Download or read book The Foraging Ecology of Harbor Seals Phoca Vitulina Richardsi in Southcentral Prince William Sound Alaska 1994 1997 written by Tracey A. Gotthardt and published by . This book was released on 2001 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Fourteen harbor seals (Phoca vitulina richardsi) from southcentral Prince William Sound (PWS), Alaska, were outfitted with satellite-linked time depth recorders (SDRs) to monitor their movements and diving behavior. I subsequently examined available information on forage fish abundance, composition and distribution to evaluate whether the distribution and diving behaviors of seals corresponded to the seasonal and temporal distribution of their prey. A wide array of forage fishes were seasonally available to PWS harbor seals. Seasonal differences were apparent in depth of dives and distances moved by seals to foraging areas. It is likely that the two were inter-related, as the distant areas used by seals were also the deepest. Seasonal differences in diving depths and localities were likely due to seasonal changes in prey availability. Seals dove deeper and increased foraging ranges in winter, suggesting prey availability in winter may be greatly reduced compared to spring or summer"--Leaf ii.
Download or read book Foraging Ecology Diving Behavior and Migration Patterns of Harbor Seals Phoca Vitulina Richardii from a Glacial Fjord in Alaska in Relation to Prey Availability and Oceanographic Features written by Jamie Neil Womble and published by . This book was released on 2012 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the movement behavior and foraging strategies of individuals across multiple spatial and temporal scales is essential not only for understanding the biological requirements of individuals but also for linking individual strategies to population level effects. Glacial fjords scattered throughout south-central and southeastern Alaska host some of the largest seasonal aggregations of harbor seals (Phoca vitulina richardii) in the world, and an estimated 15% of the harbor seal population in Alaska is found seasonally at these glacial ice sites. Over the last two decades, the number of harbor seals has declined at two of the primary glacial fjords, in Aialik Bay in south-central Alaska and in Glacier Bay in southeastern Alaska, thus raising concerns regarding the viability of seal populations in glacial fjord environments. From 2004-2009, the foraging ecology, diving behavior, and migration patterns of harbor seals from Glacier Bay National Park, Alaska were examined in relation to prey availability and oceanographic features in Glacier Bay and the surrounding regions of southeastern Alaska. Time-depth recorders, very high frequency transmitters, and satellite-linked transmitters were used to quantify the vertical and horizontal movement patterns of harbor seals in the marine environment. Specifically, (1) I characterized the diving behavior, foraging areas, and foraging strategies of female harbor seals from terrestrial and glacial ice sites relative to prey availability during the breeding season (May-June) in Glacier Bay, (2) I quantified the intra-population variation in at-sea post-breeding season (September-April) distribution and movement patterns of female harbor seals in relation to oceanographic features, (3) I quantified the post-breeding season migration patterns of female harbor seals relative to the boundaries of the marine protected area of Glacier Bay National Park, and (4) I characterized the use of the continental shelf region of the eastern Gulf of Alaska by female harbor seals from Glacier Bay, both as a foraging area and as a migratory corridor in relation to oceanographic features. During the breeding season, there was a substantial degree of intra-population variation in the diving behavior and foraging areas of juvenile and adult female seals from glacial ice and terrestrial sites in Glacier Bay. The presence of multiple diving strategies suggests that differences in the relative density and depth of prey fields in glacial ice and terrestrial habitats in addition to seal age and reproductive status may influence diving and foraging behavior of harbor seals. During the post-breeding season, juvenile and adult female harbor seals ranged extensively beyond the boundaries of the marine protected area of Glacier Bay National Park, throughout the northern inshore waters of southeastern Alaska and the continental shelf region of the eastern Gulf of Alaska between Cross Sound and Prince William Sound, Alaska (up to 900 kilometers away). Seals exhibited a relatively high degree of intra-population variation in their at-sea post-breeding season distribution patterns that may be a function of extrinsic factors such as oceanographic characteristics, which can influence prey availability as well as intrinsic factors including previous experience with foraging areas and seal condition and age. Use of the continental shelf region of the eastern Gulf of Alaska by harbor seals as a foraging area may be due to enhanced biological productivity which may be associated with ephemeral hydrographic and/or static bathymetric features. Despite extensive migrations of seals from Glacier Bay during the post-breeding season, there was a high degree of inter-annual site fidelity of seals to Glacier Bay the following breeding season after seals were captured.
