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AIMS: Effective conservation of threatened or endangered species requires a robust understanding of their spatio‐temporal distribution. Although a huge amount is known about the movements of Atlantic adult sea turtles, much less is known about juvenile turtles, and much of the life history model is therefore inferred. We set out to describe the spatio‐temporal distribution of juvenile loggerheads turtles found around the Canary Islands. LOCATION: Eastern North Atlantic Ocean. METHODS: Between 1999 and 2012, we satellite‐tracked 24 healthy large juvenile loggerhead turtles (mean straight carapace length = 47.4 cm, range = 34.6–54.5 cm) captured in the waters around the Canary Islands. We describe their regional distribution, identify high‐use areas and create a model for habitat suitability using minimum convex polygons, density rasters and ensemble ecological niche modelling, integrated with physical and biological environmental data. RESULTS: Turtles used a huge oceanic area (2.5 million km²) with particularly high usage around the Canary Islands, Spain, Portugal, Morocco and Western Sahara. In spring and summer, turtles generally moved further north towards the Iberian Peninsula. Ecological niche modelling identified sea surface temperature as the most important contributory variable to the habitat models. We also recorded three juvenile turtles making westward migrations away from the eastern Atlantic Ocean, presumably back towards their original natal beaches near sexual maturity. MAIN CONCLUSIONS: The results of the present study provide insight into a significant knowledge gap on the spatio‐temporal distribution of large juvenile loggerhead turtles in the eastern Atlantic Ocean. The data highlight that turtles occupy a vast open oceanic area, which hampers the ability of static conservation approaches to afford effective protection. However, ensemble ecological niche modelling highlights key suitable habitat for juvenile loggerhead turtles, which could be used in dynamic conservation protection.

The future persistence of biodiversity is likely to be affected by global climate change. We propose a qualitative framework for assessing the resilience of coastal species to climate change, incorporating current and likely future breeding success, the availability of temporal and spatial climate refugia, the effect of future sea-level rise, behavioural plasticity and the level of other specific threats.We test this framework using one of theworld's largest nesting rookeries of loggerhead sea turtles (Caretta caretta) in the island of Boa Vista (Republic of Cape Verde, West Africa). We measured air, sand and nest temperatures across more than 50 km of nesting habitat and four years to model the likely sex ratios produced and predicted what future sex ratios might be under one conservative future climate change scenario (RCP 2.6). We assessed the relative threat of sea-level rise, and other threats including beachfront construction, pollution and human harvest as well as to estimate the level of foraging behaviour plasticity observed for this population. Estimated sex ratio over the study period was 79.15% female and while an increase of 2 °C air temperature would lead to 99.86% female production, incubation temperature is unlikely to be lethal even in the hottest part of the year. Only half the total suitable length of coastline is currently used for nesting and there is a size-linked dichotomy in foraging strategies of loggerhead turtles of both sexes. Under our qualitative framework,we make the surprising observation that this population of conservation concern should have remarkable resilience to climate change due to some unique features of their habitat use and preferences. This may be compromised by high levels of human harvest and planned and on-going coastal development. The framework may be of utility in assessing the threat of climate change to other climate-sensitive, coastal and mobile species such as migratory seabirds, coastal fish and butterflies., This work was carried out with funding from the Ministry of the Environment of the Regional Government of Andalusia, the Regional Government of the Canary Islands and the Fuerteventura Inter-Island Council (Cabildo de Fuerteventura). LAH was supported by a BBSRC post-doctoral award at Bangor University during the study.

Species invasions are a widely-recognized threat to regional and global biodiversity. Lionfish (Pterois spp.), are an invasive marine fish that have been shown to reduce the recruitment and biomass of native reef fish throughout the Caribbean. Recently, it has become clear that lionfish are able to colonise a wide range of ecosystems (mesophotic reefs to brackish estuaries to mangroves) and tolerate a wider range of salinities than previously thought. Estuarine ecosystems often experience hyposaline conditions and act as critical foraging habitats for many ecologically and economically important species. Using a habitat competition experiment at two salinity treatments (10 practical salinity units (psu) and 37 psu control) we investigated the potential effects of lionfish on native Schoolmaster snapper (Lutjanus apodus; a tropical fish species found in high abundance in estuarine ecosystems). Schoolmaster snapper showed a 62% and 47% reduction in cover use when in the presence of lionfish in the 10 psu and 37 psu treatments, respectively. Further, five of the seven behaviours investigated during the interaction period, where both lionfish and snapper had access to the shelter, showed a significant reduction at low salinity, suggesting physiological or behavioural impairment of lionfish at low salinity. Because estuarine habitats are disproportionately important habitats for juvenile fishes, even physiologically or behaviourally compromised lionfish are likely to have some impact.

International audience; The distributions of migratory species in the ocean span local, national and international jurisdictions. Across these ecologically interconnected regions, migratory marine species interact with anthropogenic stressors throughout their lives. Migratory connectivity, the geographical linking of individuals and populations throughout their migratory cycles, influences how spatial and temporal dynamics of stressors affect migratory animals and scale up to influence population abundance, distribution and species persistence. Population declines of many migratory marine species have led to calls for connectivity knowledge, especially insights from animal tracking studies, to be more systematically and synthetically incorporated into decision-making. Inclusion of migratory connectivity in the design of conservation and management measures is critical to ensure they are appropriate for the level of risk associated with various degrees of connectivity. Three mechanisms exist to incorporate migratory connectivity into international marine policy which guides conservation implementation: site-selection criteria, network design criteria and policy recommendations. Here, we review the concept of migratory connectivity and its use in international policy, and describe the Migratory Connectivity in the Ocean system, a migratory connectivity evidence-base for the ocean. We propose that without such collaboration focused on migratory connectivity, efforts to effectively conserve these critical species across jurisdictions will have limited effect.

