < 0.0001) than the Eclipse Sound summering population. The winter range of the Admiralty Inlet Narwhals overlapped with the winter range of Narwhals from Melville Bay and Eclipse Sound in central southern Baffin Bay and Northern Davis Strait, but not with the winter range of Narwhals from Somerset Island that wintered further north. Distribution size of range, and population size did not appear to be related. An example of considerable year to year variation between area of summer and winter distribution in the 2 years was believed to be related to the sample size and number of pods of whales tagged, rather than to differences in sex or age classes.
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age specific growth and remarkable longevity in Narwhals monodon monoceros from west greenland as estimated by aspartic acid racemization
Journal of Mammalogy, 2007Co-Authors: Eva Garde, Mads Peter Heidejorgensen, Steen Honore Hansen, Gosta Nachman, Mads C ForchhammerAbstract:Abstract Eyes from 75 Narwhals (Monodon monoceros) were collected in West Greenland in 1993 and 2004 for the purpose of age estimation. Age estimates were based on the racemization of l-aspartic acid to d-aspartic acid in the nucleus of the eye lens. The ratio of d- and l-enantiomers was measured using high-performance liquid chromatography. The aspartic acid racemization rate (kAsp) was estimated to be 0.001045/year ± 0.000069 SE by regression of d/l ratios on age estimated by length from 15 young Narwhals (≤298 cm) and by earplug laminations from 13 fin whales (Balaenoptera physalus). The d/l ratio at age 0 ((d/l)0) was estimated to be 0.0288 by regression of d/l ratios against the estimated age of the 15 young Narwhals. The intercept of the regression slope, providing twice the (d/l)0 value, was 0.05759 ± 0.00147 SE. The maximum estimated age was a 115-year-old (±10 SE) female. Asymptotic body length was estimated to be 396 cm for females and 457 cm for males, and asymptotic body mass was estimated to ...
Rune Dietz - One of the best experts on this subject based on the ideXlab platform.
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mercury and neurochemical biomarkers in multiple brain regions of five arctic marine mammals
Neurotoxicology, 2021Co-Authors: J P Desforges, Christian Sonne, Rune Dietz, Bjarni Mikkelsen, Maria Dam, Frank F Riget, Signe Sveegaard, Niladri BasuAbstract:Abstract Mercury is a neurotoxic chemical that represents one of the greatest pollution threats to Arctic ecosystem health. Evaluating the direct neurotoxic effects of mercury in free ranging wildlife is challenging, necessitating the use of neurochemical biomarkers to assess potential sub-clinical neurological changes. The objective of this study was to characterize the distribution and speciation of mercury, as well as exposure-associated changes in neurochemistry, across multiple brain regions (n = 10) and marine mammal species (n = 5) that each occupy a trophic niche in the Arctic ecosystem. We found consistent species differences in mean brain and brain region-specific concentrations of total mercury (THg) and methyl mercury (MeHg), with higher concentrations in toothed whales (Narwhal, pilot whales and harbour porpoise) compared to fur-bearing mammals (polar bear and ringed seal). Mean THg (μg/g dw) in decreasing rank order was: pilot whale (11.9) > Narwhal (7.7) > harbour porpoise (3.6) > polar bear (0.6) > ringed seal (0.2). The higher THg concentrations in toothed whales was associated with a marked reduction in the percentage of MeHg ( 70 %) that had lower brain THg concentrations. This pattern in mercury concentration and speciation corresponded broadly to an overall higher number of mercury-associated neurochemical biomarker correlations in toothed whales. Of the 226 correlations between mercury and neurochemical biomarkers across brain regions, we found 60 (27 %) meaningful relationships (r>0.60 or p
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use of glacial fronts by Narwhals monodon monoceros in west greenland
Biology Letters, 2016Co-Authors: Kristin L Laidre, Mads Peter Heidejorgensen, Rune Dietz, Twila Moon, Donna D W Hauser, Richard Mcgovern, Ben HudsonAbstract:Glacial fronts are important summer habitat for Narwhals (Monodon monoceros); however, no studies have quantified which glacial properties attract whales. We investigated the importance of glacial ...
