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Author: Kristin Westdal Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Beluga whales (Delphinapterus leucas) are an Arctic cetacean with circumpolar distribution. They are known to have distinct, lengthy and consistent migration paths to and from summer and wintering grounds. The Western Hudson Bay beluga population, the largest summering aggregation in the world, inhabits three main estuaries in the summer season. Little protection is afforded to them here, and little is known of the specific details of their summer distribution and factors affecting that distribution. Using a combination of satellite telemetry, aerial photos, satellite data, and visual observations and historical reports, investigations into factors affecting beluga distribution in Western Hudson Bay were conducted. An examination into beluga age class distribution near the Churchill and Seal River estuaries, using aerial survey imagery, suggested that belugas may not be segregating by age in summer, however the Seal River estuary may be more important from a calf-rearing perspective. Belugas use a greater home range than we would expect, based on historical range data, in the face of predation by their main predator, the killer whale (Orcinus orca). Killer whales are sighted more frequently in Hudson Bay than historically, and results presented here show that ice entrapments, occurring with higher frequency in the future, may impact distribution of beluga as killer whales expand their range and occurrence in Hudson Bay. Finally, an assessment of beluga behaviour in the presence of whale-watching vessels showed that beluga response to vessels varied but the probability of travelling behaviour was significantly greater with distance from vessels; belugas also appear to be spending more time interacting with vessels now, as compared to 15 years ago when there were fewer whale-watching vessels. The results found through this research are useful in informing climate change implications, marine-protected area boundaries, policy and marine spatial planning, and subsistence harvest management.
Author: Kristin Westdal Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Beluga whales (Delphinapterus leucas) are an Arctic cetacean with circumpolar distribution. They are known to have distinct, lengthy and consistent migration paths to and from summer and wintering grounds. The Western Hudson Bay beluga population, the largest summering aggregation in the world, inhabits three main estuaries in the summer season. Little protection is afforded to them here, and little is known of the specific details of their summer distribution and factors affecting that distribution. Using a combination of satellite telemetry, aerial photos, satellite data, and visual observations and historical reports, investigations into factors affecting beluga distribution in Western Hudson Bay were conducted. An examination into beluga age class distribution near the Churchill and Seal River estuaries, using aerial survey imagery, suggested that belugas may not be segregating by age in summer, however the Seal River estuary may be more important from a calf-rearing perspective. Belugas use a greater home range than we would expect, based on historical range data, in the face of predation by their main predator, the killer whale (Orcinus orca). Killer whales are sighted more frequently in Hudson Bay than historically, and results presented here show that ice entrapments, occurring with higher frequency in the future, may impact distribution of beluga as killer whales expand their range and occurrence in Hudson Bay. Finally, an assessment of beluga behaviour in the presence of whale-watching vessels showed that beluga response to vessels varied but the probability of travelling behaviour was significantly greater with distance from vessels; belugas also appear to be spending more time interacting with vessels now, as compared to 15 years ago when there were fewer whale-watching vessels. The results found through this research are useful in informing climate change implications, marine-protected area boundaries, policy and marine spatial planning, and subsistence harvest management.
Author: Alexander J. Smith Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Most beluga whales (Delphinapterus leucas) (Pallas 1776) living in areas of seasonal sea ice use estuaries periodically during summer. Beluga estuary-use hypotheses include feeding, calving, moulting, killer whale (Orcinus orca) predation, human predation, thermal advantage, and phylogenetic inertia. The hypotheses may not be mutually exclusive and may vary with populations or regions. This study describes aspects of beluga whale summer-ecology by studying the association between inter-annual water levels and beluga habitat selection in the Nelson River estuary. Flow rates from upstream Limestone Dam doubled from the dry years of 2002-2004 to the wet year of 2005. I used radio-tracking data (N=15, 2002-2005) and aerial surveys (2003, 2005) to test the hypothesis (H1) that belugas were farther out in the estuary during the wet year. Model variables included year, day, time, tide and age-sex. Observed location-habitat distances for the radio-tracking and aerial survey data were compared to the random equivalents using a Kolmogorov-Smimov (KS) test. A cumulative sign test determined the timing of a beluga shift in movement behaviour on August 10th. Pre-August 10th radio-tracking locations provided the spatial-temporal boundary of the Nelson River estuary. General Linear Models (GLM) for both the telemetry and aerial survey data show an association between beluga distance to the river-mouth and year. Study results provide evidence to weigh the main estuary-use hypotheses and contriubte to knowledge of beluga ecology and management.
