862 research outputs found
Natural history contributions of the University of Glasgow Exploration Society to Scotland and the World
Expeditions with a natural history focus have been
organised by University of Glasgow staff and
students since the 1930s. The educational benefits of
such expeditions to students have been reported by
Harper
et
al.
(
Journal
of
Biological
Education
51, 3-
16; 2017). Here, we present a short history of these
expeditions, concentrating on their scientific
achievements. In addition to expedition reports, a
large number of PhD theses, masters and honours
project reports and scientific papers have been
based on expedition work. Many biological
specimens have been deposited in museums,
including some new species. We provide case
histories of four expedition locations, to demonstrate
the variety of work done, and the value of returning
many times to the same place: Scotland, Trinidad and
Tobago, North Cyprus and Ecuador. A major problem
for expeditions is funding. For many years, the
Carnegie Trust for the Universities of Scotland ran a
funding stream that was crucial to the viability of
Scottish university expeditions, but this has sadly
now closed. For Glasgow University expeditions, the
Blodwen Lloyd Binns Bequest has provided a reliable
source since 1994, and we hope that it will continue
to do so
Unravelling migratory connectivity in marine turtles using multiple methods
Comprehensive knowledge of the fundamental spatial ecology of marine species is critical to allow the identification of key habitats and the likely sources of anthropogenic threats, thus informing effective conservation strategies.
2.âResearch on migratory marine vertebrates has lagged behind many similar terrestrial animal groups, but studies using electronic tagging systems and molecular techniques offer great insights.
3.âMarine turtles have complex life history patterns, spanning wide spatio-temporal scales. As a result of this multidimensional complexity, and despite extensive effort, there are no populations for which a truly holistic understanding of the spatial aspects of the life history has been attained. There is a particular lack of information regarding the distribution and habitats utilized during the first few years of life.
4.âWe used satellite tracking technology to track individual turtles following nesting at the green turtle Chelonia mydas nesting colony at PoilĂŁo Island, Guinea Bissau; the largest breeding aggregation in the eastern Atlantic.
5.âWe further contextualize these data with pan-Atlantic molecular data and oceanographic current modelling to gain insights into likely dispersal patterns of hatchlings and small pelagic juveniles.
6.âAll adult turtles remained in the waters of West Africa, with strong connectivity demonstrated with Banc DâArguin, Mauritania.
7.âDespite shortcomings in current molecular markers, we demonstrate evidence for profound sub-structuring of marine turtle stocks across the Atlantic; with a high likelihood based on oceanographic modelling that most turtles from Guinea-Bissau are found in the eastern Atlantic.
8.âSynthesis and applications. There is an increased need for a better understanding of spatial distribution of marine vertebrates demonstrating life histories with spatio-temporal complexity. We propose the synergistic use of the technologies and modelling used here as a working framework for the future rapid elucidation of the range and likely key habitats used by the different life stages from such species
Climate change resilience of a globally important sea turtle nesting population
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordFew studies have looked into climate change resilience of populations of wild animals. We use a model higher vertebrate, the green sea turtle, as its life history is fundamentally affected by climatic conditions, including temperature-dependent sex determination and obligate use of beaches subject to sea level rise (SLR). We use empirical data from a globally important population in West Africa to assess resistance to climate change within a quantitative framework. We project 200Â years of primary sex ratios (1900â2100) and create a digital elevation model of the nesting beach to estimate impacts of projected SLR. Primary sex ratio is currently almost balanced, with 52% of hatchlings produced being female. Under IPCC models, we predict: (a) an increase in the proportion of females by 2100 to 76%â93%, but cooler temperatures, both at the end of the nesting season and in shaded areas, will guarantee male hatchling production; (b) IPCC SLR scenarios will lead to 33.4%â43.0% loss of the current nesting area; (c) climate change will contribute to population growth through population feminization, with 32%â64% more nesting females expected by 2120; (d) as incubation temperatures approach lethal levels, however, the population will cease growing and start to decline. Taken together with other factors (degree of foraging plasticity, rookery size and trajectory, and prevailing threats), this nesting population should resist climate change until 2100, and the availability of spatial and temporal microrefugia indicates potential for resilience to predicted impacts, through the evolution of nest site selection or changes in nesting phenology. This represents the most comprehensive assessment to date of climate change resilience of a marine reptile using the most up-to-date IPCC models, appraising the impacts of temperature and SLR, integrated with additional ecological and demographic parameters. We suggest this as a framework for other populations, species and taxa.Portuguese Foundation for Science and TechnologyMAVA FoundationRufford Foundatio
Small-scale fisheries of Peru: a major sink for marine turtles in the Pacific
1. Over the last few decades, evidence of marine vertebrate bycatch has been collected for a range of industrial fisheries. It has recently been acknowledged that large impacts may also result from similar interactions with small-scale fisheries (SSF) due largely to their diffuse effort and large number of vessels in operation. Marine mammals, seabirds, turtles as well as some shark species have been reported as being impacted by SSF worldwide.