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Polar Biol (2008) 31:1295–1306 DOI 10.1007/s00300-008-0466-4ORIGINAL PAPER Movements of Narwhals (Monodon monoceros) from Admiralty Inlet monitored by satellite telemetry
2016Co-Authors: Rune Dietz, Kristin L Laidre, Jack Orr, Pierre Richard, Mads Peter Heide-jørgensen, H C SchmidtAbstract:in Admiralty Inlet showed a diVerent summer distributional pattern than previous Narwhal-tracking studies from Somer-set Island, Eclipse Sound and Melville Bay. The migration of the Narwhals tracked from Admiralty Inlet moved out through Lancaster Sound 15 days earlier (P < 0.0001) than the Narwhals summering around Eclipse Sound, whereas the Admiralty Inlet Narwhals reached the mouths of Eclipse Sound 18 days later (P < 0.0001) than the Eclipse Sound summering population. The winter range of the Admiralty Inlet Narwhals overlapped with the winter range of narwh-als from Melville Bay and Eclipse Sound in central south-ern BaYn Bay and Northern Davis Strait, but not with the winter range of Narwhals from Somerset Island that win-tered further north. Distribution size of range, and popula-tion size did not appear to be related. An example of considerable year to year variation between area of summer and winter distribution in the 2 years was believed to be related to the sample size and number of pods of whales tagged, rather than to diVerences in sex or age classes
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movements of Narwhals monodon monoceros from admiralty inlet monitored by satellite telemetry
Polar Biology, 2008Co-Authors: Rune Dietz, Mads Peter Heidejorgensen, Kristin L Laidre, Jack Orr, Pierre Richard, H C SchmidtAbstract:Twenty-one Narwhals tagged in 2003 and 2004 in Admiralty Inlet showed a different summer distributional pattern than previous Narwhal-tracking studies from Somerset Island, Eclipse Sound and Melville Bay. The migration of the Narwhals tracked from Admiralty Inlet moved out through Lancaster Sound 15 days earlier (P < 0.0001) than the Narwhals summering around Eclipse Sound, whereas the Admiralty Inlet Narwhals reached the mouths of Eclipse Sound 18 days later (P < 0.0001) than the Eclipse Sound summering population. The winter range of the Admiralty Inlet Narwhals overlapped with the winter range of Narwhals from Melville Bay and Eclipse Sound in central southern Baffin Bay and Northern Davis Strait, but not with the winter range of Narwhals from Somerset Island that wintered further north. Distribution size of range, and population size did not appear to be related. An example of considerable year to year variation between area of summer and winter distribution in the 2 years was believed to be related to the sample size and number of pods of whales tagged, rather than to differences in sex or age classes.
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surfacing times and dive rates for Narwhals monodon monoceros and belugas delphinapterus leucas
Arctic, 2001Co-Authors: Mads Peter Heidejorgensen, N Hammeken, Rune Dietz, Jack Orr, P R RichardAbstract:Time spent at and near the sea surface was measured for 25 Narwhals, Monodon monoceros, and 39 belugas or white whales, Delphinapterus leucas, in West Greenland and Canada from 1993 through 1999, using satellite-linked data recorders. Narwhals spent less time at the surface than belugas did, and the surfacing time of belugas also varied between localities. No clear differences in surfacing time were associated with the time of day, but belugas tended to make more dives during the night than during the day. Despite large variability in surfacing behaviour among individual whales, time spent at the surface by both species declined from August through November. The few data collected from Narwhals from November to February indicate that surfacing times remained low during this period although more than 25% of each 6 h period was spent at the surface. Whales made between 2 and 20 dives per hour, and Narwhals made significantly fewer dives than did belugas, for which number of dives varied with locality. The number of dives deeper than 8 m declined substantially during the autumn for belugas and Narwhals that were moving offshore. When travelling, the whales apparently made fewer dives than at other times.
Heide-jørgensen, Mads Peter - One of the best experts on this subject based on the ideXlab platform.
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A comparison of image and observer based aerial surveys of Narwhal
'Wiley', 2019Co-Authors: Broker, Koen C. A., Hansen, Rikke G., Leonard, Kathleen E., Koski, William R., Heide-jørgensen, Mads PeterAbstract:From 25 to 30 August 2014 a double-observer line-transect survey was conducted over Melville Bay, home to one of two summering populations of Narwhal (Monodon monoceros) off West Greenland. A total of 1,932 linear kilometers was surveyed along 33 transects. In addition to using observers, the aircraft was equipped with two oblique cameras to capture a comparable data set. Analysts reviewed the images for Narwhal sightings, which were then matched to the observer sightings. The objectives of the study were to determine advantages and disadvantages of the detection capabilities of both methodologies, and to conduct a comparative analysis of population abundance estimates. Correcting for the truncated detection distance of the images (500 m), the image analysts recorded more sightings (62) and a lower mean group size (2.2) compared to aerial observers (36 and 3.5, respectively), resulting in comparable numbers of individuals detected by both platforms (135 vs. 126). The abundance estimate based on the image sightings was 2,536 (CV = 0.51, 95% CI: 1,003-6,406), which was not significantly different from the aerial observers estimate of 2,596 individuals (CV = 0.51; 95% CI: 961-7,008). This study supports the potential of using UAS for marine mammal abundance studies
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Data from: Paradoxical escape responses by Narwhals (Monodon monoceros)
2017Co-Authors: Williams, Terrie M., Blackwell, Susanna B., Richter Beau, Sinding, Mikkel-holger S., Heide-jørgensen, Mads PeterAbstract:Until recent declines in Arctic sea ice levels, Narwhals (Monodon monoceros) have lived in relative isolation from human perturbation and sustained predation pressures. The resulting naïvety has made this cryptic, deep-diving cetacean highly susceptible to disturbance, although quantifiable effects have been lacking. We deployed a submersible, animal-borne electrocardiograph-accelerometer-depth recorder to monitor physiological and behavioral responses of East Greenland Narwhals after release from net entanglement and stranding. Escaping Narwhals displayed a paradoxical cardiovascular down-regulation (extreme bradycardia with heart rate ≤4 beats per minute) superimposed on exercise up-regulation (stroke frequency >25 strokes per minute and energetic costs three to six times the resting rate of energy expenditure) that rapidly depleted onboard oxygen stores. We attribute this unusual reaction to opposing cardiovascular signals—from diving, exercise, and neurocognitive fear responses—that challenge physiological homeostasis
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Narwhals and seismic exploration: Is seismic noise increasing the risk of ice entrapments?
Elsevier Ltd. Published by Elsevier Ltd., 2013Co-Authors: Heide-jørgensen, Mads Peter, Hansen, Rikke Guldborg, Westdal Kristin, Reeves, Randall R., Mosbech AndersAbstract:AbstractThere is great interest in exploring and exploiting hydrocarbon resources in the Arctic, and one of the main methods of locating and assessing such resources is seismic survey. Marine seismic surveys involve the use of airguns that introduce high-energy noise to the Arctic’s largely pristine underwater acoustic environment. Narwhals may be particularly sensitive to this noise but so far no studies have addressed the question of direct effects of high-energy airgun pulses on these animals. We are concerned about the possibility that three large recent ice entrapments were causally linked to seismic survey activities. On these occasions Narwhals remained in coastal summering areas until well into the fall and early winter season, delaying their annual offshore migration and becoming lethally entrapped by rapidly forming fast ice. About 1000 Narwhals died in an ice entrapment in Canada in 2008 and about 100 in two entrapments in Northwest Greenland in 2009–10. We conclude that studies of the direct effects of seismic surveys on Narwhals are urgently needed and should ideally precede further seismic surveys in Narwhal habitats
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Characteristics of acoustic recordings of Narwhals (Monodon monoceros) north of Disko Island, April 2007 and 2009