Author: Donna D. W. Hauser Publisher: ISBN: Category : White whale Languages : en Pages : 206
Book Description
Sea ice is disappearing at unprecedented rates in the Pacific Arctic with potential impacts to ice-associated marine predators that migrate to this seasonally accessible and productive ecosystem. In this dissertation I used satellite telemetry data spanning 1993-2012 collected from two migratory populations of beluga whales (Delphinapterus leucas) in the Pacific Arctic (i.e., Eastern Chukchi Sea and Eastern Beaufort Sea populations) to investigate how loss of sea ice and changes in other environmental factors affect distribution, movement, and behavior. I quantified fidelity to summer areas, sexual segregation, and migration timing as well as variations in diving behavior among regions. These analyses illustrate that population-scale patterns of philopatry, migration, and foraging are mediated by the combined effects of seasonal sea ice and oceanographic fluctuations, prey distribution, and social interactions. I also addressed the question of whether belugas would adjust their distribution, migration, and behavior to shifting sea ice conditions and to what extent matrilineally-learned behavior might supersede environmental forcing through the development of resource selection functions. Results indicate that sea ice is a contributing factor but not sole determinant of beluga habitat preferences. One population (Eastern Chukchi Sea) exhibits delayed fall migration in response to later sea ice freeze-up. Changing environmental conditions also seem to favor deeper, longer dives for this population. There were few overall differences in preferred habitat selection during 1990-2014, and summer distribution appears to be governed by philopatry rather than ice conditions. These results correspond to a conclusion that Eastern Chukchi Sea belugas are responding to a changing Pacific Arctic environment through behavioral plasticity in migration timing and foraging behavior. In contrast, there were few examples where migration timing or sea ice associations of Eastern Beaufort Sea belugas changed between the 1990s and 2000s. Taken as a whole, these results suggest population-specific responses by belugas in the face of fluctuating sea ice conditions. Across the circumpolar Arctic, some beluga populations may be more likely than others to adapt and persist in a changing climate.
Author: Thomas G. Smith Publisher: ISBN: Category : Nature Languages : en Pages : 228
Book Description
Collection of 14 articles representing a cross-section of current research on beluga whales, Delphinapterus leucas, in North American waters.
Author: Emma Ausen Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Western Hudson Bay is undergoing habitat changes associated with increased anthropogenic activities including vessel traffic from shipping and whale watching ecotourism. These river estuaries are habitat for the Western Hudson Bay (WHB) beluga whale, the largest know beluga population. This thesis addresses two important questions, which environmental conditions contribute to critical beluga habitat in the western Hudson Bay, and what is the response of beluga to tourism vessel traffic in the Churchill River estuary. Beluga were identified in nadir imagery from a 2018 summer aerial survey of the Nelson, Churchill and Seal River estuaries, and oblique images taken of the Churchill River estuary in August 2020. The location of beluga within each survey area was modeled with respect to remotely sensed environmental data. Beluga habitat use was found to be associated with rivers as well as the concentration of total suspended sediments, and colored dissolved organic matter. Using environmental characteristics, a previously unidentified important habitat unit for beluga was discovered in the Knife River estuary. Distance measurements between belugas and tourist vessels were obtained from oblique images using trigonometric equations and georeferencing points taken in the Churchill River estuary. Through distance analysis, it was found that beluga showed attraction to kayaks, avoidance to paddleboards, and independence from motorboats and Zodiacs. Results from this thesis should inform management decisions for the WHB beluga population, including the establishment of a National Marine Protected Area which is currently under consideration.
Author: D. W. Doidge Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
"Beluga whales (Delphinapterus leucas) occupy Hudson Bay in summer where they are an important source of country-food for the Inuit. Two stocks have been identified; the western stock is estimated to contain at least 23,000 animals, approximately 15 times larger than the eastern stock (Richard et al 1990). The two stocks are genetically distinct (Brown et al 1997). The eastern stock has been designated by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as threatened and a quota system has been applied to the Inuit subsistence harvest on the northern Quebec coast. The western stock has no quota since harvest levels are lower than the estimated sustainable yield. Aerial surveys in 1985 (Smith and Hammill 1986) and 1993 (DFO unpublished) indicate the summer distribution of beluga whales extends between the Quebec coast (Nunavik) and Sanikiluaq (Belcher Islands). Also, satellite tags, which transmitted for a short time in 1993, showed one whale, tagged at the Little Whale River on the Quebec coast, frequented areas offshore as far as the Belchers. These data would indicate a common stock between Nunavik and Sanikiluaq. However, genetic analysis indicates whales harvested in Sanikiluaq are more similar genetically to western Hudson beluga than those caught along the eastern Hudson Bay coast, just 100 km distant. The conflicting scientific information (genetic make-up vs distribution data) has led some Nunavik Inuit to question the scientific validity of the existing co-management regime and quota system. The number of satellite tags deployed in 1993 (DFO unpublished data) has not been sufficient to clearly resolve