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We present results of an inwater research program focusing on basic ecology of juvenile hawksbill turtles (Eretmochelys imbricata) in the Cayman Islands. We made 206 captures of 135 hawksbills in Little Cayman and 103 captures of 97 hawksbills in Grand Cayman. The Cayman Islands aggregation demonstrated a broad size distribution (20.5–62.6 cm straight carapace length), slow growth rate (3.0 ± 0.9 cm/y), and multiple recaptures, suggesting long-term residence in some individuals. Demonstrated home range was small (mean distance from capture to recapture 545 ± 514 m, range 2–2080 m); although, an international tag return suggested a long-range developmental migration. Vertical features provided important habitat in Little Cayman, and larger turtles were generally captured in deeper waters. Behavior at sighting varied by habitat: resting, swimming, and feeding were observed in coral reef, reef wall, and hardbottom colonized by sponges and gorgonians, and resting was frequently observed in uncolonize...

Co-management between local communities and government agencies is promoted as a strategy to improve fisheries management. This paper considers the potential for co-management of sea turtle fisheries within four UK Overseas Territories (OTs) in the Caribbean, and for co-ordinated management among those territories. We focus on fisher incentives for engaging in co-management and on the potential to scale up co-management to a regional level. This paper presents data from Anguilla, British Virgin Islands, Montserrat, and Turks and Caicos Islands, where 110 turtle fishers participated in a socio-economic survey undertaken as part of the ‘Turtles in the UK Overseas Territories in the Caribbean’ project. Based on three established criteria for co-management (perceived crisis in stock, willingness to participate and community cohesion), results suggest that fisher support for co-management exists within each OT, but the extent of support for and views of specific management interventions varies among OTs. The implications of results for co-management in each territory, and for establishing co-ordinated management regimes in the region, are discussed in the context of current debates about the nature of resources and scalar (mis)matches between resource and management regimes.

The population structure of the land crab Johngarthia lagostoma was studied on Ascension Island from 2005-2007, predominantly during the period of the seaward breeding migrations; approximately 4000 crabs were examined. Sex ratio varied according to location of sampling. Males predominated in permanent residential areas on high ground. Sexes were equal along migration routes to the sea. Females predominated in the breeding sites on the shore. Very few immature crabs (< 60 mm CW) were found. Males had modal and maximum sizes of 100-109 mm and 120 mm CW, females of 90-99 mm and 110 mm, respectively. An aging population is indicated. Crabs < 40 mm CW were all dark coloured, and colour variation into yellow, purple and intermediate morphs developed between 40-50 mm CW. Overall colour distribution of the population was 85% yellow, 5% intermediate, and 10% purple. Yellow morphs were more abundant in females (89%) than males (81%). The predominance of yellow morphs may be an adaptation to reduce heat st...

Here we present data from a 26-month program "Caribbean Turtle Watch," initiated as part of the "Turtles in the Caribbean Overseas Territories" (TCOT) program and designed to harness recreational divers to assess in-water populations of marine turtles in the Cayman Islands. We recorded 521 dives in Grand Cayman and Little Cayman between September 1, 2002 and November 29, 2003. Data, presented as the mean number of turtles sighted per dive, provide insight into spatiotemporal patterns of sightings as a proxy of abundance. Widespread sightings were recorded of two marine turtle species, green turtles Chelonia mydas and hawksbill turtles Eretmochelys imbricata, around both islands. There was no obvious relationship between the existence of Marine Protected Areas (MPAs) and the abundance of turtle sightings. Diving is allowed in Marine Park Zones and dive pressure may impact overall habitat quality in these areas. The vast majority of sightings of both species (94% in each case) were considered to be juvenile or subadults. While turtle sighting potential was not a major influence on dive site choice, actual turtle sighting greatly enhanced dive enjoyment. Spatiotemporal and morphological analyses of data collected by volunteers compared favorably with those based on data collected by scientists. This technique is transferable to other countries and may hold particular value in areas where resources assigned to marine turtle research are low.

Marine turtles are a taxon of world-wide conservation concern. Effective long-term monitoring is hampered by the fact that populations are widely dispersed except during the breeding season. Thus most monitoring programmes focus on nesting beaches, necessitating resource intensive studies, often over months, that could conceivably, be less comprehensive and focus on more parsimonious sampling. We analyse 11 years of exhaustive monitoring data for two species of Mediterranean marine turtles (Chelonia mydas and Caretta caretta). We resample using a variety of plausible sub-sampling regimens to estimate the total annual nesting population. We project our dataset into the future applying a range of population change rates to explore how adopting a monitoring programme based on sub-sampling would, for example, affect our ability to detect population decline. We show that accurate annual population estimates can be achieved with as few as 14 days of survey effort providing monitoring spans the peak of nesting. Furthermore, the modelled impact of sampling-based monitoring suggests that the duration to detect population change is not increased greatly. Our findings have implications for all marine turtle monitoring and have applicability to other animal groups. It is often considered desirable to perform exhaustive monitoring, with aversion of basing policy recommendations on partial data. However, comprehensive long-term monitoring programmes, particularly in developing nations, although presenting a number of advantages, are often impossible. Accurate total annual censuses can be achieved through a variety of sub-sampling regimens without sacrificing the ability to detect changes in the population trends over time. In this example, a solid block of at least 3 weeks sampling that encompasses the peak of the nesting season is advised.

