Download or read book Atmospheric and Oceanographic Effects on Grey Seal Halichoerus Grypus and Harbour Seal Phoca Vitulina Haul out Behaviour in Findhorn Bay written by Felicity Johnson and published by . This book was released on 2016 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Environmental and Biotic Influences on the Haulout Behavior of Phoca Vitulina Linnaeus 1758 and Halichoerus Grypus Fabricius 1791 written by Clarence Edward Button and published by . This book was released on 1973 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hauling Out Behaviour of Harbour Seals Phoca Vitulina Richardsi with Particular Attention to Thermal Constraints written by Peter Watts and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 1991 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gray Halichoerus Grypus and Harbor Seal Phoca Vitulina Bycatch and Depredation in New England Sink gillnet Fisheries written by Laura N. Sirak and published by . This book was released on 2015 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine mammals interact with commercial fisheries via competition for resources, depredation (feeding on fish caught in gear), entanglement, and bycatch in fishing gear. In New England, gray seals (Halichoerus grypus) and harbor seals (Phoca vitulina) are often taken as bycatch in sink-gillnet fisheries and are believed to depredate fish in gillnets. As seal populations increase, interactions with fisheries are also likely to increase, affecting both seal stocks and the New England fishing industry. This study aims to understand seal bycatch in the New England sink-gillnet fisheries by identifying the spatial and temporal trends in bycatch as well as the characteristics of seals that are taken most frequently as bycatch. Depredation is also a concern in the commercial fishing industry, however, there is some controversy among fishermen and scientists concerning the identification of the species responsible for depredation (e.g. seal vs. spiny dogfish (Squalus acanthias)). Therefore, a protocol for identifying seal and spiny dogfish depredation was developed and used to identify depredation in a small-scale study of the sink-gillnet fishery targeting skate. Data from the Northeast Fisheries Observer Program (NEFOP) from 2005-2013 were analyzed to assess seal bycatch in the Northeast sink-gillnet fishery. Male seals were taken significantly more frequently than females, with young of the year most commonly occurring as bycatch. Areas where seals were taken in New England shifted seasonally, generally following the annual life history of each seal species. Gray seal bycatch showed an increasing trend over the years of study, with highest bycatch occurring in the spring in areas closest to haul out sites: Muskeget and Monomy Island, MA, USA. Harbor seal bycatch was much more variable between years, with highest bycatch occurring in the winter near major harbor seals haul out sites along the southern Maine coast and southeastern Massachusetts. This study was a crucial step to understanding the complexities of seal-fishery interactions in New England. In order to mitigate damage from depredation, it is important to know the source of the damage. Characteristics of seal and spiny dogfish bites were identified using foam imprints from jaws and bites by captive animals in the soft tissue of fish. Measurements from bite imprints and damaged fish were used to develop a protocol for identifying damage in the field. In general, dogfish bites were clean (flesh completely removed), circular in shape, and wider than long (bite ratio (bite length/bite width) 0.6), whereas seal bites were ragged (flesh not completely removed, but partially torn from the bite), retangular or trapezoidal in shape, and usually longer than wide or equal in length and width (bite ratio 0.7). This protocol was used to identify damaged catch observed on a commercial gill-net fishing vessel targeting skate in New England waters June - August 2014. In this small-scale study, dogfish bites were identified as the damage source significantly more frequently than seal bites (Multifactor ANOVA: F [subscript, degree of freedom]=2,66 = 9.306, p=0.0003; Tukey HSD: p
Download or read book Harbour Seal Phoca Vitulina and Grey Seal Halichoerus Grypus Abundance in the St Lawrence Estuary written by Maurice Lamontagne Institute and published by . This book was released on 1995 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: An aerial survey and several boat surveys were conducted during April-September 1994 to obtain information on harbour and grey seal abundance and distribution in the Saint-Lawrence Estuary. A total of 389 harbour seals and 111 grey seals were counted on or near haul-out sites during the aerial survey flown in August.
Download or read book The effects of human disturbance on the behaviour of common seals Phoca vitulina and grey seals Halichoerus grypus on Blakeney Point North Norfolk written by E S S. HAMILTON and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Grey Seal Halichoerus Grypus Haul out Pattern and Behavioural Response to Environmental Variables and Anthropogenic Disturbances on Puffin Island North Wales written by Claire Louise Bass and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Distribution and Counts of Harbour Phoca Vitulina and Grey Seals Halichoerus Grypus on the Atlantic Coast of Nova Scotia and Bay of Fundy from Aerial and Land Surveys 2019 2021 written by Damian Lidgard and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Our knowledge of the summer abundance and distribution of harbour and grey seals in eastern Canada is limited due to lack of surveys. Between 2019 and 2021, land and aerial surveys were conducted to determine the size and distribution of harbour and grey seal haulouts along the Atlantic coast of Nova Scotia (NS) and Bay of Fundy and in the Bras D'Or Lake, NS"--Abstract.