Aims - Paragliding is a form of free flight with extreme altitude paragliding an emerging discipline. We aimed to describe the physiological demands and the impact of environmental stressors of paragliding at moderate and extreme altitudes.We recorded oxygen consumption (VO2), heart rate (HR), respiratory frequency (ƒR), tidal volume (VT), oxygen saturation, accelerometry (G) and altitude in 9.3 hours of flight at moderate altitudes (to 3,073 m, n=4), 19.3 hours at extreme altitude (to 7,458 m, n=2) and during high-G manoeuvers (n=2). We also analysed heart rate data from 17 pilots (138 hours).Results - Overall energy expenditure at moderate altitude was low (1.7 (0.6) metabolic equivalents) but physiological parameters were notably higher during take-off (p < 0.05). Pilots transiently reached ~7 G during manoeuvres. Mean HR at extreme altitude (112 (14) bpm) were elevated compared to moderate altitude (98 (15) bpm, p = 0.048). While VT were similar (p = 0.958), elevation in ƒR at extreme compared to moderate altitude approached significance (p = 0.058).Conclusions - Physical exertion in paragliding appears low, so any subjective fatigue felt by pilots is likely to be cognitive or environmental. Future research should focus on reducing mental workload, enhancing cognitive function and improving environmental protection.

Understanding spatial and temporal habitat-use patterns to protect both foraging and breeding grounds of species of concern is crucial for successful conservation. Saona Island in Del Este National Park (DENP), south-eastern Dominican Republic (DR), hosts the only major hawksbill (Eretmochelys imbricata) nesting area in the DR (100 nests yr �1 , SD = 8.4, range = 93�111), with the population having been critically reduced through hunting. We satellite tracked 9 female hawksbill turtles, and present analyses of their core-use areas with respect to Marine Protected Areas (MPAs) in both their internesting and foraging areas. Kernel utilization distribu- tions indicated that during the internesting period all turtles remained close to their nesting beaches in small home ranges in the territorial waters of the DR, mostly over the continental shelf (

Oceanographic fronts are physical interfaces between water masses that differ in properties such as temperature, salinity, turbidity and chlorophyll a enrichment. Bio-physical coupling along fronts can lead to the development of pelagic biodiversity hotspots. A diverse range of marine vertebrates have been shown to associate with fronts, using them as foraging and migration habitats. Elucidation of the ecological significance of fronts generates a better understanding of marine ecosystem functioning, conferring opportunities to improve management of anthropogenic activities in the oceans. This study presents novel insights into the oceanographic drivers of habitat use in a population of marine turtles characterised by an oceanic-neritic foraging dichotomy. Using satellite tracking data from adult female loggerhead turtles Caretta caretta nesting at Cape Verde (n = 12), we tested the hypothesis that oceanic-foraging loggerheads associate with mesocale (10s to 100s of km) thermal fronts. We used high-resolution (1 km) composite front mapping to characterise frontal activity in the Canary Current Large Marine Ecosystem over 2 temporal scales: (1) seasonal front frequency and (2) 7 d front metrics. Our use-availability analysis indicated that oceanic loggerheads show a preference for the highly productive upwelling region between Cape Verde and mainland Africa, an area of intense frontal activity. Within the upwelling region, turtles appear to forage epipelagically around mesoscale thermal fronts, exploiting profitable foraging opportunities resulting from physical aggregation of prey. © Inter-Research 2015.

The integration of satellite telemetry, remotely sensed environmental data, and habitat/environmental modelling has provided for a growing understanding of spatial and temporal ecology of species of conservation concern. The Republic of Cape Verde comprises the only substantial rookery for the loggerhead turtle Caretta caretta in the eastern Atlantic. A size related dichotomy in adult foraging patterns has previously been revealed for adult sea turtles from this population with a proportion of adults foraging neritically, whilst the majority forage oceanically. Here we describe observed habitat use and employ ecological niche modelling to identify suitable foraging habitats for animals utilising these two distinct behavioural strategies. We also investigate how these predicted habitat niches may alter under the influence of climate change induced oceanic temperature rises. We further contextualise our niche models with fisheries catch data and knowledge of fisheries ‘hotspots’ to infer threat from fisheries interaction to this population, for animals employing both strategies. Our analysis revealed repeated use of coincident oceanic habitat, over multiple seasons, by all smaller loggerhead turtles, whilst larger neritic foraging turtles occupied continental shelf waters. Modelled habitat niches were spatially distinct, and under the influence of predicted sea surface temperature rises, there was further spatial divergence of suitable habitats. Analysis of fisheries catch data highlighted that the observed and modelled habitats for oceanic and neritic loggerhead turtles could extensively interact with intensive fisheries activity within oceanic and continental shelf waters of northwest Africa. We suggest that the development and enforcement of sustainable management strategies, specifically multi-national fisheries policy, may begin to address some of these issues; however, these must be flexible and adaptive to accommodate potential range shift for this species.

Climate change models predict sea level rise and increased intensity of storms and hurricanes in tropical sea turtle nesting areas. These factors could significantly increase beach inundation and erosion, thus affecting water content of sea turtle nesting beaches. Here, we conducted a field and laboratory study of how sand water content is related to embryonic development and hatching success of leatherback turtle nests. Moreover, we have experimentally incubated eggs of this species in beach sand under standardized conditions, but at different realistic levels of sand water content, varying from 1% to 12%. On the beaches, females nested from the intertidal zone to the lower part of the sand vegetation dunes, where nests were exposed to a wide range of sand water contents that ranged from 0.8% to 22%. However, both field and experimental studies revealed a strong negative correlation between sand water content and emergence success (field study: r = − 0.73, P

Global climate change is expected to have major impacts on biodiversity. Sea turtles have temperature-dependent sex determination, and many populations produce highly female-biased offspring sex ratios, a skew likely to increase further with global warming. We estimated the primary sex ratio at one of the world’s largest green turtle Chelonia mydas rookeries in Guinea-Bissau, West Africa, and explored its resilience to climate change. In 2013 and 2014, we deployed data loggers recording nest (n = 101) and sand (n = 30) temperatures, and identified hatchling sex by histological examination of gonads. A logistic curve was fitted to the data to allow predictions of sex ratio across habitats and through the nesting season. The population-specific pivotal temperature was 29.4°C, with both sexes produced within incubation temperatures from 27.6 to 31.4°C: the transitional range of temperatures (TRT). Primary sex ratio changed from male- to female-biased across relatively small temporal and spatial scales. Overall it was marginally female-biased, but we estimated an exceptionally high male hatchling production of 47.7% (95% CI: 36.7-58.3%) and 44.5% (95% CI: 33.8-55.4%) in 2013 and 2014, respectively. Both the temporal and spatial variation in incubation conditions and the wide range of the TRT suggest resilience and potential for adaptation to climate change if the present nesting habitat remains unchanged. These findings underline the importance of assessing site-specific parameters to understand populations’ responses to climate change, particularly with regard to identifying rookeries with high male hatchling production that may be key for the future conservation of sea turtles under projected global warming scenarios.