2. From 2000 to 2007, we used both shore-based and onboard observer programmes from three SSF ports in Peru to assess the impact on marine turtles of small-scale longline, bottom set nets and driftnet fisheries.
3. We reported a total of 807 sea turtles captured, 91Ă8% of which were released alive. For these three sites alone, we estimated c. 5900 turtles captured annually (3200 loggerhead turtles Caretta caretta, 2400 green turtles Chelonia mydas, 240 olive ridleys Lepidochelys olivacea and 70 leatherback turtles Dermochelys coriacea).
4. SSF in Peru are widespread and numerous (\u3e100 ports, \u3e9500 vessels, \u3e37 000 fishers), and our observed effort constituted c. 1% of longline and net deployments. We suggest that the number of turtles captured per year is likely to be in the tens of thousands. Thus, the impacts of Peruvian SSF have the potential to severely impact sea turtles in the Pacific especially green, loggerhead and leatherback turtles.
5. Implications of the human use of turtle products as âmarine bushmeatâ are also raised as an important issue. Although such utilization is illegal, it is difficult to foresee how it can be managed without addressing the constraints to the livelihoods of those depending almost entirely on coastal resources.
6. Syntheses and applications. Our analysis demonstrates that, despite logistical challenges, it is feasible to estimate the bycatch per unit of effort in SSF by combining methods that account for fishing effort and bycatch, such as using onboard and shore-based observers. We highlight sea turtle bycatch in SSF in the southeast Pacific as a major conservation concern but also suggest possible paths for mitigation
The importance of passive integrated transponder (PIT) tags for measuring life-history traits of sea turtles
Capture-mark-recapture studies rely on the identification of individuals through time, using markers or tags, which are assumed to be retained. This assumption, however, may be violated, having implications for population models. In sea turtles, individual identification is typically based on external flipper tags, which can be combined with internal passive integrated transponder (PIT) tags. Despite the extensive use of flipper tags, few studies have modelled tag loss using continuous functions. Using a 26-year dataset for sympatrically nesting green (Chelonia mydas) and loggerhead (Caretta caretta) turtles, this study aims to assess how PIT tag use increases the accuracy of estimates of life-history traits. The addition of PIT tags improved female identification: between 2000 and 2017, 53% of green turtles and 29% of loggerhead turtles were identified from PIT tags alone. We found flipper and PIT tag losses were best described by decreasing logistic curves with lower asymptotes. Excluding PIT tags from our dataset led to underestimation of flipper tag loss, reproductive periodicity, reproductive longevity and annual survival, and overestimation of female abundance and recruitment for both species. This shows the importance of PIT tags in improving the accuracy of estimates of life-history traits. Thus, estimates where tag loss has not been corrected for should be interpreted with caution and could bias IUCN Red List assessments. As such, long-term population monitoring programmes should aim to estimate tag loss and assess the impact of loss on life-history estimates, to provide robust estimates without which population models and stock assessments cannot be derived accurately
Green turtles highlight connectivity across a regional marine protected area network in west Africa
Networks of marine protected areas (MPAs) are invaluable for the protection of species
with high dispersal capacity, yet connectivity within networks is poorly understood. We
demonstrate the connectivity within the regional MPA network in West Africa (RAMPAO),
mediated by the largest green turtle population in the eastern Atlantic Ocean. We
equipped with satellite tags 45 female green turtles nesting in the BijagoÌ
s Archipelago,
Guinea-Bissau, and tracked them during internesting, migration, and foraging to quantify
the degree of coverage the RAMPAO network provides during each of these critical
periods. During the internesting period, turtles were largely concentrated around the
nesting islands, with a mean of 94.8% (SD 0.1%, range: 46% - 100%, n = 40 turtles) of
tracking positions falling within MPA limits. Among the 35 turtles successfully tracked into
the foraging period, we identified variable migratory strategies, with 12 turtles remaining
near-resident at distances of 40-90 km from breeding sites, 10 turtles migrating 300-400
km to The Gambia and Senegal, and 13 turtles traveling >1000 km to northern Mauritania.