PANGAEA, 2012Co-Authors: Stafford, Kathleen M, Laidre, Kristin L, Heide-jørgensen, Mads PeterAbstract:A total of 1,690 individual Narwhal nonecholocation sounds were recorded over 5 h in 2007 and 2009. Each sound was classified as either tonal (FM) or pulsed (amplitude modulated). Omnipresent in all the recordings were the songs of bearded seals, Erignathus barbatus, which were often so loud and numerous that the lower frequency ranges of Narwhal sounds could not be distinguished
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Sea ice habitat characteristics and number of Narwhal (Monodon monoceros) sightings in Disko Bay, West Greenland
PANGAEA, 2011Co-Authors: Laidre, Kristin L, Heide-jørgensen, Mads PeterAbstract:There is a paucity of information on abundance, densities, and habitat selection of Narwhals Monodon monoceros in the offshore pack ice of Baffin Bay, West Greenland, despite the critical importance of winter foraging regions and considerable sea ice declines in the past decades. We conducted a double-platform visual aerial survey over a Narwhal wintering ground to obtain pack ice densities and develop the first fully corrected abundance estimate using point conditional mark-recapture distance sampling. Continuous video recording and digital images taken along the trackline allowed for in situ quantification of winter Narwhal habitat and for the estimation of fine-scale Narwhal habitat selection and habitat-specific sighting probabilities. Abundance at the surface was estimated at 3484 (coefficient of variation [CV] = 0.46) including whales missed by observers. The fully corrected abundance of Narwhals was 18 044 (CV = 0.46), or approximately one-quarter of the entire Baffin Bay population. The Narwhal wintering ground surveyed (~9500 km**2) had 2.4 to 3.2% open water based on estimates from satellite imagery (NASA Moderate Resolution Imaging Spectroradiometer) and 1565 digital photographic images collected on the trackline. Thus, the ~18 000 Narwhals had access to 233 km**2 of open water, resulting in an average density of ~77 Narwhals/km**2 open water. Narwhal sighting probability near habitats with 50% open water, suggesting Narwhals select optimal foraging areas in dense pack ice regardless of open water availability. This study provides the first quantitative ecological data on densities and habitat selection of Narwhals in pack ice foraging regions that are rapidly being altered with climate change
Steven H. Ferguson - One of the best experts on this subject based on the ideXlab platform.
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Marine mammal biodiversity and rare Narwhal (Monodon monoceros) observations near northern Ellesmere Island, Canada
'Wiley', 2021Co-Authors: Cody G. Carlyle, Katie R. N. Florko, Brent G. Young, David J. Yurkowski, Christine Michel, Steven H. FergusonAbstract:Abstract A climate‐driven decline of sea ice has increased international interest in understanding the ecology of seldom studied high‐Arctic regions projected to retain the last remnants of summer sea ice. Arctic marine mammals are vulnerable to future environmental change due to their high dependence on sea ice. We completed aerial surveys in August 2019 to document the occurrence and location of marine mammals within the recently designated Tuvaijuittuq Marine Protected Area which acts as a last refuge for ice‐associated species. We present photographic evidence of Narwhals (Monodon monoceros), Atlantic walruses (Odobenus rosmarus), bearded seals (Erignathus barbatus), and ringed seals (Pusa hispida) in Archer Fjord, northern Ellesmere Island, Nunavut, Canada (81°14′–81°49′ N). We discuss these observations in the context of historical records and more recent opportunistic sightings from the region to support the hypothesis of an expansion north of the currently accepted range of Narwhal. The diversity and number of observations of marine mammals in Archer Fjord is a striking contrast to the relative scarcity of the rest of the surveyed region, with very few observations of ringed seals throughout the more northerly study area. Our observations highlight opportunities to further explore high‐latitude areas that may host unique marine mammal biodiversity in the region, including Narwhal
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trace element and stable isotope analysis elucidate stock structure in a Narwhal monodon monoceros population with no genetic substructure
Canadian Journal of Zoology, 2019Co-Authors: Steven H. Ferguson, Cortney A Watt, Claire HornbyAbstract:Chemical composition of tissues can act as a biological tag to discriminate among groups of animals that inhabit different areas. In Canada, subsistence hunting of the Baffin Bay Narwhal (Monodon m...