Exercise at high altitude is extremely challenging, largely due to hypobaric hypoxia (low oxygen levels brought about by low air pressure). In humans, the maximal rate of oxygen consumption decreases with increasing altitude, supporting progressively poorer performance. Bar-headed geese (Anser indicus) are renowned high altitude migrants and, although they appear to minimize altitude during migration where possible, they must fly over the Tibetan Plateau (mean altitude 4800 m) for much of their annual migration. This requires considerable cardiovascular effort, but no study has assessed the extent to which bar-headed geese may train prior to migration for long distances, or for high altitudes. Using implanted loggers that recorded heart rate, acceleration, pressure, and temperature, we found no evidence of training for migration in bar-headed geese. Geese showed no significant change in summed activity per day or maximal activity per day. There was also no significant change in maximum heart rate per day or minimum resting heart rate, which may be evidence of an increase in cardiac stroke volume if all other variables were to remain the same. We discuss the strategies used by bar-headed geese in the context of training undertaken by human mountaineers when preparing for high altitude, noting the differences between their respective cardiovascular physiology. published

Summary 1. Identifying priority areas for marine vertebrate conservation is complex because species of conservation concern are highly mobile, inhabit dynamic habitats and are difficult to monitor. 2. Many marine vertebrates are known to associate with oceanographic fronts – physical interfaces at the transition between water masses – for foraging and migration, making them important candidate sites for conservation. Here, we review associations between marine vertebrates and fronts and how they vary with scale, regional oceanography and foraging ecology. 3. Accessibility, spatiotemporal predictability and relative productivity of front-associated foraging habitats are key aspects of their ecological importance. Predictable mesoscale (10s– 100s km) regions of persistent frontal activity (‘frontal zones’) are particularly significant. 4. Frontal zones are hotspots of overlap between critical habitat and spatially explicit anthropogenic threats, such as the concentration of fisheries activity. As such, they represent tractable conservation units, in which to target measures for threat mitigation. 5. Front mapping via Earth observation (EO) remote sensing facilitates identification and monitoring of these hotspots of vulnerability. Seasonal or climatological products can locate biophysical hotspots, while near-real-time front mapping augments the suite of tools supporting spatially dynamic ocean management. 6. Synthesis and applications. Frontal zones are ecologically important for mobile marine vertebrates. We surmise that relative accessibility, predictability and productivity are key biophysical characteristics of ecologically significant frontal zones in contrasting oceanographic regions. Persistent frontal zones are potential priority conservation areas for multiple marine vertebrate taxa and are easily identifiable through front mapping via EO remote sensing. These insights are useful for marine spatial planning and marine biodiversity conservation, both within Exclusive Economic Zones and in the open oceans.

Management of species of conservation concern requires knowledge of demographic parameters, such as rates of recruitment, survival, and growth. In the Caribbean, hawksbill turtles (Eretmochelys imbricata) have been historically exploited in huge numbers to satisfy trade in their shells and meat. In the present study, we estimated growth rate of juvenile hawksbill turtles around Anegada, British Virgin Islands, using capture-mark-recapture of 59 turtles over periods of up to 649 days. Turtles were recaptured up to six times, having moved up to 5.9 km from the release location. Across all sizes, turtles grew at an average rate of 9.3 cm year(-1) (range 2.3-20.3 cm year(-1)), and gained mass at an average of 3.9 kg year(-1) (range 850 g-16.1 kg year(-1)). Carapace length was a significant predictor of growth rate and mass gain, but there was no relationship between either variable and sea surface temperature. These are among the fastest rates of growth reported for this species, with seven turtles growing at a rate that would increase their body size by more than half per year (51-69% increase in body length). This study also demonstrates the importance of shallow water reef systems for the developmental habitat for juvenile hawksbill turtles. Although growth rates for posthatching turtles in the pelagic, and turtles larger than 61 cm, are not known for this population, the implications of this study are that Caribbean hawksbill turtles in some areas may reach body sizes suggesting sexual maturity in less time than previously considered.

The basking shark (Cetorhinus maximus) is an endangered species in the north-east Atlantic, having been historically over exploited. Whilst near-shore aggregation hotspots in the UK have been identified, robust knowledge on species distribution and abundance outside these areas remains limited. Research techniques, such as habitat modelling, could however be used to gain a greater knowledge of the species distribution to inform management plans to aid population recovery. For large mobile species gathering wide-scale distribution data can be financially and logistically challenging. In lieu of conducting an expensive UK-wide strategic survey for basking sharks, we use data from two regional-scale surveys, which were conducted in southwest England and western Scotland, in an Ensemble Ecological Niche Model (EENM) to produce a spatially-explicit map of habitat suitability. When compared against a ~20-year database of public sightings of basking sharks across UK coastal seas (to 6 nautical miles offshore), patterns of habitat suitability yielded a statistically significant agreement with areas known to support basking shark sightings. EENMs could be used to advise Marine Protected Area (MPA) selection, as well as to inform environmental impact assessments for offshore developments. The application of EENM outputs could be wide-reaching and benefit not only basking sharks but other large mobile marine species in the north-east Atlantic.

From 1998 to 2008, 68 adult female loggerhead sea turtles (Caretta caretta) were instrumented with platform transmitter terminals at nesting beaches in Georgia, North Carolina (NC) and South Carolina (SC) on the East Coast of the United States of America (30°48′N, 81°28′W to 33°51′N, 77°59′W). The majority of post-nesting loggerheads (N = 42, 62 %) migrated to foraging habitats in the Mid-Atlantic Bight during May–October, with a subsequent migration occurring during November–March to foraging habitats south of Cape Hatteras, NC. Nine (13 %) loggerheads initially foraged in the near-shore, coastal areas of the South Atlantic Bight, but moved to offshore habitats—closer to the Gulf Stream—during November–March, while fourteen (21 %) loggerheads remained in foraging areas along the mid-continental shelf off of the eastern coast of Florida and/or continued southward to Florida Bay and the Bahamas. The present study delineates important, post-nesting foraging habitats and migration corridors where loggerheads may interact with commercial fisheries—providing managers opportunities to develop and implement optimally effective conservation actions for the recovery of this threatened species.

