Download or read book Pupping Habitat of Grey Seals in the Dutch Wadden Sea written by Sophie Brasseur and published by . This book was released on 2015 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Habitat Quality for Grey Seals in the Dutch Wadden Sea written by Sophie M.J.M. Brasseur and published by . This book was released on 2015 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Recolonization of the Dutch Wadden Sea by the Grey Seal Halichoerus Grypus written by P. J. H. Reijnders and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Common and Grey Seals in the Wadden Sea written by Common Wadden Sea Secretariat. Trilateral Seal Expert Group-plus and published by . This book was released on 2002 with total page 0 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 Common and Grey Seals in the Wadden Sea written by and published by . This book was released on 2002 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gray Seals in Nantucket Sound Massachusetts Winter and Spring 1994 written by Valerie Rough and published by . This book was released on 1995 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Harbour Seal Monitoring and Evaluation for the Luchterduinen Offshore Windfarm written by Sophie Brasseur and published by . This book was released on 2018 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Though it seems unlikely that marine mammals, including seals suffer at a large scale from direct mortality caused by the construction or operation of windfarms at sea, they are likely to be affected by disturbance and habitat alterations.In 2014, Luchterduinen windfarm was constructed in the Dutch coastal zone south west of IJmuiden and the permit (WV/2009-1229) requested monitoring with respect to both harbour and grey seals. Two main questions were formulated:1. How do seals use the coastal zone? The aim was to gain insight in harbour and grey seal movement routes along the Dutch North Sea coastal zone (between the Wadden Sea and the Delta region).2. What is the impact of Luchterduinen on seals? (with a focus on the impact of piling).This rapport discusses the results of the harbour seal studies. The initial monitoring (T0-T1; 2013-2015) based on a series of studies on the movements and habitat use of harbour seals deployed in spring (March), was timed in relation to the construction (2014) and operation of the windfarm. These studies were evaluated after T1 (in 2016). It was concluded that by limiting the study to spring deployments, the harbour seals’ habitat use during a large part of the year was missing. Since harbour seals moult in summer, the trackers attached to the fur typically fell off in June –July. In this study (T2-T3) therefore, a deliberate choice was made to study the behaviour of the seals in the post moult, from September onwards. A total of 18 seals were tracked from September onwards: in 2016 (T2) 6 from the Wadden Sea area and 6 from the Delta and again 6 from the Wadden Sea area in 2017(T3).With longer track durations of 20 to 187 days (mean 106 ± 46 days) in this last study information has been collected covering seven calendar months, six of which had not been studied before in this region. However there was large variation in behaviour, possibly but not solely as a result of the male bias in the sample (11 males, 7 females). Though the maximum and mean distance travelled by the seals was slightly less in autumn, the waters in the study area (i.e. the area off the west coast of the Netherlands enclosed by 51.95°N to 52.94°N, and from the coast offshore to 3.73°E) were used much more extensively by the seals tracked in autumn. In total the seals tracked during T2-T3 spent 27.3% of their time in the defined study area, while during spring deployments for T0-T1, this was only 1.5%. Out of the 18 seals tracked in autumn, 11 were observed in the study area. Interestingly these were animals tagged in the Wadden Sea region. During this time of the year animals are mostly feeding, which probably explains their higher presence in the study area. In contrast, during spring, mostly seals from the Delta crossed the study area en route to their breeding sites in the Wadden Sea. This probably explains the limited amount of time spent in the coastal zone. During the complete Luchterduinen study (T0-T3) comprising of 44 animals in spring and 18 in autumn, only one animal entered the Luchterduinen wind farm area. Its visits were short; which suggests it only crossed the area. Animals tracked during T2-T3 were observed more often in the vicinity of the wind farm, compared to the animals tagged during T0-T1.Based on these studies we concluded that harbour seals use the coastal zone west of North and South Holland to migrate to breeding areas in spring/summer, and use it to feed in autumn and winter. Recently, the recovery of the harbour seals in the Wadden Sea has come to a halt. However, pup production in the Wadden Sea is still increasing, and over two thousand pups are born in the Dutch Wadden Sea each year. Since the population size no longer grows, this suggest that an equal number of individuals die each year. Possibly the population has reached a ‘natural’ carrying capacity. However, human use at sea could also play a role in influencing the survival of individuals and the size of the population. Like other North Sea countries, the Dutch government has shown a clear intention to intensify the use of the marine areas in the near future, for windfarms but also sand mining, traffic and aquaculture. Quite likely this will affect the way the seals use the marine area. Further studies are needed to better understand how habitat changes play a role in the survival of individual animals.