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sensory ability in the Narwhal tooth organ system
Anatomical Record-advances in Integrative Anatomy and Evolutionary Biology, 2014Co-Authors: Martin T Nweeia, Jack Orr, Steven H. Ferguson, Cortney A Watt, Frederick C Eichmiller, Peter V Hauschka, James G Mead, Gretchen A Donahue, Charles W PotterAbstract:The erupted tusk of the Narwhal exhibits sensory ability. The hypothesized sensory pathway begins with ocean water entering through cementum channels to a network of patent dentinal tubules extending from the dentinocementum junction to the inner pulpal wall. Circumpulpal sensory structures then signal pulpal nerves terminating near the base of the tusk. The maxillary division of the fifth cranial nerve then transmits this sensory information to the brain. This sensory pathway was first described in published results of patent dentinal tubules, and evidence from dissection of tusk nerve connection via the maxillary division of the fifth cranial nerve to the brain. New evidence presented here indicates that the patent dentinal tubules communicate with open channels through a porous cementum from the ocean environment. The ability of pulpal tissue to react to external stimuli is supported by immunohistochemical detection of neuronal markers in the pulp and gene expression of pulpal sensory nerve tissue. Final confirmation of sensory ability is demonstrated by significant changes in heart rate when alternating solutions of high-salt and fresh water are exposed to the external tusk surface. Additional supporting information for function includes new observations of dentinal tubule networks evident in unerupted tusks, female erupted tusks, and vestigial teeth. New findings of sexual foraging divergence documented by stable isotope and fatty acid results add to the discussion of the functional significance of the Narwhal tusk. The combined evidence suggests multiple tusk functions may have driven the tooth organ system's evolutionary development and persistence. Anat Rec, 297:599–617, 2014. © 2014 Wiley Periodicals, Inc.
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Local Passive Acoustic Monitoring of Narwhal Presence in the Canadian Arctic: A Pilot Project
2011Co-Authors: Steven H. Ferguson, Murray M. HumphriesAbstract:ABSTRACT. Long-term community-based monitoring of Narwhals (Monodon monoceros) is needed because Narwhals are important to local Inuit and are facing changes in their environment. We examined the suitability of passive acoustic recording for monitoring Narwhals, using data gathered in the Canadian Arctic from an autonomous acoustic recorder (Repulse Bay, 2006) and a hand-held digital recorder (Koluktoo Bay, 2006 – 08). We found a relationship between the number of Narwhals observed passing a fixed point and the number of calls heard. In addition, we found that an automated call detector could isolate segments of recording containing Narwhal vocalizations over long recording periods containing non-target sound, thus decreasing the time spent on the analysis. Collectively, these results suggest that combining passive acoustic sampling with an automated call detector offers a useful approach for local monitoring of the presence and relative abundance of Narwhals. Key words: animal behaviour, automated detection, Baffin Island, marine mammal, Narwhal, participatory monitoring RÉSUMÉ. La nécessité d’avoir un programme communautaire de surveillance à long terme des narvals (Monodon monoceros) s’avère évidente étant donné que les narvals revêtent de l’importance aux yeux des Inuits de la région et que leur environ-nement est en pleine évolution. Nous explorons la pertinence d’un programme de surveillance par acoustique passive pour les populations de narvals à partir de données récoltées dans l’Arctique canadien à l’aide d’une enregistreuse autonome (Repulse Bay, 2006) et d’une enregistreuse portable (Koluktoo Bay, 2006 – 2008). Grâce à des enregistrements accompagnés d’obser-vations sur le terrain, nous avons trouvé une corrélation entre le nombre de vocalisations entendues et le nombre de narval
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a little less arctic top predators in the world s largest northern inland sea hudson bay
2010Co-Authors: Steven H. Ferguson, Lisa L Loseto, Mark L MalloryAbstract:Dedication.- Introduction.- 1. Physical, chemical, and biological conditions of the Hudson Bay marine region.- 2. Changing Sea Ice Conditions in Hudson Bay, 1979-2005.- 3. Importance of eating capelin: Unique dietary habits of Hudson Bay beluga.- 4. Migration route and seasonal home range of the Northern Hudson Bay Narwhal (Monodon monoceros).- 5. Polar bear ecology and management in Hudson Bay in the face of climate change.- 6. The rise of killer whales as a major Arctic predator.- 7. Hudson Bay ringed seal: ecology in a warming climate.- 8. Past, present, and future for bowhead whales (Balaena mysticetus) in northwest Hudson Bay.- 9. Effects of climate change, altered sea-ice distribution and seasonal phenology on marine birds.- 10. Temporal trends in beluga, Narwhal and walrus mercury levels: links to climate change.- 11. Hudson Bay ecosystem: Past, present, and future.- 12. Population genetics of Hudson Bay marine mammals: current knowledge and future risks.- 13. Understanding and managing wildlife in Hudson Bay under a changing climate: Some recent contributions from Inuit and Cree ecological knowledge.- 14. The future of Hudson Bay: New directions and research needs.- Index