Of the 35 foraging turtles, 26 used MPAs, with a mean of 78.0% (SD 34.8%, range: 3.7% -
100%) of their tracking positions falling within the limits of RAMPAO MPAs, across
Guinea-Bissau, Senegal and Mauritania. Migration corridors with high concentrations of
passing turtles were mostly located nearshore, and 21% of these high passage areas fell
within the MPA network. Overall, we found that this population connects five RAMPAO
MPAs, yet some foraging sites (e.g., in the BijagoÌ
s) and important migration areas (e.g.,
Cap-Vert peninsula) described here are currently unprotected. These results are relevant
to any considerations of MPA extension or establishment within the regional network,
which would contribute towards meeting the Convention on Biological Diversity targets for
national marine protected area estate coverage. By documenting biological connectivity
across RAMPAO, this study represents an important example of the relevance of
international protected area networks for green turtle conservation and for wider
conservation action at a regional scale.Fundação para a CiĂȘncia e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio
Multinational tagging efforts illustrate regional scale of distribution and threats for east pacific green turtles (Chelonia mydas agassizii).
Published onlineJournal ArticleResearch Support, Non-U.S. Gov'tThis is the final version of the article. Available from Public Library of Science via the DOI in this record.To further describe movement patterns and distribution of East Pacific green turtles (Chelonia mydas agassizii) and to determine threat levels for this species within the Eastern Pacific. In order to do this we combined published data from existing flipper tagging and early satellite tracking studies with data from an additional 12 satellite tracked green turtles (1996-2006). Three of these were tracked from their foraging grounds in the Gulf of California along the east coast of the Baja California peninsula to their breeding grounds in MichoacĂĄn (1337-2928 km). In addition, three post-nesting females were satellite tracked from Colola beach, MichoacĂĄn to their foraging grounds in southern Mexico and Central America (941.3-3020 km). A further six turtles were tracked in the Gulf of California within their foraging grounds giving insights into the scale of ranging behaviour. Turtles undertaking long-distance migrations showed a tendency to follow the coastline. Turtles tracked within foraging grounds showed that foraging individuals typically ranged up to 691.6 km (maximum) from release site location. Additionally, we carried out threat analysis (using the cumulative global human impact in the Eastern Pacific) clustering pre-existing satellite tracking studies from Galapagos, Costa Rica, and data obtained from this study; this indicated that turtles foraging and nesting in Central American waters are subject to the highest anthropogenic impact. Considering that turtles from all three rookeries were found to migrate towards Central America, it is highly important to implement conservation plans in Central American coastal areas to ensure the survival of the remaining green turtles in the Eastern Pacific. Finally, by combining satellite tracking data from this and previous studies, and data of tag returns we created the best available distributional patterns for this particular sea turtle species, which emphasized that conservation measures in key areas may have positive consequences on a regional scale.The work was supported by Earthwatch Institute, David and Lucile Packard Foundation, Wallace Research Foundation, PADI Foundation and the Arizona-Sonora Desert Museum. C. E. H. received a Masters degree bursary from the University of Exeter and the European Social Fund and would like to thank Consejo Nacional de Ciencia y TecnologĂa (Mexico) for support through a PhD scholarship. W. J. N. was supported by a Fulbright Fellowship and a Marshall Fellowship during the period field research in Baja California was conducted. B. J. G. is supported by the Darwin Initiative, European Social Fund and The Natural Environment Research Council. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Tracking leatherback turtles from the world's largest rookery: assessing threats across the South Atlantic
addresses: Centre for Ecology and Conservation, School of Biosciences, University of Exeter, Exeter, UK.notes: PMCID: PMC3119016types: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.Despite extensive work carried out on leatherback turtles (Dermochelys coriacea) in the North Atlantic and Indo-Pacific, very little is known of the at-sea distribution of this species in the South Atlantic, where the world's largest population nests in Gabon (central Africa). This paucity of data is of marked concern given the pace of industrialization in fisheries with demonstrable marine turtle bycatch in African/Latin American waters. We tracked the movements of 25 adult female leatherback turtles obtaining a range of fundamental and applied insights, including indications for methodological advancement. Individuals could be assigned to one of three dispersal strategies, moving to (i) habitats of the equatorial Atlantic, (ii) temperate habitats off South America or (iii) temperate habitats off southern Africa. While occupying regions with high surface chlorophyll concentrations, these strategies exposed turtles to some of the world's highest levels of longline fishing effort, in addition to areas with coastal gillnet fisheries. Satellite tracking highlighted that at least 11 nations should be involved in the conservation of this species in addition to those with distant fishing fleets. The majority of tracking days were, however, spent in the high seas, where effective implementation of conservation efforts is complex to achieve
Guideline-discordant androgen deprivation therapy in localized prostate cancer: patterns of use in the medicare population and cost implications
Androgen deprivation therapy (ADT) in localized prostate cancer improves overall survival and is recommended by National Comprehensive Cancer Network guidelines in certain situations. However, ADT is without benefit in other situations and can actually cause harm. This study examines recent trends in the ADT use and quantifies the cost of guideline-discordant ADT
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