Download or read book Biology of Marine Mammals written by John E. Reynolds and published by Smithsonian Institution. This book was released on 1999-09-17 with total page 589 pages. Available in PDF, EPUB and Kindle. Book excerpt: Taking an integrated approach to the biology of marine carnivores, cetaceans, and sirenians, twenty-two prominent researchers compare marine mammals with one another and with terrestrial mammals, providing a framework for fundamental biological and ecological concepts. They describe functional morphology, sensory systems, energetics, reproduction, communication and cognition, behavior, distribution, population biology, and feeding ecology. They also detail the physiological adaptations—for such activities and processes as diving, thermo-regulation, osmoregulation, and orientation—that enable marine mammals to exploit their aquatic environment.
Download or read book Encyclopedia of Marine Mammals written by William F. Perrin and published by Academic Press. This book was released on 2009-02-26 with total page 1355 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thorough revision of the classic Encyclopedia of Marine Mammals brings this authoritative book right up-to-date. Articles describe every species in detail, based on the very latest taxonomy, and a host of biological, ecological and sociological aspects relating to marine mammals. The latest information on the biology, ecology, anatomy, behavior and interactions with man is provided by a cast of expert authors – all presented in such detail and clarity to support both marine mammal specialists and the serious naturalist. Fully referenced throughout and with a fresh selection of the best color photographs available, the long-awaited second edition remains at the forefront as the go-to reference on marine mammals. - More than 20% NEW MATERIAL includes articles on Climate Change, Pacific White-sided Dolphins, Sociobiology, Habitat Use, Feeding Morphology and more - Over 260 articles on the individual species with topics ranging from anatomy and behavior, to conservation, exploitation and the impact of global climate change on marine mammals - New color illustrations show every species and document topical articles FROM THE FIRST EDITION "This book is so good...a bargain, full of riches...packed with fascinating up to date information. I recommend it unreservedly it to individuals, students, and researchers, as well as libraries." --Richard M. Laws, MARINE MAMMALS SCIENCE "...establishes a solid and satisfying foundation for current study and future exploration" --Ronald J. Shusterman, SCIENCE
Download or read book Bilan de Sant de la Mer Du Nord written by North Sea Task Force and published by Olsen & Olsen. This book was released on 1993 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Grey Seals Halichoerus Grypus in the Dutch North Sea Population Ecology and Effects of Wind Farms written by Sophie M.J.M. Brasseur and published by . This book was released on 2010 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Conservation and Management Plan for the Wadden Sea Seal Population 1996 2000 written by and published by . This book was released on 1996 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fine scale Determinants of Female Grey Seal Halichoerus Grypus Pupping Site and Habitat Preferences at North Rona Scotland written by James Edward Stewart and published by . This book was released on 2013 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract:The grey seal (Halichoerus grypus) is widespread in the Northern Hemisphere and throughout its range hauls out to breed terrestrially on a variety of substrates. A major breeding site in the eastern North Atlantic is the remote island of North Rona, Scotland, which is characterised by undulating grassy terrain, with limited access to the sea, punctuated by irregularly spaced fresh to brackish water pools of variable size. Previous long term research at North Rona has suggested that the distribution of breeding females is influenced by key habitat features including proximity to pools of water and to access from the sea. Using distributional information available for the North Rona colony in conjunction with a set of ecologically relevant environmental predictors within an extensive GIS database, the ecological niche of the grey seal at North Rona was modelled using Ecological Niche Factor Analysis. This was used to determine the distribution of suitable habitat at the North Rona colony and to elucidate the environmental determinants of female pupping site, and subsequent habitat, preferences over multiple years spanning 1998-2010. The environmental predictors utilised were chosen based on the conclusions of previous research. Following the delineation of basic environmental preferences, the influence of social interactions was considered within this modelling approach to further help explain the distribution of pups of various stages. Adult female grey seals show a preference for both pupping sites and subsequent habitat near to pools of water of low salinity at intermediate distances to access points to the sea, though appear to exhibit stronger preferences regarding the characteristics of their habitat than