Download or read book Sources of Variability in Aerial Survey Counts of Harbour Seals on Haul out Sites in the Bay of Fundy written by G. Mark Fowler and published by Dartmouth, N.S. : Fisheries and Ocean Canada. This book was released on 2005 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiple aerial censuses were conducted of a major harbour seal (Phoca vitulina) haulout area off Grand Manan, New Brunswick, Canada, during the molting period to quantify sources of variability in aerial survey counts. Counts increased and decreased with local time, with peak counts between 1200-1600 EST. Low tide may have functioned as a delimiter to this relationship by degree of emergence of haul-out sites, assuming competition for space between seals, but the apparent effect could be an alias for cumulative survey disturbance or progression through the molt period. Hot days appeared to depress counts. Standard deviations of counts made between 1200-1600, computed independently for each day to negate tide or disturbance effects, ranged from 3.7 to 7.5% of the mean. We estimated the proportion of seals in the water during peak haul-out at 20% of the opulation. Photographic counts usually exceeded visual counts, but the difference extended to counts of small groups of animals unlikely to have been visually miscounted. The results (visual counts) of the aerial census study were used to derive correction factors for seals in the water and time of day. These correction factors were applied to earlier estimates of total Bay of Fundy area harbour seal abundance derived from aerial surveys in 1986 and 1992 (adjusted abundances of 2 362 and 4 218 harbour seals respectively). The earlier surveys were also used to adjust the 1995 study to provide a total abundance estimate for the Bay of Fundy (5446 harbour seals). A growth curve fitted to the three point estimates for 1986, 1992 and 1995 suggested abundance increased at a rate of 9.3% per year
Download or read book Movements and Home Ranges of Harbor Seals Phoca Vitulina in the Inland Waters of the Pacific Northwest written by Sarah E. Hardee and published by . This book was released on 2008 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book IN SITU MEASUREMENTS BY INSTRUMENTED GREY SEALS HALICHOERUS GRYPUS REVEAL FINE SCALE OCEANOGRAPHIC PROPERTIES AND ENVIRONMENTAL INFLUENCES ON MOVEMENT PATTERNS written by Bernadette Nowak and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The influence of oceanographic conditions on the movements of large marine predators has been demonstrated in diverse taxa. However, obtaining subsurface data that are spatio-temporally relevant to the decisions made by benthically-foraging species can be challenging. Between the years 2009 and 2015, 117 grey seals (Halichoerus grypus) were captured on Sable Island, NS and instrumented with Mk10-AF FastlocTM GPS devices. A bio-optical model for the estimation of chlorophyll-a using light attenuation was developed by performing a replicated experiment in the Bedford Basin. This model was applied to data collected in situ by grey seals and, along with other oceanographic conditions, mapped across the Scotian Shelf, providing high spatio-temporal coverage. Behavioural states were estimated from location data using the hidden Markov movement model. Generalized linear mixed-effects models indicated that grey seal behaviours are influenced by the fine-scale chlorophyll-a and environmental conditions they encounter across the oceanographically heterogeneous Scotian Shelf.
Download or read book Influence of Sex and Body Mass on Harbor Seal Phoca Vitulina Diving Behavior written by Alexandra Sasha McFarland and published by . This book was released on 2013 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Counts and Spatial Distribution of Harbour Seals Phoca Vitulina and Grey Seals Halichoerus Grypus from an Aerial Survey of the Coast of the Newfoundland Shelf and Sandwich Bay Labrador During the Summer of 2021 written by Charmain D. Hamilton and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Harbour seals reside throughout the year around Newfoundland and Labrador (NL) at unknown abundance levels. The first systematic survey for harbour seals occurred along the NL Shelf during July and August 2021 to obtain haul-out counts and assess distribution. Grey seals were also recorded as these two species can share haul-out locations. Photographic surveys were flown along the coastline with a Bell 429 helicopter. 3,341 seals were seen hauled out and identified as harbour, grey or unknown seals. After the unknown seals were assigned to species, 2,961 harbour and 380 grey seals were estimated to be seen. The largest numbers of harbour seals were found in the Grey Islands, Saint Pierre and Miquelon (France) and along the southern coast of Newfoundland east of Bay d'Espoir. Grey seals were only observed hauled out in southern Newfoundland, primarily west of Placentia Bay. No seals were seen hauled out in Sandwich Bay, Labrador. Despite differences in methodology compared to previous work, the results indicate that harbour seals have disappeared from previously occupied areas. Although increases have probably occurred in some areas, this species has likely not regained the abundance levels present before the bounty hunt (1952-1976). Future surveys are needed to understand regional population trends and gain a better understanding of counts and distribution in Labrador"--Abstract, page iv.
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 Habitat Use Haul out Behaviour and Site Fidelity of Grey Seals Halichoerus Grypus Along the Ceredigion Marine Heritage Coast Wales written by Kate Michelle Lewis and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Human Exposure on the Anti predatory Response of Harbor Seals Phoca Vitulina written by Jennifer Kathryn Olson and published by . This book was released on 2013 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Environmental and Biological Factors that Influence Harbor Seal Phoca Vitulina Richardsi Haulout Behavior in Washington and Their Consequences for the Design of Population Surveys written by Jennifer Moss and published by . This book was released on 1992 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:
