Academic literature on the topic 'Seabird conservation'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Seabird conservation.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Seabird conservation"
1
WOLF, S., B. KEITT, A. AGUIRRE-MUÑOZ, B. TERSHY, E. PALACIOS, and D. CROLL. "Transboundary seabird conservation in an important North American marine ecoregion." Environmental Conservation 33, no. 4 (November 1, 2006): 294–305. http://dx.doi.org/10.1017/s0376892906003353.
Full textAbstract:
Many seabird species of conservation concern have large geographic ranges that span political borders, forcing conservation planners to facilitate their protection in multiple countries. Seabird conservation planning within the seabird-diverse California Current System (CCS) marine ecoregion presents an important opportunity for transboundary collaborations to better protect seabirds across the USA/México border. While seabird populations in the USA are relatively well-studied and well-protected, the status of seabird populations in the Mexican region of the CCS is not well known and seabird colonies have been virtually unprotected. This study synthesizes and supplements information on breeding seabird diversity and distribution, identifies and ranks threats to seabirds and evaluates conservation capacity in the Mexican CCS to provide a framework for transboundary seabird conservation throughout the CCS ecoregion. Island-breeding seabirds in México support 43–57% of CCS breeding individuals, 59% of CCS breeding taxa and a high level of endemism. Connectivity between populations in México and the USA is high. At least 17 of the 22 extant Mexican CCS breeding seabirds are USA/México transboundary breeders or foragers, 13 of which are federally listed in the USA or México. Introduced predators and human disturbance have caused multiple seabird population extirpations in the Mexican CCS because breeding colonies lack legal protection or enforcement. However, conservation capacity in this region has increased rapidly in recent years through the establishment of new protected areas, growth of local conservation non-governmental organizations, and increase in local community support, all of which will allow for more effective use of conservation funds. Transboundary conservation coordination would better protect CCS seabirds by facilitating restoration of seabird colonies in the Mexican CCS and enabling an ecoregion-wide prioritization of seabird conservation targets to direct funding bodies to the most cost-effective investments.
2
Heswall, Ariel-Micaiah, Lynn Miller, Ellery J. McNaughton, Amy L. Brunton-Martin, Kristal E. Cain, Megan R. Friesen, and Anne C. Gaskett. "Artificial light at night correlates with seabird groundings: mapping city lights near a seabird breeding hotspot." PeerJ 10 (October 18, 2022): e14237. http://dx.doi.org/10.7717/peerj.14237.
Full textAbstract:
Artificial light at night (ALAN) is a growing conservation concern for seabirds, which can become disoriented and grounded by lights from buildings, bridges and boats. Many fledgling seabirds, especially Procellariiformes such as petrels and shearwaters, are susceptible to light pollution. The Hauraki Gulf, a seabird hotspot located near Tāmaki Makaurau/Auckland, Aotearoa—New Zealand’s largest urban city, with a considerable amount of light pollution and regularly documented events of seabird groundings. We aim to identify the characteristics of locations especially prone to seabird groundings. We used an online database of seabirds taken to a wildlife rescue facility by the public to map 3 years of seabird groundings and test for correlations between seabird groundings and the natural night sky brightness. We found that areas with lower amounts of natural night sky brightness and greater light pollution often had a higher number of seabirds grounded. Further, we identified important seasonal patterns and species differences in groundings. Such differences may be a by-product of species ecology, visual ecology and breeding locations, all of which may influence attraction to lights. In general, seabird groundings correlate with the brightness of the area and are species-specific. Groundings may not be indicative of human or seabird population abundance considering some areas have a lower human population with high light levels and had high amounts of seabird groundings. These findings can be applied worldwide to mitigate groundings by searching and targeting specific brightly lit anthropogenic structures. Those targeted structures and areas can then be the focus of light mitigation efforts to reduce seabird groundings. Finally, this study illustrates how a combination of community science, and a concern for seabirds grounded from light attraction, in addition to detailed animal welfare data and natural night sky brightness data can be a powerful, collaborative tool to aid global conservation efforts for highly-at-risk animals such as seabirds.
3
Borrelle, Stephanie B., Philipp H. Boersch-Supan, Chris P. Gaskin, and David R. Towns. "Influences on recovery of seabirds on islands where invasive predators have been eradicated, with a focus on Procellariiformes." Oryx 52, no. 2 (December 19, 2016): 346–58. http://dx.doi.org/10.1017/s0030605316000880.
Full textAbstract:
AbstractProtecting seabirds is a global conservation priority given that 29% of seabird species are threatened with extinction. One of the most acute threats to seabirds is the presence of introduced predators, which depredate seabirds at all life stages, from eggs to adults. Consequently, eradication of invasive predators has been identified as an effective and commonly used approach to seabird conservation. Seabird recovery following the eradication of predators is influenced by complex and interacting environmental and demographic factors, and there are gaps in our understanding of species-specific responses. We reflect on the recovery of seabirds on islands cleared of predators, drawing on the equilibrium theory of island biogeography, and synthesize key influences on recovery reported in the literature. We present a regionally specific case study on the recovery of seabird colonies (n = 98) in the Hauraki Gulf, New Zealand, which is a hotspot of seabird diversity (27 species), with a long history of eradications of invasive predators. We found that on islands cleared of predators seabirds recover over time, and such islands have more diverse seabird assemblages than islands that never had predators. Recovery appears to be influenced by a suite of site- and species-specific factors. Managers may assume that given enough time following eradication of predators, seabirds will recolonize an island. Although time is a factor, proximity to source populations and human activities has a significant effect on recolonization by seabirds, as do demographic traits, colonizing ability and habitat suitability. Therefore, integrating expected site and species-specific recovery responses in the planning of eradications should help guide post-eradication management actions.
4
Mínguez, Eduardo, Daniel Oro, Eduardo De Juana, and Alejandro Martínez-Abraín. "Mediterranean seabird conservation: what can we do?" Scientia Marina 67, S2 (July 30, 2003): 3–6. http://dx.doi.org/10.3989/scimar.2003.67s23.
Full text
5
Suazo, Cristián G., Roberto P. Schlatter, Aldo M. Arriagada, Luis A. Cabezas, and Jaime Ojeda. "Fishermen's perceptions of interactions between seabirds and artisanal fisheries in the Chonos archipelago, Chilean Patagonia." Oryx 47, no. 2 (April 2013): 184–89. http://dx.doi.org/10.1017/s0030605311001815.
Full textAbstract:
AbstractInteractions between seabirds and commercial fishing activities have been well documented but little information is available regarding the impacts of more traditional fishing practices on seabird populations. We interviewed fishermen, administered questionnaires, and made field-based observations to determine the extent to which artisanal fisheries interact with and affect seabirds in the fjords and channels of the Chonos archipelago in southern Chile. Our surveys indicated a positive perception of seabirds as useful indicators of marine productivity and in their role scavenging fish waste and discards associated with fishing operations. However, the surveys also revealed that fishermen routinely establish seasonal camps for collecting seabird eggs and adults for food or bait and introduce feral predators to seabird breeding colonies on islands. Understanding the traditional practices of fishermen is critical for the future of community-based conservation of the region's marine resources and biodiversity.