pupping site. It is concluded that these preferences are a result of a requirement for proximity to pools for thermoregulation and for drinking water to avoid a negative water balance. However, females do not typically choose sites directly next to or within pools, this is a result of a trade-off between proximity to pools and proximity to their pup, which is at greater risk when separated from its mother, or close to pools in areas of high adult density. It also appears likely that females choose sites at intermediate proximity to access points as sites directly next to access points experience greater disturbance from other seals arriving to, or leaving, the colony. The widespread availability of apparently suitable habitat suggests that the North Rona colony is not restricted in size by limited availability of suitable pupping sites; other potential drivers of the decline of the North Rona colony are therefore discussed, with recommendations for future research. A parallel analysis investigating pup habitat use showed that weaned pups, unlike neonates, appear to avoid locations near to adult female grey seals. It is concluded that this is a result of social interactions driving weaned pups into areas abandoned, or not yet colonised, by adult females, which are aggressive towards conspecifics during lactation. Overall, the ENFA has provided an excellent means to assess the terrestrial pupping site and subsequent habitat preferences of the grey seal, though alternative approaches are suggested for also assessing social influences on space use.
Download or read book The Effects of Habitat on Population Dynamics in an Expanding Population of Grey Seals Halichoerus Grypus on Muskeget Island MA written by Meagan Sims and published by . This book was released on 2013 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Breeding grey seals (Halichoerus grypus) utilize a variety of terrestrial substrates for parturition, nursing, and mating that vary in topographical characteristics and therefore, the availability of suitable habitat is crucial for the persistence of grey seal populations worldwide. This study compared the effects of habitat type over the course of four breeding seasons on Muskeget Island, Massachusetts within and between years on a suite of population parameters including densities, sex ratios, male harem likelihood and mean harem sizes, pups with and without mothers, nursing events, copulation events, pup mortality, and pup developmental stages. The analysis included the 2007, 2008, 2010, and 2012 breeding seasons and compared two beach and three interior habitat types. I predicted that the predominant pupping habitat type used during the breeding season would be exterior beach types because they were composed of expansive, primarily flat substrate representing the first access points when hauling-out. It was expected that these sites would be the locations used by early arriving females and contain higher densities of all age/sex classes. Areas with higher densities were thought to facilitate a greater number of harems with smaller mean harem sizes, fewer pups with mothers, fewer nursing events, more copulation events, higher pup mortality, and more pups in later developmental stages. Overall, densities for all age/sex classes were significantly higher for exterior open beach and thin beach types compared to interior marsh, back beach grass, and inland types, and the use of interior habitats was higher overall in 2012 than in 2007. Sex ratios became more female biased over the course of the study, and were more heavily femaled biased in interior habitat types. Males were more likely to have harems in open beach types while mean harem sizes were significantly larger in interior habitat types, higher in 2012 than 2007, and significantly positively correlated with adult sex ratios in three out of five habitat types. Densely populated exterior sites had more observed copulation events and pup mortality while no differences in nursing events were found. Additionally, a clear shift in habitat use was evident for the 2010 breeding season for all population parameters. Results suggest the primary use of exterior beach habitats during the initial portion of the breeding season, particularly on the north and west sides of Muskeget, with a progression towards interior habitats throughout the season and the use of interior habitat becoming more prevalent over time. As expected, distinct differences in all population parameters were observed for beach vs. interior habitat use, suggesting habitat type plays a considerable role in the population dynamics of breeding grey seals. To date, little is known regarding this breeding population and this study was the first analysis conducted on Muskeget Island to investigate grey seal pupping habitat choice and its potential effects on population dynamics.
Download or read book Biology of Marine Mammals written by John Elliott Reynolds (III) and published by . This book was released on 1999 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Seal Monitoring and Evaluation for the Luchterduinen Offshore Wind Farm 1 T0 2013 Report written by Roger Kirkwood and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