In recent years, information about the movements and timing of migration by male sea turtles has begun to be unraveled. Here, we present the first satellite tracking of male loggerhead sea turtles ( Caretta caretta ) in the eastern Atlantic. Satellite linked transmitters were attached to five adult males, captured in the near shore waters off Boavista, Republic of Cape Verde. This archipelago hosts the single most important breeding site of loggerhead turtles in the eastern Atlantic. Animals were tracked for periods ranging between 48 and 537 days, including a probable annual remigration to the vicinity of the nesting ground for one turtle. Males showed a variety of movement patterns both during and after the breeding season. Of three males that transmitted for 85, 329 and 537 days, two (the smallest) migrated east and remained in oceanic waters for the tracking period and another (larger turtle) migrated 810 km northeast, to neritic waters off the coast of Mauritania, Western Africa. Results suggest males may show the same size-linked dichotomy in migratory strategies, as has been shown for females from this population.

Evolutionary theory predicts that male and female offspring should be produced at a 1:1 ratio, but this may rarely be the case for species in which sex is determined during incubation by temperature, such as marine turtles. Estimates of primary sex ratio suggest that marine turtle sex ratios are highly skewed, with up to 9 females per male. We captured juvenile hawksbill turtles Eretmochelys imbricata in waters around Anegada, British Virgin Islands, a regionally important foraging aggregation, and analysed concentrations of plasma testosterone and oestra- diol-17β from 62 turtles to estimate sex ratio. There were 2.4 to 7.7 times more females than males. Testosterone concentrations correlated with sampling date and sea surface temperature (SST), with higher con centrations in the late summer when SST was highest, suggesting that assigning sex through threshold values of sex hormones must be carried out cautiously. The sex ratio in the juvenile foraging aggregation around Anegada is more male biased than at other locations, sug- gesting that turtles at Anegada have resilience against feminising effects of climate change. Future work should (1) integrate the relative contributions of different genetic stocks to foraging aggregations and (2) investigate the annual and seasonal cycles of sex hormones, and differences among individuals and life history stages.

Somatic growth dynamics are an integrated response to environmental conditions. Hawksbill sea turtles (Eretmochelys imbricata) are long‐lived, major consumers in coral reef habitats that move over broad geographic areas (hundreds to thousands of kilometers). We evaluated spatio‐temporal effects on hawksbill growth dynamics over a 33‐yr period and 24 study sites throughout the West Atlantic and explored relationships between growth dynamics and climate indices. We compiled the largest ever data set on somatic growth rates for hawksbills – 3541 growth increments from 1980 to 2013. Using generalized additive mixed model analyses, we evaluated 10 covariates, including spatial and temporal variation, that could affect growth rates. Growth rates throughout the region responded similarly over space and time. The lack of a spatial effect or spatio‐temporal interaction and the very strong temporal effect reveal that growth rates in West Atlantic hawksbills are likely driven by region‐wide forces. Between 1997 and 2013, mean growth rates declined significantly and steadily by 18%. Regional climate indices have significant relationships with annual growth rates with 0‐ or 1‐yr lags: positive with the Multivariate El Niño Southern Oscillation Index (correlation = 0.99) and negative with Caribbean sea surface temperature (correlation = −0.85). Declines in growth rates between 1997 and 2013 throughout the West Atlantic most likely resulted from warming waters through indirect negative effects on foraging resources of hawksbills. These climatic influences are complex. With increasing temperatures, trajectories of decline of coral cover and availability in reef habitats of major prey species of hawksbills are not parallel. Knowledge of how choice of foraging habitats, prey selection, and prey abundance are affected by warming water temperatures is needed to understand how climate change will affect productivity of consumers that live in association with coral reefs.

The advent of telemetry has improved knowledge of the spatio-temporal distribution of marine species of conservation concern. Among the sea turtles, the movements of the hawksbill turtle Eretmochelys imbricata are among the least well described. We tracked 10 adult female hawksbill turtles by satellite after nesting in the Dominican Republic (DR) and describe a dichotomy in patterns of movement: some (n = 2) turtles remained in the DR, while others migrated to waters off Honduras and Nicaragua (n = 5) and the Bahamas (n = 1). Transmitters on 2 turtles failed during migration, before they reached their final foraging grounds. We present results from long tracking durations for 3 turtles, including 3 entire remigration intervals, high- lighting foraging ground and nest-site fidelity. Threats to hawksbill turtles are not well docu- mented for Nicaragua or neighbouring Honduras and represent a major information gap. We sug- gest that directing conservation efforts to regionally important foraging areas, such as those in Nicaragua, and strengthening national conservation in each nation with significant hawksbill nesting offers a clear way forward for the conservation of hawksbill turtles in the region.

Conserving and managing populations of marine vertebrates can be complex when they occupy the waters of multiple nations, crossing heterogeneous legal and management landscapes. Hawksbill turtles ( Eretmochelys imbricata ) are subject to varying levels of use in Caribbean countries and their conservation and management is complicated by the extent to which they are a ‘shared’ resource. In 1997 and 2000, Cuba attempted to ‘downlist’ hawksbills from Cuban waters to CITES Appendix II to allow limited international trade. The research on movement and dispersal of hawksbills reported here was undertaken to better inform discussion about the impacts of their harvest. Flipper tagging and satellite tracking demonstrate that the majority of study turtles remained in Cuban territorial waters. Of 1170 hawksbills tagged (525 adults and 606 juveniles), 12% ( n = 143) were recaptured. All recaptured adults ( n = 16 males, 38 nesting females and 30 adult females in-water) were in Cuban waters. Of the 59 juveniles recaptured, only four recaptures were outside Cuban waters (Nicaragua = 2, Colombia = 1, USA = 1). Fourteen hawksbills tagged in the waters of other nations were recaptured in Cuban waters. We also satellite tracked 21 turtles (one adult male, ten nesting females and ten non-nesting adult females), of which five tags failed, 11 stayed in Cuban waters for the duration of transmissions (1–809 days) and five foraged in the waters of other nations (Mexico n = 1 an adult female; Honduras n = 2, both post-nesting turtles; Colombia n = 1 an adult female; and the eastern Lesser Antilles n = 1, an adult male), with differences for nesting and non-nesting turtles. Our results, demonstrating extended site fidelity within Cuban waters, suggest that strengthening national management within national jurisdictions that host hawksbill turtles is fundamental to improving regional conservation as a whole.

