Download or read book Seasonal Movements and Population Trends of Harbor Seals written by Steven J. Jeffries and published by . This book was released on 1986 with total page 41 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 Seasonal Movements and Hauling Site Fidelity of Harbor Seals Phoca Vitulina Richardsi Tagged at the Klamath River California written by Michael J. Herder and published by . This book was released on 1986 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Seasonal Movements and Abundance Dynamics of the Pacific Harbor Seal Phoca Vitulina Richardsi Along the Southern Oregon Coast written by Michael Turner Wilson and published by . This book was released on 1993 with total page 124 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 Assessing Seasonal Trends in Harbor Seal Phoca Vitulina Diet Using Stable Isotope Analysis Along the Whisker written by Justin Arthur Smith and published by . This book was released on 2017 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: Harbor seals (Phoca vitulina) that use tidewater glaciers in the summers to molt, pup, and breed have declined in recent years, which could be attributed to reduced prey availability caused by regime shifts in the coastal marine environment. Recording seasonal dietary trends of harbor seals in different years could improve our ability to test if regime shifts caused these declines. However, such analysis has not been possible, because wild harbor seals are difficult to recapture. Stable isotope analysis of serial sections of growing whiskers (mystacial vibrissae) can be used as a tool to assess diet over different seasons, but uncertainty about whisker growth status and shed dates have prevented accurate estimates of stable isotope deposition date in the past. In Chapter 1, I characterized harbor seal whisker morphology to improve estimates of stable isotope deposition date. First, I measured 567 whiskers collected from wild harbor seals in the Gulf of Alaska from 2003 to 2012. Measurements included the length of a smooth root section (SRS), the length of the bumpy section, and the distance between each bump (inter-bump length; IBL). I found that the SRS was longer for spring-collected whiskers than fall-collected whiskers and matched the length of fully-grown, shed whiskers. These results suggest that the SRS can be used to differentiate whisker shed and growth status, and can be used to determine the sequence of whisker shedding by cohort in summer-captured seals. I also found that the mean IBL was correlated with whisker length and provides a proxy for whisker growth rate. I compared stable carbon isotope ratios along the three longest whiskers from 10 harbor seals and found that intra-individual patterns of whisker stable carbon isotope ratios became more synchronous when expressed by deposition date rather than by position along the whisker. In Chapter 1, I proposed a method to improve deposition date estimates by applying individually adjusted growth rates and better estimates of shed date to wild harbor seal whiskers. In Chapter 2, I analyzed stable isotope ratios from serial sections of whiskers of 32 harbor seals from a population that uses tidewater glacial habitats in southeast Alaska. I used a mixed-effects repeated-measures model to determine the characteristics that influence stable isotope ratios over time. Mean stable carbon and nitrogen isotope ratios differed significantly among size classes (p 0.005), with no effect of sex. Seals were then grouped by size to describe isotopic differences between different demographic groups using Standard Ellipse Corrected Area (SEAc). Larger seals (1.4 m) exhibited a broader isotopic niche in the fall, winter, and spring relative to smaller seals (
Download or read book Fishery Bulletin written by and published by . This book was released on 1993 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oregon Washington Marine Mammal Seabird Surveys written by and published by . This book was released on 1990 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Annual Report of the Marine Mammal Commission written by United States. Marine Mammal Commission and published by . This book was released on 1984 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pupping Phenology Disturbance Movements and Dive Patterns of the Harbor Seal Phoca Vitulina Richardsi Off the Northern San Juan Islands of Washington written by Robert M. Suryan and published by . This book was released on 1995 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book MMS written by and published by . This book was released on 1990 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 White Paper written by Melissa Studer and published by . This book was released on 2000 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Harbor Seal Population Trends and Habitat Use in Maine written by Mary Kathryn Kenney and published by . This book was released on 1994 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seals in Motion written by and published by . This book was released on 2017 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Annual Report to Congress written by United States. Marine Mammal Commission and published by . This book was released on 1993 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:
