Download or read book Factors Influencing the Acoustic Behavior and Nearshore Residence of the Gray Whale Eschrichtius Robustus Along Their Migration Route written by and published by . This book was released on 2009 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our long-term goal is to quantify the acoustic behavior of gray whales in the coastal waters of the Northeast Pacific Ocean and to characterize the link between coastal residency patterns of these migratory mammals and the distribution of hyperbenthic swarms of their primary prey, mysids.
Download or read book Migrating Eastern North Pacific Gray Whale Behavior Compared Over Multiple Timescales written by Regina Anne Guazzo and published by . This book was released on 2018 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mysticetes (baleen whales) often make long, annual migrations from high latitude summer feeding areas to low latitude wintering areas. Eastern North Pacific gray whales (Eschrichtius robustus) migrate within a few kilometers from shore for most of their route from summer feeding areas in the Bering, Chukchi, and Beaufort Seas to wintering areas in the lagoons along the south-western coast of the Baja California Peninsula in Mexico. This dissertation combines passive acoustic recordings, infrared camera video, and visual sightings to investigate gray whale behavior and how it changes across different timescales. I use a four-element hydrophone array in central California to present the first published full-season acoustic monitoring and tracking of migrating gray whales. I describe the characteristics of calls produced by migrating gray whales and analyze how these characteristics change due to propagation. I show that gray whale behavior changes on diel and seasonal timescales. Notably, gray whales increase their vocalizations at night but their mean swimming behavior does not change, contrary to previous assumptions used in population size estimates. Over seasonal timescales, vocalizing gray whale swimming behavior aligns with previous observations. I explore how passive acoustic and infrared camera monitoring can help quantify whales by calculating cue rates or call and blow rates for migrating gray whales. Acoustic calling rates indicate that the gray whale population size is greater than estimated using visual sightings alone and that calling rate increases over the southbound migration. Infrared camera blow rates are less affected by whale behavior and are useful for daytime and nighttime monitoring, but are limited by visibility and distance. To understand gray whale behavior over seven migration seasons, I use visual daily counts at two sites and single-hydrophone call detections which indicate that migratory behavior seems to be driven more by intrinsic than the tested environmental factors. I find that the proportion of the population using a coastal route through the Southern California Bight, especially past Los Angeles, increased over these years. Understanding the behavior of migrating gray whales will help improve abundance estimates and determine how these whales may be impacted by nearshore anthropogenic activities and climate change.
Download or read book Anthropogenic Disturbance of Western Gray Whale Behavior Off Sakhalin Island Russia written by Glenn Andrew Gailey and published by . This book was released on 2013 with total page 283 pages. Available in PDF, EPUB and Kindle. Book excerpt: The western North Pacific population of gray whales (Eschrichtius robustus) is critically endangered of extinction. The population size is estimated to be 131 individuals with 31 reproductive females. Throughout their potential home range, the western gray whale population face several threats to their future survival. On their only known feeding grounds off the northeastern coast of Sakhalin Island, Russia, anthropogenic activity has increased in the past decade due to oil and gas exploration and platform/pipeline construction. This dissertation examines the influences of geophysical seismic surveys (pulse sounds) and platform/pipeline installation (continuous sounds). Each chapter progressively improves upon behavioral models that assess changes in gray whale movements and respirations relative to anthropogenic activity. Theodolite tracking and focal follow methodologies were employed to collect gray whales' movement and respiration information during and in the absence of anthropogenic activity. Spatial, temporal, environmental, and acoustic (pulse and/or continuous) sound levels and non-sound related anthropogenic variables were included as explanatory variables to examine their influence on movement and respiration response variables, such as speed, orientations, dive/surface time, breathing rates, etc. During the 3-D seismic activity, gray whales traveled faster, changed directions of movement less, were recorded farther from shore and stayed underwater longer between respirations as the received sound level exposure increased. During platform/pipeline installations, western gray whales increased their distance from shore with indicators of stress (rapid breathing) and observed to be sensitive to close distance of approach by vessels. No acoustic influence on western gray whale behavior was found during a 4-D seismic survey; however, sample sizes were small in this study to sufficiently detect more subtle to moderate changes in gray whale behavior. These studies illustrate short-term influences anthropogenic activity had on western gray whale behavior which could lead to longer-term responses that may be detrimental to the survival of certain individuals and/or the population. A comprehensive analyses are proposed to increase sample sizes to identify subtle to moderate behavioral changes as well as examine alternative hypotheses to the null hypothesis of no impact used in this dissertation. With the potential to displace individuals/population out of critical feeding habitats needed for their annual survival and the expected increase of anthropogenic activity in the future, this dissertation highlights the importance to monitor and identify problems and suggest alternatives to development/activities that may be impacting this endangered population of gray whales. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/149559
Download or read book The Gray Whale Eschrichtius Robustus written by Mary Lou Jones and published by Academic Press. This book was released on 2012-12-02 with total page 625 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Gray Whale: Eschrichtius robustus provides an introduction to the understanding of Eschrichtius robustus or the gray whale. This book explores the life processes, reproduction, and growth of large cetacean populations. Organized into four parts encompassing 25 chapters, this book begins with an overview of the gray whale evolution, fossils, and subfossil remains, range, and systematics in historical times. This text then presents the historical of gray whale exploitation and the economic importance of these whales to humans. Other chapters consider the gray whale migration, abundance, and seasonal distribution in the wake of the California population's recovery from depletion. This book discusses as well the methods used in shore-based censuses during migration and in aerial surveys of gray whales taken on their winter grounds. The final chapter deals with some innovative approaches to the study of free-ranging cetaceans. This book is a valuable resource for anthropologists, paleontologists, biologists, and naturalists.