6
Yorio, Pablo, Esteban Frere, Patricia Gandini, and William Conway. "Status and conservation of seabirds breeding in Argentina." Bird Conservation International 9, no. 4 (December 1999): 299–314. http://dx.doi.org/10.1017/s0959270900003506.
Full textAbstract:
SummaryWe present information on the current population status of seabirds that breed along the Patagonian coast obtained between 1993 and 1995. A total of 16 species, including two penguins, one petrel, five cormorants, three gulls, three terns and two skuas, breed along the 3,400-km coast from southern Buenos Aires (38°58'S) to Tierra del Fuego (54°50'S). Breeding seabirds are not as abundant in coastal Argentina as was previously thought. Eleven of the 16 species have less than 5,000 pairs. The most abundant seabird is the Magellanic PenguinSpheniscus magellanicuswith 964,000 pairs, an order of magnitude higher than all other species. As well as Magellanic Penguins, Kelp GullsLarus dominicanus, and Imperial CormorantsPhalacrocorax atricepsare relatively abundant and have a wide distribution. Other seabirds, such as Red-legged Cormorants P.gaimardi, Olrog's GullsL. atlanticus, and Dolphin Gulls L.scoresbii, have a highly restricted distribution or nest in small colonies at a few sites in Argentina. The Patagonian coast is one of the most pristine coastal ecosystems in the world and, thus far, few seabirds are seriously threatened. However, oil pollution and commercial fisheries are having a negative impact on some seabirds and some colonies have shown recent declines. Current threats and impacts, including pollution, fisheries, human disturbance, guano harvesting, and introduction of alien species are discussed. There are currently 34 protected coastal areas, although in many cases protection measures are not adequately enforced and some areas with high seabird diversity and abundance still lack legal and effective protection. Conservation actions and requirements, including direct actions, monitoring and research are suggested.
7
Groff, Dulcinea V., Kit M. Hamley, Trevor J. R. Lessard, Kayla E. Greenawalt, Moriaki Yasuhara, Paul Brickle, and Jacquelyn L. Gill. "Seabird establishment during regional cooling drove a terrestrial ecosystem shift 5000 years ago." Science Advances 6, no. 43 (October 2020): eabb2788. http://dx.doi.org/10.1126/sciadv.abb2788.
Full textAbstract:
The coastal tussac (Poa flabellata) grasslands of the Falkland Islands are a critical seabird breeding habitat but have been drastically reduced by grazing and erosion. Meanwhile, the sensitivity of seabirds and tussac to climate change is unknown because of a lack of long-term records in the South Atlantic. Our 14,000-year multiproxy record reveals an ecosystem state shift following seabird establishment 5000 years ago, as marine-derived nutrients from guano facilitated tussac establishment, peat productivity, and increased fire. Seabird arrival coincided with regional cooling, suggesting that the Falkland Islands are a cold-climate refugium. Conservation efforts focusing on tussac restoration should include this terrestrial-marine linkage, although a warming Southern Ocean calls into question the long-term viability of the Falkland Islands as habitat for low-latitude seabirds.
8
Hata, Kenji, Mari Kohri, Sayaka Morita, and Syuntaro Hiradate. "Fine-scale distribution of aboveground biomass of herbaceous vegetation and soil nutrients on an oceanic island after goat eradication are correlated with grazing damage and seabird nesting." Pacific Conservation Biology 20, no. 4 (2014): 344. http://dx.doi.org/10.1071/pc140344.
Full textAbstract:
We tested whether vegetation recovery on an oceanic island after the eradication of feral goats is related to disturbances by goats and recovery of seabird nesting in an island. To test, we investigated relationships among the aboveground biomass of herbaceous vegetation, nutrient concentrations in the soil after goat eradication, and vegetation degradation before goat eradication and seabird nesting after the eradication. The investigation was conducted on the island of Nakoudojima, a subtropical island situated in the northwestern Pacific Ocean with consideration of fine-scale variation of topography and structure of current vegetation. The aboveground biomass of herbaceous vegetation was correlated with the presence of vegetation degradation before goat eradication but not with seabird nesting after eradication. Concentrations of carbon and nitrogen in the soil were correlated with both the presence of vegetation degradation and seabird nesting. The concentration of available phosphorus in the soil was correlated with nesting seabirds but not with vegetation degradation. The presence of nesting seabirds was correlated with differences in dominant species in the vegetation after goat eradication and with topography. Our results suggested that fine-scale heterogeneities of the aboveground biomass of herbaceous vegetation and the concentrations of nutrients in the soil after goat eradication in an island could be related to vegetation degradation and subsequent erosion of surface soil caused by goats and seabird nesting after the goat eradication.
9
Le Bot, Tangi, Amélie Lescroël, and David Grémillet. "A toolkit to study seabird–fishery interactions." ICES Journal of Marine Science 75, no. 5 (April 2, 2018): 1513–25. http://dx.doi.org/10.1093/icesjms/fsy038.
Full textAbstract:
Abstract Seabirds and fisheries have been interacting from ancient times, sometimes with mutual benefits: Seabirds provided fishermen with visual cues of fish aggregations, and also fed upon food subsids generated by fishing activities. Yet fisheries and seabirds may also compete for the same resources, and their interactions can lead to additional seabird mortality through accidental bycatch and diminishing fishing efficiency, threatening vulnerable seabird populations. Understanding these complex relationships is essential for conservation strategies, also because it could enhance and ease discussion between stakeholders, towards a common vision for marine ecosystem management. As an aid in this process, we reviewed 510 scientific publications dedicated to seabirds–fisheries interactions, and compiled a methodological toolkit. Methods employed therein serve four main purposes: (i) Implementing distribution overlap analyses, to highlight areas of encounter between seabirds and fisheries (ii) Analysing movement and behavioural patterns using finer-scale information, to characterize interaction types (iii) Investigating individual-scale feeding ecology, to assess fisheries impacts at the scale of bird populations, and (iv) Quantifying the impacts of seabird–fishery interactions on seabird demography and population trends. This latter step allows determining thresholds and tipping points with respect to ecological sustainability. Overall, we stress that forthcoming studies should integrate those multiple approaches, in order to identify and promote best practices towards ecosystem-based fisheries management and ecologically sound marine spatial planning.
10
Grecian, W. James, Matthew J. Witt, Martin J. Attrill, Stuart Bearhop, Peter H. Becker, Carsten Egevang, Robert W. Furness, et al. "Seabird diversity hotspot linked to ocean productivity in the Canary Current Large Marine Ecosystem." Biology Letters 12, no. 8 (August 2016): 20160024. http://dx.doi.org/10.1098/rsbl.2016.0024.