Aim Although satellite tracking has yielded much information regarding the migrations and habitat use of threatened marine species, relatively little has been published about the environmental niche for loggerhead sea turtles Caretta caretta in north-west Atlantic waters. Location North Carolina, South Carolina and Georgia, USA. Methods We tracked 68 adult female turtles between 1998 and 2008, one of the largest sample sizes to date, for 372.2 ± 210.4 days (mean ± SD). Results We identified two strategies: (1) ‘seasonal’ migrations between summer and winter coastal areas (n = 47), although some turtles made oceanic excursions (n = 4) and (2) occupation of more southerly ‘year-round’ ranges (n = 18). Seasonal turtles occupied summer home ranges of 645.1 km2 (median, n = 42; using α-hulls) predominantly north of 35 ° latitude and winter home ranges of 339.0 km2 (n = 24) in a relatively small area on the narrow shelf off North Carolina. We tracked some of these turtles through successive summer (n = 8) and winter (n = 3) seasons, showing inter-annual home range repeatability to within 14.5 km of summer areas and 10.3 km of winter areas. For year-round turtles, home ranges were 1889.9 km2. Turtles should be tracked for at least 80 days to reliably estimate the home range size in seasonal habitats. The equivalent minimum duration for ‘year-round’ turtles is more complex to derive. We define an environmental envelope of the distribution of North American loggerhead turtles: warm waters (between 18.2 and 29.2 °C) on the coastal shelf (in depths of 3.0–89.0 m). Main conclusions Our findings show that adult female loggerhead turtles show predictable, repeatable home range behaviour and do not generally leave waters of the USA, nor the continental shelf (

Virulent outbreaks of highly pathogenic avian influenza (HPAI) since 2005 have raised the question about the roles of migratory and wild birds in the transmission of HPAI. Despite increased monitoring, the role of wild waterfowl as the primary source of the highly pathogenic H5N1 has not been clearly established. The impact of outbreaks of HPAI among species of wild birds which are already endangered can nevertheless have devastating consequences for the local and non-local ecology where migratory species are established. Understanding the entangled dynamics of migration and the disease dynamics will be key to prevention and control measures for humans, migratory birds and poultry. Here, we present a spatial dynamic model of seasonal migration derived from first principles and linking the local dynamics during migratory stopovers to the larger scale migratory routes. We discuss the effect of repeated epizootic at specific migratory stopovers for bar-headed geese ( Anser indicus ). We find that repeated deadly outbreaks of H5N1 on stopovers during the autumn migration of bar-headed geese could lead to a larger reduction in the size of the equilibrium bird population compared with that obtained after repeated outbreaks during the spring migration. However, the opposite is true during the first few years of transition to such an equilibrium. The age-maturation process of juvenile birds which are more susceptible to H5N1 reinforces this result.

SUMMARY Marine turtles utilise terrestrial and marine habitats and several aspects of their life history are tied to environmental features that are altering due to rapid climate change. We overview the likely impacts of climate change on the biology of these species, which are likely centred upon the thermal ecology of this taxonomic group. Then, focusing in detail on three decades of research on the loggerhead turtle (Caretta caretta L.), we describe how much progress has been made to date and how future experimental and ecological focus should be directed. Key questions include: what are the current hatchling sex ratios from which to measure future climate-induced changes? What are wild adult sex ratios and how many males are necessary to maintain a fertile and productive population? How will climate change affect turtles in terms of their distribution?

Understanding the spatial movements of threatened marine species, such as sea turtles, is essential as a means of informing appropriate conservation management. Although novel tech- niques for tracking spatial movements are becoming more widely available (such as satellite track- ing), simple techniques such as mark-release-recapture remain effective. A flipper tagging and recovery program in Cuba tagged 210 loggerhead turtles over 14 yr and recovered 7% of the tags between 2 d and 3 yr later (mean = 296 d). All but one turtle was recaptured in Cuban waters, and data showed limited movement of turtles between northern and southern coasts. A further 50 turtles were recovered that had been tagged in foreign projects, the majority of which were from the USA (but also Mexico, The Bahamas, Canary Islands and Spain). A range of life stages of loggerhead tur- tles are found in Cuban waters year-round, and given that Cuba has the second largest reef in the Caribbean, it likely provides foraging habitat for significant numbers of loggerhead turtles from at least 6 different countries.

The use of satellite tracking for the fundamental and applied study of marine turtles began in the 1980s but has undergone rapid growth in recent years. To provide a background against which to judge the past success and future directions of these research efforts we carried out a com- prehensive review of over 130 scientific papers on the use of this technique in this taxon. We show how satellite tracking has changed over time as well as outlining biases in spatial, species and life- stage coverage. Descriptions of migration routes and other habitats have offered novel insights into the basic life history patterns of some species, highlighted focal areas for conservation and reinforced the multi-national nature of the stakeholders of many populations. In foraging areas, knowledge is growing as to how animals move within dynamic seascapes, thus facilitating our understanding of 3-dimensional habitat use and seasonal patterns of behaviour. More experimental approaches have elucidated navigational capabilities and post-release survival following fisheries interaction and long-term captivity. In addition, through the Internet and other media, satellite tracking appears to have been effective in engaging public attention in many countries. Finally, we discuss why the use of the technique has increased so markedly over time and point out key areas of concern that we feel should be addressed by the community of researchers and donors who focus on sea turtles.

Although the Atlantic waters of North America support hundreds of thousands of loggerhead sea turtles (Caretta caretta), remarkably little is known regarding their migratory ecology and habitat use. We integrate satellite tracking with remotely sensed oceanographic data to uncover two different migratory strategies used by loggerhead turtles at the northern part of their range. Most turtles travelled from the nesting beach to forage at higher latitudes in summer, before migrating south to wintering grounds in the autumn. Others moved south after nesting to forage for up to 514 days and did not make an autumn migration. Both groups utilized warm waters at the very edge of the Gulf Stream during winter: for southerly turtles obviating seasonal migration, and for northerly turtles minimizing the distance, time and energy required to reach northern areas for subsequent foraging seasons, avoiding lethally cold winter temperatures in inshore waters at the same latitude, and reducing energy costs that would be incurred within the fast-flowing Gulf Stream. Females made long resting dives of up to 7 h 24 min, effectively hibernating during the colder months. Offshore federal waters of the USA constitute a more important habitat for both foraging and wintering turtles than previously appreciated. These areas are potential hotspots for interaction with fisheries and proposed US military training activities and should receive special monitoring efforts to fully assess the extent of overlap.