Download or read book Sound Production of Gray Whales Eschrichtius Robustus Along Their Migration Route written by Nicole Leslie Crane and published by . This book was released on 1992 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the Workshop to Review and Evaluate Whale Watching Programs and Management Needs November 14 16 1988 Monterey California written by and published by . This book was released on 1989 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gray Whale Monitoring Study written by and published by . This book was released on 1989 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Assessment of Gray Whale Movements in Acoustically Changing Nearshore Environments written by Bruce R. Mate and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This grant helped fluid six field seasons over four years. The initial objective was to investigate the movements of gray whales in environments with varying levels of development and acoustic stimuli. The objective eventually broadened to identify the critical habitats of whales and investigate how natural variability and human activities affect the ways endangered whales utilize their environments. To accomplish these objectives, gray whales (1996) and humpbacks (1998) were tagged in Baja, blue whales were tagged along California (1998-99), and humpbacks were tagged around Hawaii (1998-99). The detailed route and rate of a gray whale's northbound migration was determined. Female gray whales with calves stayed in lagoons much longer than singular whales (x=22 days) suggesting the importance of these areas for development of newborn calves. We determined: Hawaiian humpbacks' movements in and around the winter reproductive grounds, various spring migration routes, new feeding areas, associations with oceanographic features, and movement patterns within the feeding grounds. Tagged blue whales were tracked during their feeding season off California, south along the Baja coast during their fall migration and to an upwelling area near the equator which is likely where some of the population goes to breed and calve.
Download or read book System Open Market Account written by and published by . This book was released on 1988 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Demography Migrations and Behavior of Gray Whales written by Steven Lindsay Swartz and published by . This book was released on 1986 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Distribution Numbers and Behavior of Gray Whales in the Channel Islands National Marine Sanctuary During the Southward Migration January 1987 written by Mary Lou Jones and published by . This book was released on 1988 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Behavioral Ecology of Summer Resident Gray Whales Eschrichtius Robustus Feeding on Mysids in British Columbia Canada written by Lei Lani Stelle and published by Ann Arbor, Mich. : University Microfilms International. This book was released on 2001 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Boat Traffic on the Behavior of Gray Whales Eschrichtius Robustus in Bahia Magdalena Baja California Sur Mexico written by Francisco Ollervides and published by . This book was released on 1997 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ecological Interrelationships Between Summer Resident Gray Whales Eschrichtius Robustus and Their Prey Mysid Shrimp Holmesimysis Sculpta and Neomysis Rayi Along the Central Oregon Coast written by Carrie Newell and published by . This book was released on 2010 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ecological interaction between the largest coastal predator, the gray whale (Eschrichtius robustus) and the most abundant shallow water marcrozooplanktonic prey, mysids, were examined in a poorly-understood predator-prey relationship along the central Oregon coast. From 2002-2008, 83 seasonal gray whales were identified. These whales returned each year around Memorial Day and stayed until mid October preying on mysid swarms as determined from fecal material and feeding behaviors. The two mysid species preyed upon were Holmesimysis sculpta and Neomysis rayi. This resea rch provided information on the spatial/temporal pattern of mysid distribution, patch composition, density and reproductive dynamics of the mysids and how they affect gray whale distribution, abundance, residency and body condition. A determination was also made how climate affected predator-prey interactions during a warm water climate regime in 2005. In 2005, gray whales spent little time in foraging and fewer days in residence than in other years and many were in poor body condition. Mysid swarms were also sparse until August and a large percentage of females had empty brood pouches.
Download or read book Social Context of Gray Whale Eschrichtius Robustus Sound Activity written by Sarah Marie Charles and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis examines sound production of eastern gray whales (Eschrichtius robustus) in the wintering lagoons to determine whether sound use is a function of social context. Proportions of sounds used, parameters of each sound class, and rates of sounds were compared among social contexts. Data revealed the strong possibility of context-specific use for particular sound classes. Additionally, sound parameters and rates of production varied by social context. These results reflect similar variations in gray whale repertoire throughout their range that may be due to changes in social and behavioral contexts. Gray whale sounds are classified into several classes based on aural and visual characteristics. This study verifies the classification system determined in previous studies, with the exception of class 8, and supports the division of class 1 into subclasses 1a and 1b. Class 1 appeared to be critical during sexual contexts and all highly social contexts, regardless of age and sex class. Although highly recognizable, its parameters exhibited much variation among social contexts; therefore class 1 may communicate graded emotional states in short-range interactions. Other classes of sounds may be utilized for long-distance communication, as startle responses, or "precursors" to the adult repertoire. Frequency-related parameters of all sound classes showed variation among social contexts, but duration demonstrated very little variation. Calf-containing contexts exhibited greatest and most varied frequencies; this is to be expected if gray whale's sound mechanism is related to body and tracheal length. Variation also may indicate that physical maturity or learning play a role in the repertoire development. The lowest and least varied frequencies were observed in adult contexts. Sound production rates also varied by social context. Active adults produced sounds at high rates during short intervals; mixed/unknown contexts were often silent. Calf-containing contexts produced sounds at intermediate rates and were never silent. The correlations demonstrated here between social context and use of sounds will allow for acoustics to be an indicator of group composition, seasonal movements, and social patterns, thus relieving dependency on difficult visual observation. Additionally, such correlations provide preliminary information for determining sound functions.
Download or read book The Life History and Ecology of the Gray Whale Eschrichtius Robustus written by Dale W. Rice and published by . This book was released on 1971 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Marine Mammals Ashore written by Joseph R. Geraci and published by National Aquarium in Baltimore. This book was released on 2005 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive manual for understanding and carrying out marine mammal rescue activities for stranded seals, manatees, dolphins, whales, or sea otters.