Full textAbstract:
Upwelling regions are highly productive habitats targeted by wide-ranging marine predators and industrial fisheries. In this study, we track the migratory movements of eight seabird species from across the Atlantic; quantify overlap with the Canary Current Large Marine Ecosystem (CCLME) and determine the habitat characteristics that drive this association. Our results indicate the CCLME is a biodiversity hotspot for migratory seabirds; all tracked species and more than 70% of individuals used this upwelling region. Relative species richness peaked in areas where sea surface temperature averaged between 15 and 20°C, and correlated positively with chlorophyll a , revealing the optimum conditions driving bottom-up trophic effects for seabirds. Marine vertebrates are not confined by international boundaries, making conservation challenging. However, by linking diversity to ocean productivity, our research reveals the significance of the CCLME for seabird populations from across the Atlantic, making it a priority for conservation action.
Dissertations / Theses on the topic "Seabird conservation"
1
Rollinson, Dominic Paul. "Understanding and mitigating seabird bycatch in the South African pelagic longline fishery." Doctoral thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/25500.
Full textAbstract:
Seabirds are considered one of the most threatened groups of birds in the world. They face additional mortality both on their breeding islands from introduced predators and at sea by fishing fleets, as fisheries bycatch, as well as other human impacts. Seabird bycatch has negatively affected many seabird populations worldwide, with trawl, gillnet and longline fisheries considered the most destructive to seabird populations. Seabird bycatch from trawl and gillnet fisheries has been significantly reduced in recent years, but large numbers of seabirds are still killed annually by longline fisheries. Of the two types of longline fisheries (demersal and pelagic), pelagic longlining is considered the most harmful to seabirds as lines remain closer to the surface for longer periods than demersal longlining, and it is harder to weight lines to ensure rapid sinking beyond the depth they are accessible to birds. Seabirds are killed when they swallow baited hooks and consequently drown. Despite the large number of studies investigating seabird bycatch from pelagic longline fisheries, there remain gaps in our understanding of seabird bycatch from pelagic longline fisheries. This thesis addresses some of these knowledge gaps and makes recommendations as to how seabird bycatch from pelagic longliners can be reduced at both a local and global scale. Chapters 2 and 3 investigate the factors affecting seabird bycatch from pelagic longliners off South Africa, provide a summary of seabird bycatch from the fishery for the period 2006–2013 and quantify the structure of seabird assemblages associated with pelagic longline vessels off South Africa. This was achieved by analysing seabird bycatch data collected by fisheries observers as well as data from sea trials onboard pelagic longliners. Seabird bycatch by pelagic longliners off South Africa over the 8-year study period has been significantly reduced from the 8-year period (1998–2005), mainly driven by a significant reduction in seabird bycatch rates from foreign-flagged vessels, which are responsible for c. 80% of fishing effort off South Africa. Seabird bycatch rates from South African vessels still remain high, four times higher than the interim national target of < 0.05 birds per 1000 hooks. The species composition of seabird bycatch off South Africa is best explained by an understanding of the structure of the seabird assemblage associated with longline vessels. For most species, bycatch and attendance ratios were similar, but for some species such as shy-type and black-browed albatrosses there were large mismatches, likely caused by differences in foraging behaviour and foraging dominance hierarchies. In Chapters 4 and 5 the foraging ecology of the most commonly recorded bycatch species off South Africa, the white-chinned petrel (Procellaria aequinoctialis), is investigated. An understanding of the foraging ecology of commonly recorded bycatch species enhances our understanding of seabird bycatch and helps to improve the design of current and future mitigation measures. The year-round movements of white-chinned petrels from Marion Island were investigated with Global Location Sensors (GLS loggers) and GPS loggers. Adult white-chinned petrels undertake only limited east-west movements of, with all birds remaining between southern Africa and Antarctica. These results strengthen the theory that there is limited spatial overlap year-round between white-chinned petrel populations from South Georgia, the southern Indian Ocean islands and New Zealand sub-Antarctic islands, suggesting that these populations can be managed as separate stocks. The diving behaviour of white-chinned and grey petrels (P. cinerea), another common bycatch species in Southern Ocean longline fleets, were examined with the use of temperature-depth recorders (TDRs), deployed on birds from Marion Island and Gough Island. My study was the first to analyse TDR dive data from any Procellaria petrel, and recorded them reaching maximum dive depths of 16 and 22 m, respectively. Current best practise suggests that baited hooks be protected to a depth of 5 m by bird-scaring lines, but my results suggest this depth should be increased to at least 10 m. Although line weighting is a proven mitigation measure to reduce seabird bycatch from pelagic longliners, fishers have concerns that it will compromise fish catches, crew safety and operational efficiency. In Chapter 6 I analyse line weighting data from trials onboard three pelagic longline vessels, to address the concerns of fishermen. My results show that sliding leads can be incorporated into pelagic longline fisheries without compromising fish catch, crew safety or operational efficiency. I thus recommend that sliding leads be used on pelagic longline vessels fishing off South Africa. By incorporating studies investigating the factors affecting seabird bycatch, seabird foraging ecology and the efficacy of seabird bycatch mitigation measures, my thesis has broadened our understating of seabird bycatch from pelagic longliners and makes meaningful recommendations to further reduce bycatch, both locally and globally. Although seabird bycatch rates have declined off South Africa, through the use of a number different mitigation measures, they still remain higher than the South African national target and thus more work is needed to achieve this target. To reduce seabird bycatch from pelagic longliners to acceptable levels, studies from the world's various longline fleets needs to be considered and improved upon, with seabird conservationists and fishermen working together to achieve this goal.
2
Gaglio, Davide. "Investigating the foraging ecology and energy requirements of a seabird population increasing in an intensely exploited marine environment." Doctoral thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/27020.
Full textAbstract:
Their high energetic demands make seabirds sensitive to changes in prey availability, which is often reflected in their diet and energetic expenditure during breeding. Populations of the three seabirds endemic to southern Africa's Benguela upwelling ecosystem that rely on small pelagic fish have decreased dramatically over the last decade. In contrast, the population of the greater crested tern Thalasseus bergii has increased. To understand these conflicting trends, I investigated the foraging ecology and energy requirements of greater crested tern breeding in the Western Cape, South Africa. Diet was assessed by a novel non-invasive methodology developed in this study, using digital photography. More than 24,000 prey items from at least 51 different prey taxa were identified, with 34 new prey species recorded, revealing a high degree of foraging plasticity for this seabird. Greater crested terns rely mainly on anchovy Engraulis encrasicolus (65%), which averaged 84 mm long. Prey composition differed significantly between breeding stages, with anchovy especially dominant at the onset of the breeding period and the diet becoming more variable as the season progressed. Time-energy models for breeding terns were built based on activity budgets collected from non-invasive video-recordings and focal observations. Foraging trips were significantly longer during incubation than the chick provisioning stages, and feeding rates doubled from early to late chick provisioning. This study illustrated a steady increase in energy needs of adults throughout the breeding season, due to their increased foraging effort to meet chick energy needs. In comparison to other Benguela endemic seabirds that also rely on small pelagic fish, terns displayed substantially lower energy requirements at both individual and population levels. I also explored the benefits underlying interactions within mixed-species aggregations by investigating the costs induced by kleptoparasitism between mixed colonies of greater crested terns and Hartlaub's gulls Chroicocephalus hartlaubii and colonies with greater crested terns alone. Video-recordings coupled with focal observations showed that terns suffer direct costs to chick provisioning rates and indirect costs through energy expenditure in a mixed-species colony, suggesting that these breeding assemblages may be a form of parasitism rather than a mutualistic association. Despite the detrimental effects of interspecific kleptoparasitism, the marked foraging plasticity and low energetic requirements of greater crested terns, described in this study, coupled with specific life history traits such as low fidelity to breeding sites and extended post-fledging care, are key factors that allow this species to cope with changes in the availability and abundance of their main prey. Understanding species-specific behavioural responses to ecosystem variations in the Benguela upwelling system is vital for assessing the impact of commercial fisheries on seabird populations and fish stocks. Finally, the implementation of the method developed in this study, in long-term monitoring programmes, may provide crucial knowledge for conservation plans and key input to realising an ecosystem approach to fisheries management.
3
Sawyer, Thomas R. "Habitat use and breeding performance in an inshore foraging seabird, the Black Guillemot Cepphus grylle." Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312131.
Full text
4
Montrond, Gilson. "Assessing sea turtle, seabird and shark bycatch in artisanal, semi-industrial and industrial of fisheries in the Cabo Verde Archipelago." Master's thesis, Faculty of Science, 2021. http://hdl.handle.net/11427/32854.
Full textAbstract:
Firstly, I am very grateful to Birdlife International for the MSc scholarship. I am also very grateful to Professor Peter Ryan of the FitzPatrick Institute of African Ornithology, University of Cape Town, for agreeing to supervise this project and for his guidance, insights and comments on the write-up. I am grateful to Sarah Saldanha, for all the support during this MSc. Many thanks also to Dr Ross Wanless, Dr Rima Jabado and Ruben Rocha for all support, guidance and advice. I want to thank a lot Andy Angel for their accommodation and all support in South Africa. I am grateful to all the UCT staff and BirdLife Senegal Staff for all the support during this study. Many thanks to my family for all the encouragement and support. I want to thank to all the Cabo Verde fishers for their willingness to share their knowledge and experience. Finally, many thanks to the Conservation Biology class of 2019, for all their support.
5
Nupen, Lisa Jane. "A conservation genetic study of threatened, endemic southern African seabirds." Doctoral thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/13387.
Full textAbstract:
Includes bibliographical references.Molecular techniques have a broad, and growing, application in the field of wildlife conservation, ranging from the systematic identification and classification of taxa, through studying genetic connectivity between populations, to parentage and individual barcoding. While they are applied to a wide range of spatial- and temporal-scales, molecular approaches complement traditional methods used to classify, investigate and understand the natural world. This study uses multiple lines of evidence, at various scales, to investigate how seabird biology influences population-level responses to changing environments. The focal area is the Agulhas-Benguela Ecosystem (ABE) along the south-western coast of Africa. Globally, biodiversity loss due to environmental change in marine ecosystems is significantly affecting the phenology, distribution, dispersal patterns, and demographic rates of organisms across trophic-levels. Broad-scale changes are occurring that have consequences for both commercial fisheries and threatened marine top-predators. Seabirds are valuable indicators of the state of marine ecosystems, and changes in their distribution and dispersal patterns may reflect those of species in lower trophic-levels. This is the case in the ABE, where some endemic seabird species are better at responding to changes in their environment than others. Twentieth century shifts in the distribution of key pelagic prey species in the ABE have had serious consequences for endemic seabirds. The African Penguin Spheniscus demersus, Cape _ Gannet Moms capensis and Cape Cormorant Phalacrocorax capensis rely on these pelagic fish, and all three species are threatened and in decline. In this study population genetic and phylogeographic methods are used to: (i) quantify levels of genetic diversity, and determine regional-scale structure within all three focal species; (ii) explore fine-scale population structure in African Penguin; and (iii) compare wild and captive populations of African Penguins. The conservation of genetic diversity is essential for the long-term persistence of species. Population genetics can help us to understand the evolutionary processes that have shaped patterns of genetic diversity in the focal species, and predict how they might respond to further environmental changes. Comparative phylogeography, combined with capture-mark- recapture models based on ringing data and annual census counts, provide the most complete picture of the micro-evolutionary forces at play in this unique ecosystem, and highlight seabird life-history characteristics may facilitate adaptation and survival under novel conditions. This is the first conservation genetic study of endemic seabirds in the ABE. Although the three focal species differ in a number of aspects of their breeding and foraging ecology, and in some life-history characteristics, they have evolved under similar selective pressures across their shared range, and represent natural replicates that allow us to determine the dominant drivers of population genetic change. Flexibility in foraging behaviour and the degree of breeding site fidelity exhibited by each of the three focal species affect the rate and effectiveness of their demographic responses to changes in their environment. Understanding connectivity among seabird populations is crucial for their long-term conservation, and has been investigated in numerous studies of seabird species from around the world. Similar to many of these, this study found very low levels of genetic structure among populations of all three focal species based on DNA sequence data, suggesting long-term gene-flow among them, despite potential physical and non-physical barriers. Overall, the patterns observed suggest that high connectivity characterises their breeding regions, and most breeding colonies, buffering the respective populations against environmental variability. These results were supported by fine-scale analyses of the African Penguin using microsatellite markers that also suggested high levels of gene-flow, which may have masked genetic signatures of the regional- and colony-level bottlenecks experienced by this species. Microsatellite-based genetic diversity and fine-scale structure were also compared among wild and captive populations of African Penguins to assess the genetic consequences of a planned conservation breeding program. The genetic composition of birds in captivity largely reflects that found in wild populations. The success of reintroduction in terms of decreasing extinction risk in the wild is uncertain, and should be implemented as part of a broader management plan that addresses the primary threats to wild populations. Further research is required to improve our understanding of many aspects of endemic southern African marine avifauna and better inform our ability to ensure their continued persistence in this system.
6
Rice, Edward. "Rory lines : silver lining for seabirds in South Africa's demersal trawl fisheries." Master's thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/10902.
Full textAbstract:
Includes bibliographical references.Seabird bycatch in commercial fisheries is one of the major factors causing decreases in many seabird populations. In trawl fisheries, high mortalities have been recorded as a result of seabirds being struck by trawl warps (the cables used to tow the trawl net). Tori (bird-scaring) lines have been used to decrease seabird mortality in some trawl fisheries by up to 90%. However, tori lines are not effective at reducing the number of birds that drift towards the trawl warps while feeding on factory discards alongside the vessel. The Albatross Task Force (ATF) helped to develop and test a new device, the Rory Line (RL), to be used in conjunction with tori lines, and designed to reduce warp strikes by placing a physical barrier between the scupper (where factory discards are released) and the danger zone (where the trawl warps enter the water) at the stern of the vessel. This study tests the efficacy of the RL at reducing the number of birds drifting into the danger zone and the number of birds being struck by the trawl warps.
7
Votier, Stephen C. "Conservation implications of variation in diet and dietary specialisation in great skuas." Thesis, University of Glasgow, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390768.
Full text
8
Martínez, Abraín Alejandro. "Research applied to the Conservation of Seabirds Breeding on Islands of the Western Mediterranean." Doctoral thesis, Universitat de Barcelona, 2003. http://hdl.handle.net/10803/779.
Full textAbstract:
This thesis includes several research works on population dynamics and conservation of seabirds in two small islands of the western Mediterranean: the Columbretes Islands (Castellón) and the island of Benidorm (Alicante). Most of the works included in the thesis report have been already published in scientific journals. This thesis includes both works discussing the role of certain biological factors (Section I) on seabird population dynamics and assessing the effects of human activities (Section II) on population numbers. Each section is preceded by an introductory chapter dealing, in a more informal manner, with the topic approached by that section. Section I approaches specifically the influence of immigration and environmental stochasticity on the population dynamics of shags Phalacrocorax aristotelis (Chapter 1), the role of philopatry and conspecific atraction in breeding site selection in Audouin's gull Larus audouinii (Chapter 2), the determinants of colony-site dynamics in Audouin's gull (Chapter 3), the movements of yellow-legged gulls Larus michahellis from the Mediterranean to the Atlantic (Chapter 4), the presence of immigrant Cory's shearwaters Calonectris diomedea from Atlantic colonies in Mediterranean colonies (Chapter 5). Section II includes works discussing the role of landfills in disease dispersal among yellow-legged gulls (Chapter 6), the role of discards of the trawling fishing fleet as a food source during the summer for gulls (Chapter 7), the role of fishing discards on the dynamics of a colony of Audouin's gull facing local extinction (Chapter 8) and the impact of tourism on a small colony of the Eleonora's falcon Falco eleonorae (Chapter 9). A number of conclusions are listed. Basically we found that adult survival is the demographic parameter with the largest impact on the growth rate of colonies, although transfer processes play a very important role as well since seabirds are structured in subpopulations (patches) separated in space. Human activities can affect all demographic parameters (fecundity/mortality and immigration/emigration) and must be taken into account to understand seabird dynamics, specially fishing activities which may even produce the local extinction of colonies. Past is also a factor to be taken into account since present-day dynamics result from the interplay between local, regional and historical factors. Most of the seabird colonies in the Mediterranean are small sized and hence prone to genetic erosion and stochasticity besides being composed by species and subspecies with a high degree of endemism. Colonies not occupied at present must also be included in conservation plans since seabirds have high dispersal capabilities. Finally, the tremendous importance of the social factor in seabird colonies can be used as an effective conservation tool.
9
Grecian, William James. "Factors influencing the marine spatial ecology of seabirds : implications for theory, conservation and management." Thesis, University of Plymouth, 2011. http://hdl.handle.net/10026.1/873.
Full textAbstract:
Seabirds are wide-ranging apex-predators and useful bio-indicators of marine systems. Nevertheless, changes are occurring in the marine environment, and seabirds require protection from the deleterious effects of climate change, fisheries, pollution, offshore development, introduced predators and invasive species. The UK supports internationally important populations of seabirds but also has vast wind and wave resources, therefore understanding how seabirds use the marine environment is vital in order to quantify the potential consequences of further exploiting these resources. In this thesis I first describe the range of wave energy converting devices operational or in development in the UK, and review the potential threats and benefits these developments may have for marine birds. I then synthesise data from colony-based surveys with detailed information on population dynamics, foraging ecology and near-colony behaviour, to develop a projection model that identifies important at-sea areas for breeding seabirds. These models show a positive spatial correlation with one of the most intensive at-sea seabird survey datasets, and provide qualitatively similar findings to existing tracking data. This approach has the potential to identify overlap with offshore energy developments, and could be developed to suit a range of species or whole communities and provide a theoretical framework for the study of factors such as colony size regulation. The non-breeding period is a key element of the annual cycle of seabirds and conditions experienced during one season may carry-over to influence the next. Understanding behaviour throughout the annual cycle has implications for both ecological theory and conservation. Bio-logging can provide detailed information on movements away from breeding colonies, and the analysis of stable isotope ratios in body tissues can provide information on foraging during the non-breeding period. I combine these two approaches to describe the migration strategies of northern gannets Morus bassanus breeding at two colonies in the north-west Atlantic, revealing a high degree of both winter site fidelity and dietary consistency between years. These migratory strategies also have carry-over effects with consequences for both body condition and timing of arrival on the breeding grounds. Finally, I investigate the threats posed to seabirds and other marine predators during the non-breeding period by collating information on the distributions of five different species of apex predator wintering in the Northwest African upwelling region. I describe the threat of over-fishing and fisheries bycatch to marine vertebrates in this region, and highlight the need for pelagic marine protected areas to adequately protect migratory animals throughout the annual cycle. In summary, the combination of colony-based studies, bio-logging, stable isotope analysis and modelling techniques can provide a comprehensive understanding of the interactions between individuals and the marine environment over multiple spatial and temporal scales.
10
Clay, Thomas Anthony. "Drivers of variation in the migration and foraging strategies of pelagic seabirds." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/267809.
Full textAbstract:
The ability to move and forage efficiently plays a major role in determining the fate of individuals, and has important implications for population dynamics and ecosystem functioning. Migration is a particular type of movement strategy, whereby animals may travel remarkable distances in order to take advantage of seasonality in resource availability or to avoid arduous winter conditions; however, this can be at a cost in terms of increased mortality. Indeed, anthropogenic threats in non-breeding areas are a major cause of population declines and a better understanding of non-breeding spatial ecology is required in order to advance both ecological theory and conservation management. The recent development of animal tracking technologies, in particular light-based geolocation, has made it possible to track large-scale and long-term movements; however, there are still gaps in our knowledge, such as the links between migratory and reproductive performance, connectivity among populations and the ontogeny of migration strategies. In this thesis, I utilise multi-species and longitudinal datasets from albatrosses and petrels, some of the most mobile species on Earth, to explore the drivers of variation in movements, habitat use and foraging behaviour, and the implications for life history and conservation. In Chapter 1, I provide an overview of the key topics of this thesis. In Chapter 2, I provide quantitative recommendations of minimum sample sizes needed to track pelagic seabird migrations, using data from 10 species. In Chapter 3, I examine between- and within-population differences in the habitat preferences and distributions of albatrosses, including the relative roles of habitat specialization and intra-specific competition. In Chapter 4, I investigate the year-round movement and foraging strategies of petrels living in nutrient-poor environments. In Chapter 5, I examine potential links between foraging behaviour during the non-breeding season and reproductive senescence. In Chapter 6, I explore the ontogeny of foraging behaviour and foraging site fidelity in young albatrosses, shedding light on their “lost years” at sea. Finally, I conclude with a general discussion summarizing main findings and suggesting future work. Overall, my results highlight the complex relationships among individual traits, the environment, movements and foraging behaviour, and population dynamics across the lifespan of individuals, with implications for the conservation of this highly threatened group of species.
Books on the topic "Seabird conservation"
1
1, U. S. Fish and Wildlife Service Region. Regional seabird conservation plan. Portland, OR (911 NE 11th Ave., Portland, 97232): U.S. Fish and Wildlife Service, Migratory Birds and Habitat Programs, 2005.
Find full text
2
Seabird islands: Ecology, invasion, and restoration. Oxford: Oxford University Press, 2011.
Find full text
3
Mulder, Christa P. H. Seabird islands: Ecology, invasion, and restoration. Oxford: Oxford University Press, 2011.
Find full text
4
Melvin, Edward F. Seabird avoidance measures for small Alaskan longline vessels. Seattle, Wash: University of Washington, Washington Sea Grant Program, 2006.
Find full text
5
W, Kress Stephen, ed. Giving back to the earth: A teacher's guide to Project Puffin and other seabird studies. Gardiner, Me: Tilbury House, 1997.
Find full text
6
Exxon Valdez Oil Spill Seabird Restoration Workshop (1995 Girdwood, Alaska). Exxon Valdez oil spill restoration project 95038 final report: Exxon Valdez Oil Spill Seabird Restoration Workshop. [Seattle, WA]: Pacific Seabird Group, 1997.
Find full text
7
Seabird Specialist Group Workshop (1990 Hamilton, New Zealand). Seabirds on islands: Threats, case studies and action plans : proceedings of the Seabird Specialist Group Workshop held at the XX World Conference of the International Council for Bird Preservation, University of Waikato, Hamilton, New Zealand, 19-20 November 1990. Cambridge, U.K: BirdLife International, 1994.
Find full text
8
Seabirds of Hawaii: Natural history and conservation. Ithaca, N.Y: Comstock Pub. Associates, 1990.
Find full text
9
Pierce, Raymond J. Surveys and capacity building in Kiritimati (Christmas Island, Kiribati), June 2007, to assist in restoration of populations of bokikokiko and seabirds. Onerahi, N.Z: Eco Oceania, 2007.
Find full text
10
FAO/Birdlife South American Workshop on Implementation of NPOA-Seabirds and Conservation of Albatrosses and Petrels. Report of the FAO/Birdlife South American Workshop on Implementation of NPOA-Seabirds and Conservation of Albatrosses and Petrels: Valdivia, Chile, 2-6 December 2003. Rome: Food and Agriculture Organization of the United Nations, 2004.
Find full textBook chapters on the topic "Seabird conservation"
1
Furness, R. W., and P. Monaghan. "Seabird Conservation Requirements." In Seabird Ecology, 139–47. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4613-2093-7_8.
Full text
2
Jodice, Patrick G. R., and Robert M. Suryan. "The Transboundary Nature of Seabird Ecology." In Landscape-scale Conservation Planning, 139–65. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-9575-6_8.
Full text
3
Gouveia, Cátia S. A. "Light Pollution as a Seabirds' Conservation Threat." In Seabird Biodiversity and Human Activities, 213–23. Boca Raton: CRC Press, 2022. http://dx.doi.org/10.1201/9781003047520-17.
Full text
4
Pereira, Jorge M., Vitor H. Paiva, Lucas Krüger, and Stephen C. Votier. "Tracking Seabirds for Conservation and Marine Spatial Planning." In Seabird Biodiversity and Human Activities, 59–74. Boca Raton: CRC Press, 2022. http://dx.doi.org/10.1201/9781003047520-5.
Full text
5
Sultana, Joe. "Seabird Conservation Problems in the Maltese Islands." In Mediterranean Marine Avifauna, 423–29. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-70895-4_25.
Full text
6
Blanchard, Kathleen A., and David N. Nettleship. "Education and Seabird Conservation: A Conceptual Framework." In Wildlife 2001: Populations, 616–32. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2868-1_45.
Full text
7
Oliveira, Paulo, Félix M. Medina, Manuel Nogales, and Pedro Luís Geraldes. "Eradication and Control of Invasive Mammal Species as a Seabird Conservation Tool." In Seabird Biodiversity and Human Activities, 224–42. Boca Raton: CRC Press, 2022. http://dx.doi.org/10.1201/9781003047520-18.
Full text
8
Parrish, Julia K., Kate Litle, Jane Dolliver, Todd Hass, Hillary K. Burgess, Erika Frost, Charlie W. Wright, and Timothy Jones. "Defining the baseline and tracking change in seabird populations." In Citizen Science for Coastal and Marine Conservation, 19–38. Abingdon, Oxon : Routledge, 2017. | Series: Earthscan oceans: Routledge, 2017. http://dx.doi.org/10.4324/9781315638966-2.
Full text
9
Gallo-Cajiao, Eduardo, Evan Hamman, and Bradley K. Woodworth. "The international institutional framework for seabird conservation in the South Pacific." In Environmental Law and Governance in the Pacific, 93–123. Abingdon, Oxon ; New York, NY : Routledge, 2020.: Routledge, 2020. http://dx.doi.org/10.4324/9780429260896-9.
Full text
10
Garthe, Stefan. "Identification of areas of seabird concentrations in the German North Sea and Baltic Sea using aerial and ship-based surveys." In Progress in Marine Conservation in Europe, 225–38. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/3-540-33291-x_14.
Full textConference papers on the topic "Seabird conservation"
1
Karreman, Annelise, Jeremy Leggoe, Terry Griffiths, Lisa King, and Nino Fogliani. "Hydrodynamic Forces on Subsea Pipelines due to Orbital Wave Effects." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-10647.
Full textAbstract:
Ensuring pipeline stability is a fundamental aspect of subsea pipeline design and can contribute a significant proportion of project costs in regions with large diameter trunklines, shallow water and severe geotechnical and metocean conditions [1]. Reducing the conservatism and simplifications of existing pipeline stabilisation design methods therefore offers economic benefits to hydrocarbon producers necessary to ensure the ongoing viability of projects in these regions. To realise this potential and reduce the conservatism of the existing design methods, a more accurate understanding of the hydrodynamic loads exerted by waves and currents is required. This paper investigates one of the inherent assumptions incorporated into the existing design methods through the arrangement of previous experimental investigations to determine whether rectilinear motion provides a reasonable approximation to simulate the near seabed orbital particle paths in wind-generated waves. This assumption is based on the flattening of particle paths to ellipsoids with depth and ignores the small vertical velocity components near the seabed. Based on the hydrodynamic forces calculated numerically using a validated Computational Fluid Dynamics (CFD) model for rectilinear and orbital wave modelling it is concluded that pipeline stabilisation requirements calculated in accordance with the DNV-RP-F109 absolute lateral static stability design method and rectilinear wave motion assumption are conservative. It is also concluded that the hydrodynamic force asymmetry in favour of the reverse half wave cycle caused by the vertical velocity components in orbital wave conditions requires further consideration to determine the implication for dynamic lateral stability design methods.
2
Liu, Ming-ming, Ming Zhao, and Lin Lu. "Numerical Investigation of Local Scour Around Submerged Pipeline in Shoaling Conditions." In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-78440.
Full textAbstract:
Water waves play an important role in local scour around subsea pipelines laid on the sandy seabed, especially in shallow water regions. In this paper, a two-dimensional numerical model is employed to predict local scour around submarine pipelines under water waves in shoaling condition. The motion of water under waves is simulated by solving the Reynolds Averaged Navier-Stokes (RANS) equations. The evolution of the seabed surface near the pipeline is predicted by solving the conservation of the sediment mass, which transport in the water in the forms of bed load and suspended load. The main aim of this study is to investigate the effect of the seabed slope on the scour profiles and scour depth. To achieve this aim, numerical simulations of scour around a pipeline on a flat seabed and on a slope seabed with a slope angle of 15° are conducted for various wave conditions.
3
Smith, Russell, Tommie Carr, and Michael Lane. "Computational Tool for the Dynamic Analysis of Flexible Risers Incorporating Bending Hysteresis." In ASME 2007 26th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2007. http://dx.doi.org/10.1115/omae2007-29276.
Full textAbstract:
Non-bonded flexible-pipe risers provide a structurally compliant solution in offshore floating production systems for the recovery of oil & gas. The bending stiffness of the flexible pipe is an important property in designing the riser system to safely withstand extreme and fatigue loading conditions. These risers have two fundamentally different bending stiffness properties that depend on if the riser system is pressurized or depressurized. A depressurized riser has a comparatively small linear bending stiffness. Most riser designs apply this stiffness as its produces conservative (large) bending responses. In recent years, the bending response predicted from the depressurized bending stiffness has proven overly conservative and there has been an increasing demand to consider the larger hysteretic bending stiffness of the pressurized riser. The objective is to reduce the conservatism and achieve an approved safe design. Recent developments have advanced the modeling of flexible riser bending with hysteresis and this capability has now been incorporated into an industry standard finite-element riser analysis tool. This paper describes the background of hysteresis in relation to non-bonded flexible pipes and outlines the methodology of the riser motions software that incorporates bending stiffness with hysteresis. Riser systems where the dynamic bending response is critical to the success of the design are the main applications that will benefit from this new technology. Examples include: i.) The dynamic bending response at the seabed touchdown of a deepwater catenary riser. ii.) Bending at an interface with the riser hang-off or subsea tie-in.
4
Griffiths, Terry, Scott Draper, Liang Cheng, Feifei Tong, Antonino Fogliani, David White, Fraser Johnson, Daniel Coles, Stephen Ingham, and Caroline Lourie. "Subsea Cable Stability on Rocky Seabeds: Comparison of Field Observations Against Conventional and Novel Design Methods." In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-77130.
Full textAbstract:
As offshore renewable energy projects progress from concept demonstration to commercial-scale developments there is a need for improved approaches beyond conventional cable engineering design methods that have evolved from larger diameter pipelines for the oil and gas industry. New approaches are needed to capture the relevant physics for small diameter cables on rocky seabeds to reduce the costs and risks of power transmission and increase operational reliability. This paper reports on subsea cables that MeyGen installed for Phase 1a of the Pentland Firth Inner Sound tidal stream energy project. These cables are located on rocky seabeds in an area where severe metocean conditions occur. ROV field observation of these cables shows them to be stable on the seabed with little or no movement occurring over almost all of the cable routes, despite conventional engineering methods predicting significant dynamic movement. We cite recent research undertaken by the University of Western Australia (UWA) to more accurately assess the hydrodynamic forces and geotechnical interaction of cables on rocky seabeds. We quantify the conformity between the cables and the undulating rocky seabed, and the distributions of cable-seabed contact and spanning via simulations of the centimetric-scale seabed bathymetry. This analysis leads to calculated profiles of lift, drag and seabed friction along the cable, which show that all of these load and reaction components are modelled in an over-conservative way by conventional pipeline engineering techniques. Overall, our analysis highlights that current cable stability design can be unnecessarily conservative on rocky seabeds. Our work foreshadows a new design approach that offers more efficient cable design to reduce project capex and enhance through-life integrity management.
5
Christensen, Erik Damgaard, Stefan Carstensen, Mikael Thyge Madsen, Peter Allerød Hesselbjerg, and Christel Jeanty Nielsen. "Pore Pressure Under a Gravity Based Structure Under the Influence of Waves." In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-62585.
Full textAbstract:
The total wave load on a gravity based foundation for offshore wind turbines is influenced by the pore pressure from beneath the structure. The pore pressure is induced by the wave-structure-seabed interaction. Often the uplift force is included in a simplified way in the design of the gravity based foundation. This leads typically to very conservative designs in order to accommodate the uncertainties in the procedure. The experiments shall lead to better prediction models based on for instance CFD model’s with the direct calculation of pressure variations in the seabed and any erosion protection layer. Herewith, it will be possible to get a direct assessment of wave loads on the foundation, also under the seabed level. The study includes experiments as well as numerical analyses. A good agreement between the experimental results and the numerical analyses was found. In the numerical analyses, it was possible to investigate the effect of air content in the pores, which turned out to have an effect on the distribution of the pore pressure.
6
Igland, Ragnar T., and Tore So̸reide. "Advanced Pipeline Trawl Gear Impact Design." In ASME 2008 27th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/omae2008-57354.
Full textAbstract:
Non-linear dynamic finite element analysis for the interference between clump weight and pipeline on seabed is performed using ANSYS software package, Ref /1/. Output from the analysis is the pull-over force magnitude, as well as shape and duration of impact on pipeline from the clump weight. Two pipelines sizes are analysed for trawl pull-over, the 10" and 12" pipelines laying on seabed. Small scale tests have been used to verify the FE model. The dynamic behaviour during impact testing is fairly well simulated by FE analysis scheme chosen. The results from the FE analysis are compared with the recommended practise outlined by DNV-RP-F111. Realistic trawl pull-over loads are established using actual stiffness of the pipeline and the pipe-soil interaction. The reduced trawl loads and the effect of pipe-soil interaction lead to reduced load effects and will avoid a conservative design and reduce the intervention costs.
7
Besedin, Dmitry, Ralf Peek, Sze Yu Ang, Knut Vedeld, Olav Fyrileiv, and Alexey Gulyaev. "Effects of Correlation Between Waves and Currents on Pipeline Free Span VIV Fatigue: A Case Study." In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-77455.
Full textAbstract:
In shallow waters, subsea pipelines can suffer fatigue damage from Vortex Induced Vibrations (VIV) by the combined effects of waves and currents. A full characterization of the joint probability distribution of waves and currents involves at least 5 variables, 2 for currents (magnitude and direction), and 3 for waves (significant wave height, mean wave direction, and wave period at the peak of the spectrum). In lieu of sufficient data to adequately characterize the associated joint probability density function, DNV GL in their “Recommended Practice” propose an approximation: Assume that the direction of current and wave effects is always the same, but for a given direction, waves and currents are assumed statistically independent. In this paper 28 years of hindcast data are used to test the accuracy of this colinearity approximation in the Sea of Okhotsk. Rather than attempting to estimate a joint probability density function in 5 variables, the span fatigue assessment is simply performed for the entire 28 years of the hindcast database to obtain an average rate of fatigue damage. It is found that this history-based approach can lead to fatigue damage rates that are much higher than those derived from the colinearity assumption. This non-conservatism of the colinearity assumption, arises for pipeline orientations for which both waves and currents can contribute strongly to the VIV response without being exactly colinear. It is concluded that caution is needed in using the colinearity assumption, but an update of the span assessment procedure should also address issues for which current assessment procedures are conservative, such as seabed proximity and trench effects, nonlinearity in the pipe-soil interaction, and the change in axial forces due to transverse displacements of the pipe, which are expected under extreme combined current and wave conditions, as envisioned on on-bottom stability design criteria.
8
Pontaza, Juan P., and Raghu G. Menon. "On the Numerical Simulation of Fluid-Structure Interaction to Estimate the Fatigue Life of Subsea Pipeline Spans: Effects of Wall Proximity." In ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/omae2010-20804.
Full textAbstract:
Subsea pipelines laid on uneven terrain typically have segments of unsupported spans, referred to as “free spans”. Alternatively, subsea pipelines lying on loose and fine gravel or sand may develop free spans due to sea bottom being scoured out due to current action. This paper is concerned with the numerical simulation of fluid-structure interaction (FSI) to predict the response of free spans exposed to sea bottom currents. When exposed to sea bottom currents these spans may experience vortex-induced vibrations (VIV), which may cause fatigue damage to the pipeline. The VIV response of the pipe span is predicted by coupling a three-dimensional viscous incompressible Navier-Stokes solver with a nonlinear beam finite element solver. Parameters such as turbulence in the flow, proximity of the seabed, pipe sagging due to submerged weight, and pipe-soil interaction, are all accounted for in the FSI simulation. We pay special attention to the effect of seabed / wall proximity on VIV. Design guidelines for free spans are typically based on VIV amplitude and frequency responses for isolated pipes, with little regard to effects of seabed / wall proximity. This may result in overly conservative designs and/or expensive span remediation recommendations, when in reality no span remediation is required. Two examples of field applications are presented.
9
Odina, Lanre, and Roger Tan. "Seismic Fault Displacement of Buried Pipelines Using Continuum Finite Element Methods." In ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79739.
Full textAbstract:
In deep waters, pipelines are usually installed exposed on the seabed, as burial is generally not required to ensure on-bottom stability. These exposed pipelines are nevertheless susceptible to seismic geohazards like slope instability at scarp crossings, soil liquefaction and fault movements which may result in failure events, although larger diameter pipelines are generally known to have good tolerances to ground deformation phenomena, provided the seismic magnitudes are not too onerous. Regardless of the pipeline size, these seismic geohazard issues are usually addressed during the design stage by routing the pipeline to avoid such hazardous conditions, where possible. However, extreme environmental conditions like hurricanes or tropical cyclones, which are typically experienced in the Gulf of Mexico and Asia-Pacific regions, are also factors which can cause exposed pipelines to be susceptible to large pipeline displacements and damage. Secondary stabilisation in the form of rock dump is sometimes employed to reduce the hydrodynamic loads from high turbidity currents acting on the pipeline. However, rock dumping (or burying the displaced pipeline) on a fault line could again pose a threat to its integrity following a seismic faulting event. The traditional method of assessment of a buried pipeline subjected to seismic faulting is initially carried out using analytical methods. Due to the limitations of these techniques for large deformation soil movement associated with fault displacement, non-linear finite element (FE) methods are widely used to assess the pipeline integrity. The FE analysis typically idealises the pipeline using discrete structural beam-type elements and the pipeline-soil interaction as discrete non-linear springs, based on the concept of subgrade reactions proposed by Winkler. Recent research from offshore pipeline design activities in the arctic environment for ice gouge events have however suggested that the use of the discrete Winkler element model leads to over-conservative results in comparison to the coupled continuum model. The principal reason for the conservatism is related to the poor modeling of realistic surrounding soil behaviour for large deformation events. This paper discusses the application of continuum FE methods to model the fully coupled seabed-buried pipeline interaction events subject to ground movements at active seismic faults. Using the continuum approach, a more realistic mechanical response of the pipeline is established and can be further utilised to confirm that calculated strains are within allowable limits.
10
Boeck, Florin, Matthias Golz, Sebastian Ritz, and Gerd Holbach. "Automated Landing and Mooring in Deep-Sea Environment Using Suction Buckets for Unmanned Vehicles." In ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/omae2016-54830.
Full textAbstract:
Autonomous underwater vehicles (AUVs) depend primarily on electrical power. Monitoring the deep-sea ocean floor efficiently requires easily accessible recharging techniques. In contrast to conservative ship-dependent charging processes on the surface, the Subsea Monitoring via Intelligent Swarms (SMIS) consortium uses a seabed station (SBS) as a power supply for AUVs. This paper describes the fully automated secure landing procedure of the SBS followed by a ground mooring maneuver on sandy sediments or soft clays. The unmanned seabed station is equipped with various sensors for status detection and environmental observation. In order to control the freefall and grounding without endangering the valuable components, an innovative procedure was implemented. Once landed, the nearly buoyancy-neutral station is moored using down-scaled suctions buckets that are normally used in immobile offshore oil rig foundations. Laboratory full-scale experiments in modified test tanks for different length-to-diameter ratios endorse the design process. The feasibility of landing, mooring and ascending techniques was proven in field-tests in the Baltic Sea and the Atlantic Ocean.
Reports on the topic "Seabird conservation"
1
Tegan Carpenter-Kling, Tegan Carpenter-Kling. Tracking non-breeding endangered Benguela seabirds to inform conservation strategies. Experiment, October 2021. http://dx.doi.org/10.18258/22139.
Full text