Recent increases in global temperatures have affected the phenology and survival of many species of plants and animals. We investigated a case study of the effects of potential climate change on a thermally sensitive species, the loggerhead sea turtle, at a breeding location at the northerly extent of the range of regular nesting in the United States. In addition to the physical limits imposed by temperature on this ectothermic species, sea turtle primary sex ratio is determined by the temperature experienced by eggs during the middle third of incubation. We recorded sand temperatures and used historical air temperatures (ATs) at Bald Head Island, NC, to examine past and predict future sex ratios under scenarios of warming. There were no significant temporal trends in primary sex ratio evident in recent years and estimated mean annual sex ratio was 58% female. Similarly, there were no temporal trends in phenology but earlier nesting and longer nesting seasons were correlated with warmer sea surface temperature. We modelled the effects of incremental increases in mean AT of up to 7.5°C, the maximum predicted increase under modelled scenarios, which would lead to 100% female hatchling production and lethally high incubation temperatures, causing reduction in hatchling production. Populations of turtles in more southern parts of the United States are currently highly female biased and are likely to become ultra-biased with as little as 1°C of warming and experience extreme levels of mortality if warming exceeds 3°C. The lack of a demonstrable increase in AT in North Carolina in recent decades coupled with primary sex ratios that are not highly biased means that the male offspring from North Carolina could play an increasingly important role in the future viability of the loggerhead turtle in the Western Atlantic.

The ''landscape of fear'' model has been proposed as a unifying concept in ecology, describing, in part, how animals behave and move about in their environment. The basic model predicts that as an animal's landscape changes from low to high risk of predation, prey species will alter their behavior to risk avoidance. However, studies investigating and evaluating the landscape of fear model across large spatial scales (tens to hundreds of thousands of square kilometers) in dynamic, open, aquatic systems involving apex predators and highly mobile prey are lacking. To address this knowledge gap, we investigated predator- prey relationships between tiger sharks (Galeocerdo cuvier) and loggerhead turtles (Caretta caretta) in the North Atlantic Ocean. This included the use of satellite tracking to examine shark and turtle distributions as well as their surfacing behaviors under varying levels of home range overlap. Our findings revealed patterns that deviated from our a priori predictions based on the landscape of fear model. Specifically, turtles did not alter their surfacing behaviors to risk avoidance when overlap in shark-turtle core home range was high. However, in areas of high overlap with turtles, sharks exhibited modified surfacing behaviors that may enhance predation opportunity. We suggest that turtles may be an important factor in determining shark distribution, whereas for turtles, other life history trade-offs may play a larger role in defining their habitat use. We propose that these findings are a result of both biotic and physically driven factors that independently or synergistically affect predator-prey interac- tions in this system. These results have implications for evolutionary biology, community ecology, and wildlife conservation. Further, given the difficulty in studying highly migratory marine species, our approach and conclusions may be applied to the study of other predator- prey systems.

Population connectivity is an important consideration in studies of disease transmission and biological conservation, especially with regard to migratory species. Determining how and when different subpopulations intermingle during different phases of the annual cycle can help identify important geographical regions or features as targets for conservation efforts and can help inform our understanding of continental-scale disease transmission. In this study, stable isotopes of hydrogen and carbon in contour feathers were used to assess the degree of molt-site fidelity among Bar-headed Geese (Anser indicus) captured in north-central Mongolia. Samples were collected from actively molting Bar-headed Geese (n = 61), and some individual samples included both a newly grown feather (still in sheath) and an old, worn feather from the bird's previous molt (n = 21). Although there was no difference in mean hydrogen isotope ratios for the old and new feathers, the isotopic variance in old feathers was approximately three times higher than that of the new feathers, which suggests that these birds use different and geographically distant molting locations from year to year. To further test this conclusion, online data and modeling tools from the isoMAP website were used to generate probability landscapes for the origin of each feather. Likely molting locations were much more widespread for old feathers than for new feathers, which supports the prospect of low molt-site fidelity. This finding indicates that population connectivity would be greater than expected based on data from a single annual cycle, and that disease spread can be rapid even in areas like Mongolia where Bar-headed Geese generally breed in small isolated groups.

Bar-headed geese cross the Himalayas on one of the most iconic high-altitude migrations in the world. Heart rates and metabolic costs of flight increase with elevation and can be near maximal during steep climbs. Their ability to sustain the high oxygen demands of flight in air that is exceedingly oxygen-thin depends on the unique cardiorespiratory physiology of birds in general along with several evolved specializations across the O2transport cascade.

Geese need to hug the land to fly high Animal migrations provide numerous examples of astonishing feats. Impressive even among these is the migration of bar-headed geese across the Himalayan Mountains, which reach heights of thousands of meters. Bishop et al. remotely monitored birds' heart rates, movement, and body temperature during migration. The geese “hug” the landforms, taking advantage of drafting and wind patterns. This unexpected strategy conserves energy, even though it means the geese repeatedly lose, and must then regain, altitude. Science , this issue p. 250

Summary Marine turtles undergo dramatic ontogenic changes in body size and behavior, with the loggerhead sea turtle, Caretta caretta , typically switching from an initial oceanic juvenile stage to one in the neritic, where maturation is reached and breeding migrations are subsequently undertaken every 2–3 years [1–3]. Using satellite tracking, we investigated the migratory movements of adult females from one of the world's largest nesting aggregations at Cape Verde, West Africa. In direct contrast with the accepted life-history model for this species [4], results reveal two distinct adult foraging strategies that appear to be linked to body size. The larger turtles (n = 3) foraged in coastal waters, whereas smaller individuals (n = 7) foraged oceanically. The conservation implications of these findings are profound, with the population compartmentalized into habitats that may be differentially impacted by fishery threats in what is a global fishing hotspot [5]. Although the protection of discrete areas containing coastal individuals may be attainable, the more numerous pelagic individuals are widely dispersed with individuals roaming over more than half a million square kilometers. Therefore, mitigation of fisheries by-catch for sea turtles in the east Atlantic will likely require complex and regionally tailored actions to account for this dichotomous behavior.

A 24-year set of data from monitoring of a nesting beach at Bald Head Island, North Carolina, USA, was analysed in parallel with limited data from nearby rookeries to investigate trends in loggerhead turtle Caretta caretta nesting numbers. There was no statistical evidence of an increasing or decreasing trend in numbers of clutches laid per year, although a significant decrease in the number of turtles nesting and number of clutches laid per year was found from 1991. Remigrating turtles were larger and had larger annual clutch frequencies than neophyte turtles. Annual levels of nesting at beaches within the Cape Fear area were significantly correlated. The stable trend in number of clutches laid across more than two decades is discussed in relation to other factors affecting marine turtles in North American waters.

While bar-headed geese are renowned for migration at high altitude over the Himalayas, previous work on captive birds suggested that these geese are unable to maintain rates of oxygen consumption while running in severely hypoxic conditions. To investigate this paradox, we re-examined the running performance and heart rates of bar-headed geese and barnacle geese (a low altitude species) during exercise in hypoxia. Bar-headed geese (n = 7) were able to run at maximum speeds (determined in normoxia) for 15 minutes in severe hypoxia (7% O2; simulating the hypoxia at 8500 m) with mean heart rates of 466±8 beats min-1. Barnacle geese (n = 10), on the other hand, were unable to complete similar trials in severe hypoxia and their mean heart rate (316 beats.min-1) was significantly lower than bar-headed geese. In bar-headed geese, partial pressures of oxygen and carbon dioxide in both arterial and mixed venous blood were significantly lower during hypoxia than normoxia, both at rest and while running. However, measurements of blood lactate in bar-headed geese suggested that anaerobic metabolism was not a major energy source during running in hypoxia. We combined these data with values taken from the literature to estimate (i) oxygen supply, using the Fick equation and (ii) oxygen demand using aerodynamic theory for bar-headed geese flying aerobically, and under their own power, at altitude. This analysis predicts that the maximum altitude at which geese can transport enough oxygen to fly without environmental assistance ranges from 6,800 m to 8,900 m altitude, depending on the parameters used in the model but that such flights should be rare.

The bar-headed goose (Anser indicus) undergoes a biannual migration over the Himalayas, sustaining aerobic flight above 6,000 meters. The goal of our study was to collect cardiorespiratory and metabolic data during flight from geese flying in a wind tunnel in normoxia and two levels of hypoxia simulating altitude. In birds at rest, metabolic rate fell from 26.6 ± 1.3 mL min-1 kg-1 to 10.0 ± 0.9 mL min-1 kg-1 and 10.7 ± 4.8 mL min-1 kg-1 in normoxia, 10.5% O2 and 7% O2 respectively. It rose to 209.8 ± 5.2 mL min-1 kg-1 during flight in normoxia but decreased to 181.7 ± 5.0 mL min-1 kg-1 in 10.5% O2 and to 131.7 ± 7.1 mL min-1 kg-1 in birds during flight in 7% O2. We found no change in heart rate across oxygen levels at rest or in flight. Heart rate at rest averaged 116.3 ± 35.4. While in flight, for any given metabolic rate we found a large range of heart rates in some individuals (184.5 to 457.0) and a very small range of heart rates in other individuals (256.8 to 375.7). There was, however, a strong posi...

Nesting by three species of marine turtles persists in the Dominican Republic, despite historic threats and long-term population decline. We conducted a genetic survey of marine turtles in the Dominican Republic in order to link them with other rookeries around the Caribbean. We sequenced a 740bp fragment of the control region of the mitochondrial DNA of 92 samples from three marine turtle species [hawksbill (n = 48), green (n = 2) and leatherback (n = 42)], and incorporated published data from other nesting populations and foraging grounds. The leatherback turtle (Dermochelys coriacea) in the Dominican Republic appeared to be isolated from Awala-Yalimapo, Cayenne, Trinidad and St. Croix but connected with other Caribbean populations. Two distinct nesting populations of hawksbill turtles (Eremochelys imbricata) were detected in the Dominican Republic and exhibited interesting patterns of connectivity with other nesting sites and juvenile and adult male foraging aggregations. The green sea turtle (Chelonia mydas) has almost been extirpated from the Dominican Republic and limited inference could be made from our samples. Finally, results were compared with Lagrangian drifting buoys and published Lagrangian virtual particles that travelled through the Dominican Republic and Caribbean waters. Conservation implications of sink-source effects or genetic isolation derived from these complex inter-connections are discussed for each species and population.

Bar-headed geese are renowned for migratory flights at extremely high altitudes over the world's tallest mountains, the Himalayas, where partial pressure of oxygen is dramatically reduced while flight costs, in terms of rate of oxygen consumption, are greatly increased. Such a mismatch is paradoxical, and it is not clear why geese might fly higher than is absolutely necessary. In addition, direct empirical measurements of high-altitude flight are lacking. We test whether migrating bar-headed geese actually minimize flight altitude and make use of favourable winds to reduce flight costs. By tracking 91 geese, we show that these birds typically travel through the valleys of the Himalayas and not over the summits. We report maximum flight altitudes of 7290 m and 6540 m for southbound and northbound geese, respectively, but with 95 per cent of locations received from less than 5489 m. Geese travelled along a route that was 112 km longer than the great circle (shortest distance) route, with transit ground speeds suggesting that they rarely profited from tailwinds. Bar-headed geese from these eastern populations generally travel only as high as the terrain beneath them dictates and rarely in profitable winds. Nevertheless, their migration represents an enormous challenge in conditions where humans and other mammals are only able to operate at levels well below their sea-level maxima.

It is now well understood that climate change has the potential to dramatically affect biodiversity, with effects on spa- tio-temporal distribution patterns, trophic relationships and survivorship. In the marine turtles, sex is determined by incubation temperature, such that warming temperatures could lead to a higher production of female hatchlings. By measuring nest temperature, and using a model to relate the incubation temperature to sex ratio, we estimate that Caribbean Colombian leatherback sea turtles currently produce approximately 92% female hatchlings. We modelled the relationship between incubation, sand and air temperature, and under all future climate change scenarios (0.4–6.0 °C warming over the next 100 years), complete feminization could occur, as soon as the next decade. How- ever, male producing refugia exist in the periphery of smaller nests (0.7 °C cooler at the bottom than at the centre), within beaches (0.3 °C cooler in the vegetation line and inter-tidal zone) and between beaches (0.4 °C higher on dark beaches), and these natural refugia could be assigned preferential conservation status. However, there exists a need to develop strategies that may ameliorate deleterious effects of climate-induced temperature changes in the future. We experimentally shaded clutches using screening material, and found that it was effective in reducing nest temper- ature, producing a higher proportion of male hatchlings, without compromising the fitness or hatching success. Arti- ficial shade in hatcheries is a very useful and simple tool in years or periods of high environmental temperatures. Nevertheless, this is only an emergency response to the severe impacts that will eventually have to be reversed if we are to guarantee the stability of the populations.