As historically abundant spongivores, hawksbill turtles Eretmochelys imbricata likely played a key ecological role on coral reefs. However, coral reefs are now experiencing global declines and many hawksbill populations are critically reduced. For endangered species, tracking movement has been recognized as fundamental to management. Since movements in marine vertebrates encompass three dimensions, evaluation of diving behavior and range is required to characterize marine turtle habitat. In this study, habitat use of hawksbill turtles on a Caribbean coral reef was elucidated by quantifying diel depth utilization and movements in relation to the boundaries of marine protected areas. Time depth recorders (TDRs) and ultrasonic tags were deployed on 21 Cayman Islands hawksbills, ranging in size from 26.4 to 58.4 cm straight carapace length. Study animals displayed pronounced diel patterns of diurnal activity and nocturnal resting, where diurnal dives were significantly shorter, deeper, and more active. Mean diurnal dive depth (±SD) was 8 ± 5 m, range 2–20 m, mean nocturnal dive depth was 5 ± 5 m, range 1–14 m, and maximum diurnal dive depth was 43 ± 27 m, range 7–91 m. Larger individuals performed significantly longer dives. Body mass was significantly correlated with mean dive depth for nocturnal but not diurnal dives. However, maximum diurnal dive depth was significantly correlated with body mass, suggesting partitioning of vertical habitat by size. Thus, variable dive capacity may reduce intraspecific competition and provide resistance to degradation in shallow habitats. Larger hawksbills may also represent important predators on deep reefs, creating a broad ecological footprint over a range of depths.

We describe the results of extensive monitoring of leatherback turtle (Dermochelys coriacea) nesting in the Gulf of Uraba, Colombia and the Caribbean coast of southern Panama. On 100 km of coastline, we identified three important coastal stretches totalling 18.9 km that hold 98.5–98.7% of nesting activity. We estimated a total number of nesting activities at all sites of 6254 (2006) and 7509 (2007) and that 5689 (90.9%, 2006) and 6470 (86.2%, 2007) resulted in clutch deposition. Our data demonstrate that nesting levels in this region are much higher than had been previously been suggested. The Caribbean coast of Central America (Costa Rica, Panama, and Colombia) constitutes the fourth largest nesting aggregation for this species in the world after the Guianas (French Guiana and Suriname in South America), Gabon (West Africa) and Trinidad (Caribbean). Estimated nest survival showed strong inter-site differences, ranging from 23% to 75% and, if hatchling production is to be augmented, different management strategies will be needed at each site. Perhaps more importantly, our findings highlight that despite the intense conservation interest in this species for several decades, there are still major gaps in status information and there is a need for increased rigor in the extent of spatial coverage of baseline monitoring to effectively inform conservation assessments. We must guard against precise yet spatially limited estimates of small parts of populations leading to an inaccurate picture of overall status.

We present the result of a multi-annual assessment of the spatio-temporal patterns of marine turtle nesting, and foraging in the Eastern Caribbean archipelago state of the British Virgin Islands. Despite exploitation over several centuries, three species (leatherback Dermochelys coriacea, green Chelonia mydas and hawksbill Eretmochelys imbricata turtles) are still nesting and green and hawksbill turtles are found foraging. Leatherback turtles are showing signs of a recovery co-incident with the implementation of an effective moratorium on adult take. When compared with historical data we demonstrate an apparent reduction in nesting levels in green and hawksbill turtles and a nesting range contraction in green turtles. Despite current conservation steps, it will be a decade or more before evidence of recovery can be expected in the two hard-shelled species. Coupled with wider biological knowledge, our findings offer insights into the relative resilience of the different species to exploitation pressure. Additionally, the intra-annual temporal and spatial spread of nesting demonstrated underlines the difficulties of monitoring such a multi-species assemblage in such a diffuse archipelago.

As marine turtles traverse entire ocean basins, a number of techniques have been developed to gather information on their movements at sea. These range from basic methods, such as mark and recapture using flipper tags, to more technically advanced, expensive approaches, such as satellite tracking. Here we report the first published use of geolocation by light, using global location sensing (GLS) units, to estimate the locations of marine turtles in the Mediterranean. We attached units to 9 green Chelonia mydas and 3 loggerhead Caretta caretta turtles which had nested in Cyprus in previous years. One individual of each species was also fitted with a satellite transmitter for comparison. GLS units were retrieved on subsequent visits made by instrumented turtles during the same nesting season. In total, 28 GLS units were recovered from 12 individuals. The mean great-circle distance between the mean daily position calculated from satellite tracking and the corresponding mean light-based geolocation over the same time period was 50.3 km for green turtles and 57.6 km for loggerhead turtles. We suggest that GLS technology offers potential utility for identifying large-scale movements, migratory pathways, and over-wintering or foraging sites of adult female marine turtles.

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.

The Red List of Threatened Species, produced by the International Union for the Con- servation of Nature and Natural Resources/World Conservation Union (IUCN) classifies the global populations of all 7 sea turtle species, except the flatback Natator depressus, as Endangered or Crit- ically Endangered. However, the IUCN Marine Turtle Specialist Group (MTSG), which carries out the assessments for the IUCN, is experiencing internal debate over the relevance and usefulness of such statements. Assigning a distinct Red List category to the global population, as a single manage- ment unit, does not capture the reality of regional and local populations that tend to have different (positive or negative) trajectories. From a technical viewpoint, setting the time scale for assessment at 3 generations, which is 60 to 100+ yr for sea turtles, means few reference points are available for quantifying past changes in abundance. Moreover, it hardly establishes a sense of urgency for action to prevent future changes over long time scales. The application of current Red List criteria, resulting in flawed categorizations, creates problems of credibility. When a species that may number in the mil- lions in an ocean basin is classified as being at the same 'very high risk of extinction in the wild,' as a species represented by just a few individuals, there is something fundamentally wrong with the assessment system. We suggest that MTSG members desist from using the current Red List criteria to generate implausible global assessments of extinction risk and instead concentrate their efforts on developing more realistic and credible criteria, perhaps for application at the regional level.

In 2006, we tracked a single Green Turtle after nesting Latakia, providing the first evidence of foraging grounds and migratory routes from this rookery which is one of the most important nesting areas in the Mediterranean. Tracking lasted 95 days during which time the turtle migrated southward (minimum average speed=0.9 km/h) and then westward (minimum average speed=1.6 km/h), following the coast. The turtle settled in the Bay of As Sallum, western Egypt where it remained in neritic, coastal waters for the final 26 days of transmissions. These results, when combined with findings from Cyprus, Turkey and Greece, further highlight the importance of the North African coast for foraging adult turtles and the need for effective conservation measures to be adopted there.

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.

Identifying key marine megavertebrate habitats has become ever more important as concern increases regarding global fisheries bycatch and accelerated climate change. This will be aided by a greater understanding of the patterns and processes determining the spatiotemporal distribution of species of conservation concern. We identify probable foraging grounds for leatherback turtles in the NE Atlantic using monthly landscapes of gelatinous organism distribution constructed from Continuous Plankton Recorder Survey data. Using sightings data (n = 2013 records, 1954 to 2003) from 9 countries (UK, Ireland, France, Belgium, The Netherlands, Denmark, Germany, Norway and Sweden), we show sea surface temperatures of approximately 10 to 12 degree C most likely indicate the lower thermal threshold for accessible habitats during seasonal foraging migrations to high latitudes. Integrating maps of gelatinous plankton as a possible indicator of prey distribution with thermal tolerance parameters demonstrates the dynamic (spatial and temporal) nature of NE Atlantic foraging habitats. We highlight the importance of body size- related thermal constraints in structuring leatherback foraging populations and demonstrate a latitudinal gradient in body size (Bergmann's rule) where smaller animals are excluded from higher latitude foraging areas. We highlight the marine area of the European continental shelf edge as being both thermally accessible and prey rich, and therefore potentially supporting appreciable densities of foraging leatherbacks, with some suitable areas not yet extensively surveyed.

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.

Trials were carried out in the Shannon estuary, Ireland, to test the effects of continuous (CPs) and responsive pingers (RPs) on bottlenose dolphin behaviour. In controlled trials, active and control pingers were deployed on fixed moorings, with T-PODs—acoustic monitoring devices to detect cetacean activity. In a separate trial, pingers were deployed from a moving boat which actively located dolphin groups in the estuary, and dolphin behaviour was recorded. In the static trials, overall detection rates of dolphin vocalizations on the T-POD were significantly lower in the presence of active CPs, but this was not the case for RPs. Mean inter-click interval values were longer for click trains produced in the presence of inactive RPs than for active RPs, active or inactive CPs. In boat-based trials, both active CPs and RPs appeared to affect bottlenose dolphin behaviour, whereby dolphins immediately left the area at speed and in a highly directional manner, involving frequent leaps.

Historically, nesting marine turtles were abundant in the Cayman Islands and were an integral part of the economy and culture. Today, nesting of loggerhead turtle Caretta caretta and green turtles Chelonia mydas takes place at very low levels. Hawksbill Eretmochelys imbricata nesting has not been recorded since 1999. We overview highly detailed monitoring data gathered over a 6-year period allowing insight into the magnitude and spatial and temporal patterns of marine turtle nesting, cost-effectiveness of monitoring such reduced populations, impacts of development on reproductive success and current threats to the recovery of the population. Nesting is diffuse and widely distributed for both nesting species on Grand and Little Cayman. Modelled nesting detection profiles for Grand Cayman show that in order to maintain data resolution, most sandy coastline must be surveyed throughout each season. However, in Little Cayman it may be possible to reduce effort. Legal take of adults and illegal take of eggs may be significantly impacting the remaining population. Surprisingly, we observed no significant correlation between density of coastal development and clutch density, adult emergence success or hatching success for either species. A significant relationship exists however, between density of coastal development and incidence of misorientation events in loggerhead hatchlings but not in green turtle hatchlings. Effective protection of known nesting habitat and the elimination of exploitation of remaining adults and eggs within the population are critical to its recovery.

In species of conservation concern it is often difficult to be certain that population diver- sity and structure have been adequately characterised by genetic sampling. Since practical and financial constraints tend to be associated with increasing sample sizes in many conservation genetic studies, it is important to consider the potential for sampling error and bias due to inadequate sam- ples or spatio-temporal structure within populations. We analysed sequence data from the mitochon- drial DNA control region in a large sample (n = 245) of green sea turtles Chelonia mydas collected at the globally important rookery of Ascension Island, South Atlantic. We examined genetic diversity and structure among 10 sampling sites, 4 beach clusters and 4 nesting seasons, and evaluated the genetic composition of Ascension against other Atlantic nesting populations, including the well- studied rookery at Tortuguero (Costa Rica). Finally, we used rarefaction and GENESAMP analyses to assess the ability of different sample sizes to provide acceptable genetic representations of a popula- tion, using Ascension and Tortuguero as models. On Ascension, we found 13 haplotypes, of which only 3 had been previously observed in the rookery, and 5 previously undescribed. We detected no differentiation among beach clusters or sampling seasons, and only weak differentiation among the 3 primary nesting sites. The increased sample size for Ascension provided higher resolution and statistical power in describing genetic structure among all other known Atlantic rookeries. Our extrapolations showed that a maximum of 18 and 6 haplotypes are expected to occur in Ascension and Tortuguero, respectively, and that current sample sizes are sufficient to describe most of the vari- ation. We recommend using rarefaction and GENESAMP analyses on a rookery-by-rookery basis to evaluate whether a sample set adequately describes mitochondrial DNA diversity, thus strengthen- ing subsequent phylogeographic and mixed stock analyses, and management recommendations for conservation.

The avifauna of the British Virgin Islands (BVI) has received little attention from researchers. The lack of baseline information is therefore a major hindrance to the construction of management plans. Here we present detailed monitoring data on the species composition and numbers of each species for the island of Anegada, BVI. We surveyed the birds of Anegada between November 2003 and March 2005 utilising a combination of coastal transects, wetland bird counts, point counts, and species-specific survey methods for nocturnal species. A total of 99 different species were recorded, with a large increase in the number of species and number of individuals centred around peak migration in September. Although there is a depauperate terrestrial bird community consisting of predominately generalist species, it holds important populations of regional avifauna. For example, it hosts five regionally important breeding seabird colonies and its wetlands provide an important stop-over and over-wintering site for many species of shorebirds and waterbirds. In addition, the Eastern salt ponds are also the only breeding site for the greater flamingo, Phoenicopterus ruber, within the territory. We discuss our findings within the current framework of regional conservation and provide recommendations for the implementation of a territory wide monitoring program as a first step towards meeting the UK's commitments under several multilateral environmental agreements.

International audience; To refine our understanding of the spatial structure of the green turtle (Chelonia mydas) populations in the South West Indian Ocean (SWIO), we analysed patterns of mitochondrial DNA (396 base pairs control region fragment) variation among 171 samples collected at five distinct locations (Kenya, Northern Mozambique, and three locations in the Republic of Seychelles: the Granitic, Amirantes, and Farquhar groups) and compared them to genetic data (n = 288), previously collected from 10 southern locations in the SWIO. We also analysed postnesting satellite tracks (n = 4) from green turtles nesting in the Amirantes group. Pairwise comparisons of haplotype frequencies showed significant genetic differentiation amongst rookeries and suggest that the SWIO hosts two main genetic stocks of nesting green turtles that could themselves be divided in two sub-stocks that still need to be confirmed: A. the Southern Mozambique Channel, that could be composed of two sub-stocks (a1) Europa and (a2) Juan de Nova, and B. the Northern SWIO (N-SWIO) comprising two sub-stocks (b1) the Seychelles archipelago stock—SEY; and (b2) the remaining Northern SWIO rookeries. The newly revealed differentiation of the Seychelles population is supported by restricted migration of females tracked from the Amirantes group suggesting relatively limited links with other regional stocks. We hypothesize that this differentiation could be due to local and regional current patterns and to the role of the Indo-Pacific Barrier as a genetic break, enhanced during periods of sea level decrease associated with a rare but continuous flow of hatchlings and young juveniles from Western Australia.

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.

Disease in wildlife populations is often controlled through culling. But when healthy individuals are removed and diseased individuals are left in the population, it is anticipated that prevalence of disease increases. Although this scenario is presumably common in exploited populations where infected individuals are less marketable, it is not widely reported in the literature. We describe this scenario in a marine turtle fishery in the Turks and Caicos Islands (TCI), where green turtles are harvested for local consumption. During a 2-year period, we recorded the occurrence of fibropapillomatosis (FP) disease in green turtles (Chelonia mydas) captured during in-water surveys and compared it with that of turtles landed in the fishery. 13.4% (n = 32) of turtles captured during in-water surveys showed externally visible signs of FP. FP occurred at specific geographic locations where fishing also occurred. Despite the disease being prevalent in the size classes selected by fishers, FP was not present in any animals landed by the fishery (n = 162). The majority (61%) of fishers interviewed expressed that they had caught turtles with FP. Yet, 82% of those that had caught turtles with the disease chose to return their catch to the sea, thereby selectively harvesting healthy turtles and leaving those with the disease in the population. Our study illustrates that fisher choice may increase the prevalence of FP disease and highlights the importance of this widely neglected driver in the disease dynamics of exploited wildlife populations.