the movements of whales that frequent the Quebec coast. The hunters' association of the Nunavik Inuit (HFTA) requested that the issue of stock identity be resolved. A resolution supporting the satellite tagging project was passed at the HFTA's annual general meeting in 1998. With support from World Wildlife Fund Canada, Fisheries and Oceans and Makivik Corporation, three satellite tags were deployed on belugas at the Nastapoka River in 1999. ... In August, the tagged animals frequented the offshore between the mainland coast and the Belcher Islands, an area indicated to be the summer distribution of belugas previously by aerial surveys. While the single, gray animal ventured to the Belcher Islands, the time spent in that vicinity accounted for a small proportion of the time it was tracked (ca. 8%). The two adults with calves did not venture as far to the west. The sample size of tagged animals is too small to estimate the probability of animals that occupy the Nastapoka being caught at the Belchers. However, analysis of the DNA of belugas harvested at the Belchers indicates that the number having the eastern Hudson Bay haplotype is low. The degree of site-tenacity and estuarine use appears to be variable. Other studies demonstrate that belugas will return to the locality of tagging (Orr et al 1998, DFO unpublished data). However, the three whales tagged by us, did not appear to re-enter Nastapoka Estuary. Radio transmitters are becoming more dependable enabling data to be gathered over a longer period of time. Two tags transmitted long enough to indicate that whales remain in the Hudson Bay Area until early October. The start of a northward migration, presumably to over-wintering grounds in Hudson Strait, was documented for one whale until its transmitter sopped signaling near Puvirnituq in late October. A large quantity of data has been received from these satellite tags. The inshore areas of beluga habitat, such as estuaries, are well documented from traditional knowledge and scientific studies. The data from satellite tagged whales show areas, offshore of the Nastapoka Islands, where the whales have remained for several days. The bathymetry of these locations will be examined in relation to the whales' diving activities to better understand habitat-use of beluga whales in eastern Hudson Bay. This analysis is scheduled for Winter 2000-01. The method of using surgical pins to attach the transmitter to the whale's back remains invasive, but no alternative has yet been found. The number of whales tagged has been kept to a minimum. A thorough review of the dive data will determine if a realistic correction factor to account for submerged whales, not counted during aerial surveys can be estimated, or whether further tagging is needed"--ASTIS [online] database.
Author: Lucy F. Romeo Publisher: ISBN: Category : Spatial behavior in animals Languages : en Pages : 92
Book Description
The known distribution of beluga whales ranges from sub-Arctic to Arctic waters where they migrate in pods in response to environmental factors such as the presence of sea ice and prey. This study uses bivariate and multivariate analysis techniques to measure how environmental covariates are associated with the spatial-temporal distribution of beluga whales. Exploratory data analysis was used to determine the relationship among environmental covariates: bathymetry, slope, sea surface temperature, and distance to sea ice. Spatial analyses were used to determine the probability of occurrence of beluga whales in the northeastern Chukchi and southwestern Beaufort seas, based on each environmental covariate for the autumn months of the two study periods, from 2000 to 2006 and from 2008 to 2012. Findings from this study suggest that correlations exist between SST and distance to sea ice, and depth and distance to sea ice, and that beluga whales may prefer areas of relatively steep slope and associated increasing depth along the continental slope. Probability of occurrence maps were created for September and October for each year, based on beluga whale preference and avoidance for each environmental covariate. Areas of preference, or high probability of occurrence, had more beluga whale sightings than expected. And areas of avoidance, or low probability of occurrence, had less beluga whale sightings than expected. Model validation included randomly dividing observational data from September of 2011 into a training (70%) and testing (30%) dataset, then creating a probability of occurrence model based on the training dataset and comparing the results to the locations of the testing dataset. Outputs from the analyses can help guide studies of beluga environmental covariate preferences and the possible influences on their occurrence. Better understanding of the spatial distribution of beluga whales can provide a tool for better management practices. Improved practices in management and conservation of habitat for beluga whales will impact indigenous communities who rely on marine mammals as cultural and consumable resources.
Author: Julie Turgeon Publisher: ISBN: Category : White whale Languages : en Pages : 14
Book Description
There are still concerns from Nunavik hunters about the stock structure of beluga that are hunted in the coastal waters around northern Quebec. The addition of new samples allows the Hudson Bay stock complex to be re-examined. This report also focuses on estimating the contribution of distinct beluga stocks to the harvest of Nunavik sectors and surrounding communities. It provides a new seasonal and regional picture on these contributions by applying a Genetic Mixture Analysis that includes the three stocks that could contribute to the harvest in Northeastern Hudson Bay, Hudson Strait, and Ungava Bay. It also addresses the status of whales from Sanikiluaq.
Author: Kristin Westdal
Author: Kristin Westdal
Author: Alexander J. Smith
Author: Donna D. W. Hauser
Author: Thomas G. Smith
Author: Emma Ausen
Author: Donald J. Hansen
Author: D. W. Doidge
Author: Lucy F. Romeo
Author: Julie Turgeon
Author: Samuel John Mancuso