We describe the real-time movements of the last of the marine mega-vertebrate taxa to be satellite tracked – the giant manta ray (or devil fish, Manta birostris), the world's largest ray at over 6 m disc width. Almost nothing is known about manta ray movements and their environmental preferences, making them one of the least understood of the marine mega-vertebrates. Red listed by the International Union for the Conservation of Nature as ‘Vulnerable’ to extinction, manta rays are known to be subject to direct and incidental capture and some populations are declining. Satellite-tracked manta rays associated with seasonal upwelling events and thermal fronts off the Yucatan peninsula, Mexico, and made short-range shuttling movements, foraging along and between them. The majority of locations were received from waters shallower than 50 m deep, representing thermally dynamic and productive waters. Manta rays remained in the Mexican Exclusive Economic Zone for the duration of tracking but only 12% of tracking locations were received from within Marine Protected Areas (MPAs). Our results on the spatio-temporal distribution of these enigmatic rays highlight opportunities and challenges to management efforts.

Birds arose from their dinosaur ancestors and took to the skies over 100 million years ago. Since that time, birds have become abundant at high elevation, they have acquired the ability to migrate over the world's highest mountains, and they have even found reason to soar over 11,000 m above sea

Birds that fly over mountain barriers must be capable of meeting the increased energetic cost of climbing in low-density air, even though less oxygen may be available to support their metabolism. This challenge is magnified by the reduction in maximum sustained climbing rates in large birds. Bar-headed geese ( Anser indicus ) make one of the highest and most iconic transmountain migrations in the world. We show that those populations of geese that winter at sea level in India are capable of passing over the Himalayas in 1 d, typically climbing between 4,000 and 6,000 m in 7–8 h. Surprisingly, these birds do not rely on the assistance of upslope tailwinds that usually occur during the day and can support minimum climb rates of 0.8–2.2 km·h −1 , even in the relative stillness of the night. They appear to strategically avoid higher speed winds during the afternoon, thus maximizing safety and control during flight. It would seem, therefore, that bar-headed geese are capable of sustained climbing flight over the passes of the Himalaya under their own aerobic power.

The loggerhead turtle (Caretta caretta) is an endangered marine reptile for whom assessing population health requires knowledge of demographic parameters such as individual growth rate. In Cape Verde, as within several populations, adult female loggerhead sea turtles show a size-related behavioral and trophic dichotomy. While smaller females are associated with oceanic habitats, larger females tend to feed in neritic habitats, which is reflected in their physiological condition and in their offspring. The ratio of RNA/DNA provides a measure of cellular protein synthesis capacity, which varies depending on changes in environmental conditions such as temperature and food availability. The purpose of this study was to evaluate the combined use of morphometric data and biochemical indices as predictors of the physiological condition of the females of distinct sizes and hatchlings during their nesting season and how temperature may influence the physiological condition on the offspring. Here we employed biochemical indices based on nucleic acid derived indices (standardized RNA/DNA ratio-sRD, RNA concentration and DNA concentration) in skin tissue as a potential predictor of recent growth rate in nesting females and hatchling loggerhead turtles. Our major findings were that the physiological condition of all nesting females (sRD) decreased during the nesting season, but that females associated with neritic habitats had a higher physiological condition than females associated with oceanic habitats. In addition, the amount of time required for a hatchling to right itself was negatively correlated with its physiological condition (sRD) and shaded nests produced hatchlings with lower sRD. Overall, our results showed that nucleic acid concentrations and ratios of RNA to DNA are an important tool as potential biomarkers of recent growth in marine turtles. Hence, as biochemical indices of instantaneous growth are likely temperature-, size- and age-dependent, the utility and validation of these indices on marine turtles stocks deserves further study. The authors thank the Cape Verde Ministry of Environment (General Direction for the Environment), INDP (National Fisheries Institution), the Canary Islands Government (D.G. Africa and D.G. Research and Universities), ICCM (Canarian Institution for Marine Sciences), the Andalusian Government (Andalusian Environmental Office) and AEGINA PROJECT (INTERREG IIIB) for funding and hosting them during this study. The authors also thank the European Regional Development Fund (ERDF) through the COMPETE - Operational Competitiveness Programme, and national funds through FCT - PEst-C/MAR/LA0015/2011 for supporting the biochemical analysis.

Differential foraging area use can affect population demographics of highly migratory fauna because of differential environmental changes and anthropogenic threats among those areas. Thus, identification of foraging areas is vital for the development of effective management strategies for endangered migratory species. In this study, we assigned 375 loggerhead turtles (Caretta caretta) nesting at six locations along the east coast of the United States to their foraging areas in the Northwest Atlantic (NWA) using carbon and nitrogen stable isotope values (δ13C and δ15N). We first evaluated the epidermis δ13C and δ15N values from 60 adult loggerheads with known foraging grounds. Twenty-two females from 6 nesting beaches and 23 males from one breeding area were tracked with satellite transmitters to identify their foraging locations following breeding, and 15 adult turtles were sampled at one foraging ground. Significant trends were observed between both δ13C and δ15N values of satellite-tracked loggerheads and the latitude of the foraging grounds to which the turtles migrated, reflecting a geographic pattern in the stable isotope values. Both δ13C and δ15N values characterized three geographic areas—with distinct abiotic and biotic features—used by adult loggerheads in the NWA. Discriminant analysis assigned all 375 female loggerheads to one of the three foraging areas; 91% were assigned with probabilities of ≥80%. The proportion of nesting turtles using each foraging ground varied geographically; most turtles nesting in northern beaches (72–80%) tend to forage at higher latitudes while most turtles nesting in southern beaches (46–81%) tend to forage at lower latitudes. Stable isotopes can reveal the foraging location of loggerhead turtles in the NWA, which will allow robust analyses of foraging ground effects on demography and improve the design of management strategies for the conservation of loggerhead populations. The conclusions and methods developed in this study are also relevant for other populations of sea turtles and for other highly migratory species.

to the editor: We would like to thank the scientists who commented on this Point:Counterpoint. We originally argued that high altitude is for the birds because of several unique features that should improve their ability to exercise at extremely high altitudes ([4][1]). Many authors agreed with our