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 Michoacán (1337-2928 km). In addition, three post-nesting females were satellite tracked from Colola beach, Michoacán 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 longdistance 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. Fil: Hart, Catherine E.. University Of Exeter; Reino Unido Fil: Blanco, Gabriela Silvina. Drexel University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: Coyne, Michael S.. University Of Exeter; Reino Unido. SEATURTLE.org; Estados Unidos Fil: Delgado Trejo, Carlos. Universidad Michoacána de San Nicolas de Hidalgo. Instituto de Investigaciones sobre los Recursos Naturales; México Fil: Godley, Brendan J.. University Of Exeter; Reino Unido Fil: Jones, T. Todd. Pacific Islands Fisheries Science Center; Estados Unidos Fil: Resendiz, Antonio. Secretaria de Medio Ambiente y Recursos Naturales. Dirección General de Vida Silvestre. Instituto Nacional de Ecología; México Fil: Seminoff, Jeffrey A.. Southwest Fisheries Science Center; Estados Unidos Fil: Witt, Mathew. University Of Exeter; Reino Unido Fil: Nichols, Wallace J.. California Academy of Sciences; Estados Unidos

We present data spanning approximately 100 years regarding the spatial and temporal occurrence of marine turtle sightings and strandings in the northeast Atlantic from two public recording schemes and demonstrate potential signals of changing population status. Records of loggerhead (n = 317) and Kemp’s ridley (n = 44) turtles occurring on the European continental shelf were most prevalent during the autumn and winter, when waters were coolest. In contrast, endothermic leatherback turtles (n = 1,668) were most common during the summer. Analysis of the spatial distribution of hard-shell marine turtle sightings and strandings highlights a pattern of decreasing records with increasing latitude. The spatial distribution of sighting and stranding records indicates that arrival in waters of the European continental shelf is most likely driven by North Atlantic current systems. Future patterns of spatial-temporal distribution, gathered from the periphery of juvenile marine turtles habitat range, may allow for a broader assessment of the future impacts of global climate change on species range and population size.

Historically, marine turtle populations have been an important natural resource for people in the Caribbean region and have been subject to various levels of harvest for millennia. 4 Turtle meat an...

The emergence patterns of green turtle (Chelonia mydas) hatchlings on two beaches on Ascension Island, South Atlantic were monitored and related to thermal patterns in the sand at 10, 20, 30 and 40cm depth. A total of 6001 hatchlings were recorded emerging on Long Beach, and 3171 emerged on North East Bay during the study period. No significant difference was observed in the temporal pattern of hatchling emergence among nights, or between the two beaches. Hatchling emergence predominantly occurred at night with over 93% of hatchlings emerging during the hours of darkness. Almost all hatchlings emerging in daylight suffer predation by the Ascension frigatebird (Fregata aquila). Counts of frigatebirds both above the study beaches and offshore were highest just after sunrise, with a smaller peak prior to sunset, when frigatebirds were found to predate hatchlings emerging, crawling down the beach or detected in inshore waters. The likely thermal cues controlling hatchling emergence were investigated (temperature at different depths, thermal gradients in the sand and temperature change). The most plausible thermal factor appears to be the change of temperature at superficial sand depths, with hatchling emergence inhibited when subsurface sand temperatures were increasing. This simple mechanism is likely to ensure predominantly nocturnal hatchling emergence regardless of sand albedo, seasonality or latitude as long as night is relatively cooler than day.

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.

We analysed the genetic structure of seven nesting sites of the endangered green turtle (Chelonia mydas) in Africa using mitochondrial DNA control region sequences. Tissue samples were collected from 188 nesting females at six sites in West Africa and one in the Indian Ocean. A 488 bp fragment of the control region revealed 14 different haplotypes, 10 of which are previously undescribed. The most common haplotype (CM8) was observed in 157 individuals. All other haplotypes were closely related, except two divergent lineages: CM38, removed by four substitutions, and the three Indian Ocean haplotypes, distinguished by 31 substitutions. Significant differences in haplotype and nucleotide diversity were observed between Atlantic rookeries and among ocean basins. Analysis of molecular variance revealed high levels of differentiation between the Atlantic and the Indian Ocean populations but a much shallower Atlantic substructuring. Green turtle population genetic structure is thought to have been shaped by a dynamic succession of extinction and recolonisation of rookeries, by natal homing and occasional breakdown in nest-site fidelity. Mismatch distributions of pairwise differences between haplotypes at each rookery were found to be consistent with recent population expansion. We argue that demographic histories can be explained by scenarios at several temporal scales, including geological events, sea level fluctuations and more recent patterns of exploitation. We discuss management and conservation implications of our results for these threatened populations, identifying two ESUs (one in the Atlantic and one in the Indian ocean) and three MUs within the Atlantic.