Download or read book Status Review written by John L. Sease and published by . This book was released on 1992 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comparative Foraging Ecology of Pacific Harbor Seals Phoca Vitulina Richardii and California Sea lions Zalophus Californianus in the SouthernCalifornia Bight written by Valerie R. Greenslade and published by . This book was released on 2002 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seasonal Abundance Distribution and Ecology of the Harbor Seal Phoca Vitulina Richardsi on San Miguel Island California written by Brent S Stewart and published by . This book was released on 1981 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Foraging Ecology of the Harbor Seals Phoca Vitulina and California Sea Lions Zalophus Californianus at the Mouth of the Russian River California written by Linda C. Hanson and published by . This book was released on 1993 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Harbor Seal Phoca Vitulina Biology and Management in Alaska written by A. Anne Hoover-Miller and published by . This book was released on 1994 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Foraging Behavior of the Pacific Harbor Seal Phoca Vitulina Richardsi in Humboldt Bay California written by Aicha M. Ougzin and published by . This book was released on 2013 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coastal ecosystems are under intense pressure from anthropogenic and environmental factors in California. Human development, pollution and climate change continue to degrade coastal habitats. Marine predators such as marine mammals that depend on nearshore ecosystems are at risk from these anthropogenic and environmental factors. The Pacific harbor seal (Phoca vitulina richardsi) is one of the most common marine mammals along the coast of northern California and likely to be heavily impacted by changes in the coastal environment, yet little is known about their foraging behavior or habitat use. To accurately predict the response of local marine predators to changes in the coastal environment an understanding of their foraging behavior is required.
Download or read book Harbor Seal Phoca Vitulina Richardsi Census in California June 2 5 30 and July 1 1986 written by Doyle A. Hanan and published by . This book was released on 1987 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Federal Actions Associated with Management and Recovery of Cook Inlet Beluga Whales written by and published by . This book was released on 2008 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monitoring Habitat Use and Trophic Interactions of Harbor Seals in Prince William Sound Alaska written by Kathryn J. Frost and published by . This book was released on 1997 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fisheries Centre Research Reports written by and published by . This book was released on 2005 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Harbor Seal Phoca Vitulina Richardsi Census in California May June 1987 written by Doyle A. Hanan and published by . This book was released on 1988 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Alaska Harbor Seal Research Plan 2000 written by United States. National Marine Fisheries Service and published by . This book was released on 2000 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Examines statewide harbor seal population abundance estimation, stock identification, trends in abundance, general biology and life history, and human interactions.
Download or read book Biology of the Harbor Seal Phoca Vitulina Richardsi in the Gulf of Alaska written by Kenneth W. Pitcher and published by . This book was released on 1979 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Species Account written by Kenneth W. Pitcher and published by . This book was released on 1980 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: A report on harbor seals in the Gulf of Alaska and Bering Sea waters adjacent to Alaska.
Download or read book Foraging Behavior of the Pacific Harbor Seal Phoca Vitulina Richardii in the Pacific Northwest and Potential Impacts of Coastal Hypoxia on Foraging Efficiency written by Sheanna M. Steingass and published by . This book was released on 2014 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last decade, the California Current Large Marine Ecosystem has experienced a trend of increased severity of upwelling-driven coastal hypoxia. This thesis strove to examine the potential upper trophic level impacts of moderate and severe hypoxia in the CCLME. Initially I conducted a literature review of Pacific harbor seal (Phoca vitulina richardii) diet in the regions of Oregon and Washington. Thirteen papers were reviewed which detailed harbor seal foraging studies in Washington, Oregon and the Columbia River from 1931 until 2012. 148 prey species or genera were described in harbor seal diet in Oregon, Washington and the Columbia River. Accordingly, I created energetic individual-based models of harbor seal spatial foraging behavior in response to hypoxia-related habitat compression for three predominant prey species, Pacific herring (Clupea pallasii), English sole (Parophyrs vetulus) and Pacific sandlance (Ammodytes hexapterus). The model was composed of three submodels which simulated hypoxia and spatial foraging, foraging energetics, and dive mechanics. Hypoxia was scaled from 0 to a level of 1, which represented a severe inner-shelf hypoxic or anoxic event in which up to 80% of the inner shelf water column was hypoxic, and species lost 50% of their horizontal habitat. Response variables were also evaluated at the intermediate hypoxia levels of 0.25 and 0.75. A sensitivity analysis was conducted to illuminate which predictor variables drove a variety of response variables. Hypoxia strongly drove energetic balance, travel cost to foraging and time spent foraging at depth for all three prey species. Model output was not highly sensitive to caloric content of prey. For smaller harbor seals, energetic gains were maximized by foraging on Pacific herring or sandlance during normoxia, and sandlance during severe hypoxia. Larger adult harbor seals benefitted most from a herring- or sole-based diet during normoxia, herring and sandlance during moderate to severe hypoxia. The results suggest that shifts in spatial foraging behaviors during hypoxia may be readily apparent upon spatial analysis of TDR data. The information gathered in this thesis will be used in the experimental design of a field-based study of the effects of coastal hypoxia on harbor seal foraging behavior.