Caribbean seabirds are subject to numerous threats, and population levels are thought to be at a fraction of historical levels. Despite being a well-known taxonomic group there is still a paucity of data for most seabird species on many of the Caribbean islands. We carried out detailed surveys of the seabird breeding populations in the British Virgin Islands (BVI) during the breeding seasons of 2004 and 2005. We surveyed 42 different islands and cays over the 2 yr with 60 and 63% of these having at least one breeding seabird species in 2004 and 2005, respectively. A total of 15 spe- cies of breeding seabird was recorded, one of which, the gull-billed tern Sterna nilotica, was pre- viously thought to have been extirpated. Two species, roseate tern Sterna dougallii and magnificent frigatebird Fregata magnificens, had globally significant colonies in the BVI and a further 8 species had a regionally significant population in the BVI. We discuss our findings within a global and regional conservation context and provide recommendations for ensuring the continued existence of BVI seabird populations.

We present detailed results of a satellite tracking project following 10 adult female tur- tles from the Cayman Islands, thought to have once been one of the world's largest rookeries. By tracking the movements of 7 green turtles Chelonia mydas and 3 loggerhead turtles Caretta caretta from now critically reduced rookeries we defined key habitats for internesting movement, migration, and foraging in a range of Caribbean jurisdictions. Turtles tracked from the Cayman Islands traveled to foraging grounds in Belize, Guatemala, Honduras, Mexico, Nicaragua and the USA. This range encompasses a >2000 km stretch of Caribbean coastline and the Florida Keys, highlighting the need for international cooperation in identifying and mitigating foraging ground threats. For one of the green turtles, foraging site fidelity was elucidated over the course of two reproductive seasons, and oceanic internesting intervals/post-nesting oceanic circles were defined for the first time in Atlantic loggerhead turtles. In addition to fundamental and applied insights into the biology of the 2 species, this research elucidates geographic scale for potential ecological effects of past decimation of rook- eries in the Cayman Islands and highlights the effectiveness of community efforts in support of conservation research.

Many marine turtle populations are smaller than they once were, having been exploited at varying levels since prehistory. However, in areas where exploitation of adults has been substan- tially reduced or halted, increases in local nesting populations of several species have been shown. There is a paucity of published information on catch rates, methodologies, target species and size classes in small scale marine turtle fisheries. In the Cayman Islands a legal, highly regulated turtle fishery exists; laws regarding turtle protection regulate seasonality, capture location and method, size class, and levels of take via a licensing system. Licenses have only been issued to 'traditional' fishermen and will not be issued to other individuals in the future. Analysis of fishery data from legally captured animals (n = 27) shows that all turtles reported as captured were either adults or very large juveniles, and many were captured during periods when adults were likely to have been in the waters of the Cayman Islands to breed. We conclude that, given the critically small size of the local nesting populations, it is possible that this directed take, although at very low levels in regional terms, may impede the local population recovery sought through other conservation and manage- ment steps being taken in the Cayman Islands.

Aim To examine the exploitation, recovery and current status of green turtles (Chelonia mydas) nesting at Ascension Island. Location Ascension Island (UK) (7°57′ S, 14°22′ W), South Atlantic Ocean. Methods We analysed records of the harvest of green turtles nesting at Ascension Island between 1822 and 1935, illustrating the decline in numbers over this period. Using a deterministic age-class structured model we predict the initial number of breeding females present in the population prior to the recorded harvest and compare this to our estimate of the current population based upon our recent annual surveys (1999–2004). Results Prior to 1822 we estimate the nesting population of green turtles to have been at least 19,000–22,000 individuals in order for the population to have survived the level of harvest recorded. From recent data (1999–2004), we estimate the current breeding population of green turtles at this site to be 11,000–15,000 females. Our results illustrate a dramatic recovery of the population, which is still increasing exponentially and shows no evidence of slowing, suggesting it has not reached 50% of its carrying capacity. Main conclusions We estimate that, since the 1970s, the Ascension Island population of green turtles has increased by 285% and question the recent listing of this species as endangered by the IUCN (World Conservation Union), in particular in the Atlantic Ocean, where 75% of the populations assessed by the IUCN are increasing. Indeed, we estimate the global population of this species to be in excess of 2.2 million individuals. We suggest that the IUCN's global listing process detracts attention from those populations that are truly threatened with extinction and should not, in its present form, be applied to globally distributed long-lived species such as marine turtles.

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.

Despite the obvious power and advan- tages of the Argos system to track animals by satellite, the data generated are difficult for many biologists to exploit. A broad range of skills is required to efficiently download, collate, filter and interpret Argos data. Inte- gration of animal movements with other physical (e.g. remote sensing imagery) and anthropogenic (e.g. fish- ery distributions) datasets presents additional technical and computing challenges. The Satellite Tracking and Analysis Tool (STAT) is a freely available system de- signed for biologists who work on animal tracking; it includes a set of standardized tools and techniques for data management, analysis, and integration with envi- ronmental data. STAT logs in to the Argos computer network each day and downloads all available loca- tions and associated data for each user. These data are parsed and stored in a relational database and auto- matically backed up to an offsite location. A number of data filtering options are available, including setting maximum speed, time or distance between consecutive points, Argos location class, and turning angle. A vari- ety of environmental data layers, including bathymetry, sea surface temperature, sea surface height, ocean cur- rents and chlorophyll, can be sampled for all locations in the STAT database and can be downloaded and incorporated into tracking maps and animations. STAT also facilitates collaboration and the sharing of animal tracking information with the wider public and funding organizations. We hope that STAT will act as a catalytic foundation, fostering collaboration among users of satellite telemetry, and ensuring maximum value from these studies.

The emergence patterns of both green (Chelonia mydas) and loggerhead (Caretta caretta) turtle hatchlings were observed in great detail over three seasons at Alagadi beach, northern Cyprus. In total, 38 green turtle and 50 loggerhead turtle nests were monitored, accounting for the emergence of 2,807 and 2,259 hatchlings, respectively. We quantified these emergences into 397 green turtle and 302 loggerhead turtle emergence groups. Overall, 85.0% of green turtle and 79.5% of loggerhead turtle groups emerged at night; these accounted for 85.5 and 90.8% of hatchlings, respectively. The remaining emergences were dispersed throughout the day for green turtle nests but confined to the morning in loggerhead turtle nests. Hatchling emergence from individual nests occurred over periods of between 1 and 7 nights, with most hatchlings typically emerging on the first night. Group sizes of green turtles emerging during the day were significantly smaller than those emerging at night. Hatchlings of both species that emerged from nests during the day had longer emergence durations than those that emerged from nests at night only.

The effect of high ambient temperatures on the behaviour of Magpies (Pica pica) was assessed in northern Cyprus, which marks the southern limit of their European range. Magpies actively selected their thermal environment when temperatures rose above 31°C, by retreating to shaded areas. On days when the temperature was higher, Magpies appeared to spend more time perched in the shade and less time foraging. Flying and foraging activities were generally restricted to cooler parts of the day. Magpies were rarely seen panting or drinking and gular fluttering was not observed. We suggest that utilisation of shade is important for Magpies to regulate their body temperature, allowing them to remain common at the southern limit of their range despite experiencing high temperatures.

Sea turtles are known to perform long-distance, oceanic migrations between disparate feeding areas and breeding sites, some of them located on isolated oceanic islands. These migrations demonstrate impressive navigational abilities, but the sensory mechanisms used are still largely unknown. Green turtles breeding at Ascension Island perform long oceanic migrations (>2200 km) between foraging areas along the Brazilian coast and the isolated island. By performing displacement experiments of female green turtles tracked by satellite telemetry in the waters around Ascension Island we investigated which strategies most probably are used by the turtles in locating the island. In the present paper we analysed the search trajectories in relation to alternative navigation strategies including the use of global geomagnetic cues, ocean currents, celestial cues and wind. The results suggest that the turtles did not use chemical information transported with ocean currents. Neither did the results indicate that the turtles use true bi-coordinate geomagnetic navigation nor did they use indirect navigation with respect to any of the available magnetic gradients (total field intensity, horizontal field intensity, vertical field intensity, inclination and declination) or celestial cues. The female green turtles successfully locating Ascension Island seemed to use a combination of searching followed by beaconing, since they searched for sensory contact with the island until they reached positions NW and N of the Island and from there presumably used cues transported by wind to locate the island during the final stages of the search.

A comparison of body size and flipper size was carried out on green turtle (Chelonia mydas) hatchlings produced from natural nests at two beaches on Ascension Island, South Atlantic and one beach in northern Cyprus in the Mediterranean (N=18 nests; N=180 hatchlings). Hatchlings from Ascension Island were significantly larger and heavier than hatchlings in Cyprus, a likely consequence of maternal size effects. Incubation temperature appeared to influence body size of hatchlings on Ascension Island with higher temperatures producing smaller hatchlings. Both hind and fore-flipper area scaled positively with body size. In proportion to body size, hind-flipper area appears relatively consistent among the Atlantic populations but is smaller than hatchlings measured in Hawaii.

Sea turtles show temperature dependent sex determination. Using an empirical relationship between sand and air temperature, we reconstructed the nest temperatures since 1855 at Ascension Island, a major green turtle (Chelonia mydas) rookery. Our results show that inter-beach thermal variations, previously ascribed to the albedo of the sand, which varies hugely from one beach to another, have persisted for the last century. Reconstructed nest temperatures varied by only 0.5 °C on individual beaches over the course of the nesting season, while the temperature difference between two key nesting beaches was always around 3 °C. Hence inter-beach thermal variations are the main factor causing a large range of incubation temperatures at this rookery. There was a general warming trend for nests, with a mean increase in reconstructed nest temperatures for different months of between 0.36 and 0.49 °C for the last 100 years.

Most marine turtle species are non-annual breeders and show variation in both the number of eggs laid per clutch and the number of clutches laid in a season. Large levels of inter-annual variation in the number of nesting females have been well documented in green turtle nesting populations and may be linked to environmental conditions. Other species of marine turtle exhibit less variation in nesting numbers. This inter-specific difference is thought to be linked to trophic status. To examine whether individual reproductive output is more variable in the herbivorous green turtle (Chelonia mydas Linneaeus 1758) than the carnivorous loggerhead (Caretta caretta Linneaeus 1758), we examined the nesting of both species in Cyprus over nine seasons. Green turtles showed slower annual growth rates (0.11 cm year−1 curved carapace length (CCL) and 0.27 cm year−1 curved carapace width (CCW)) than loggerhead turtles (0.36 cm year−1 CCL, 0.51 cm year−1 CCW). CCL was highly correlated to mean clutch size in both green (R2=0.51) and loggerhead turtles (R2=0.61) and maximal clutch size of green turtles (R2=0.58). Larger females did not lay a greater number of clutches or have a shorter remigration interval than smaller females of either species. On average, the size of green turtle clutches increased and that of loggerhead turtles decreased as the season progressed. Individual green turtles, however, produced more eggs per clutch through the season to a maximum in the third or fourth clutch. In loggerhead turtles, clutches 1–4 were very similar in size but the fifth clutch was 38% smaller than the first. No individuals of either species were recorded laying more than five clutches. Green turtles may not be able to achieve their maximum reproductive output with respect to clutch size throughout the season, whereas only loggerhead turtles laying five clutches (n=5) appear to become resource depleted. Green turtles nesting in years when large numbers of nests were recorded laid a greater number of clutches than females nesting in years with lower levels of nesting.

Two female loggerhead turtles (Caretta caretta) were tracked, following nesting at Alagadi Beach (35°33′N, 33°47′E), Northern Cyprus, eastern Mediterranean for 60 and 82 days, respectively. The two individuals showed marked differences in their behaviour. Individual A was tracked to Syrian coastal waters, whereas individual B travelled around the coast of Northern Cyprus to a foraging site in the waters off the east coast of Northern Cyprus. Submergence durations varied markedly during different phases of the migration, suggesting coastal foraging/resting at certain stages en route with sustained directed travelling movements during initial coastal movements and open ocean crossing. Both turtles showed fidelity to foraging grounds for the duration of transmissions (Turtle A: 36 days; Turtle B: 58 days). In both cases, locations were centred in inshore waters although the two individuals exhibited quite different submergence patterns. Individual A carried out very short dives of typical duration 20 min. Diel differences in submergence duration at the foraging grounds suggested longer dives at night/early morning for both turtles. For Turtle A, there was a general reduction in submergence duration as the period of residence increased; a pattern that may have been related to increasing temperature experienced. The total distance travelled by the two turtles (320 and 227 km) was relatively short when compared to satellite tracking studies of conspecifics following nesting in South Africa and USA and tagging studies of nesting loggerhead turtles in Greece and Australia. It is hypothesized that short migratory distance may be correlated with both the small body size and the relatively high frequency of remigration in this population.

Long-term records of nesting numbers, or proxies to nesting numbers, show a precipitous decline in the size of many sea turtle populations. Population declines are most frequently attributed to fisheries bycatch, although direct quantification of this level of mortality is rare. We used satellite-tracking records for turtles in the Mediterranean Sea and Pacific, Atlantic and Indian Oceans to identify when turtles had been captured. Evidence for capture came from a combination of an increase in good quality locations from transmitters, transmitters moving inland to coastal towns and villages, and on-board submergence data, showing that transmitters had come out of the water. A high level of mortality was calculated, confirming current concerns regarding the outlook for sea turtles.

The movements of 8 green turtles Chelonia mydas in Brazilian coastal waters were tracked using transmitters linked to the Argos system for periods of between 1 and 197 d. These were the first tracking data gathered on juveniles of this species in this important foraging ground. Infor- mation was integrated with that collected over a decade using traditional flipper-tagging methods at the same site. Both satellite telemetry and flipper tagging suggested that turtles undertook 1 of 3 general patterns of behaviour: pronounced long range movements (>100 km), moderate range move- ments (

Sea turtles have recently been shown to have the sensory ability to use magnetic information for guidance in the open ocean, although the importance of different potential navigational cues remains unknown. Between May and August 2001, we satellite-tracked green turtles, Chelonia mydas, during their >2000-km postnesting migration from Ascension Island to Brazil, following five individuals both during their transoceanic crossing and while on the Brazilian coast. None of the turtles travelled directly to its final destination but, instead, there were extended (up to 792 km) movements along the coast after the oceanic crossings. The extent of movement along the coast was unrelated to the oceanic crossing route. For example, individuals whose final destination was in the north of Brazil did not follow a more northerly oceanic crossing than those with a more southerly final destination. These observations show that green turtles returning from Ascension Island do not swim directly to their final destination, but instead conduct migration in two distinct phases: a fairly direct open ocean crossing, following which they turn north or south along the coast to reach their final destination. This long-distance migration may therefore be conducted without turtles needing to resort to sophisticated navigational skills. These previously unidentified long coastal movements may heighten the risk of turtles being captured by fishermen.

We used time-depth recorders to measure depth utilisation in gravid green turtles (Chelonia mydas) during the internesting period at northern Cyprus (Mediterranean), a nesting area where individuals feed, and at Ascension Island (mid-Atlantic), a nesting area where individuals fast. There were contrasting patterns of depth utilisation between the two sites, illustrating that the behaviour of this species is shaped by local conditions. For example, the amount of time spent shallower than 4 m was 90% at Cyprus but only 31% at Ascension Island, and there was a clear difference between the mean depth at Cyprus (2.7 m, n=9 internesting intervals) versus Ascension Island (9.5 m, n=6 internesting intervals) (t 5=5.92, P=0.002). At Cyprus, turtles spent the greatest percentage of their time at very shallow depths, where surveys reveated a high abundance of seagrass on which this population feeds. In contrast, the deeper distribution at Ascension Island may reflect the preferred depth for resting on the seabed.

Temperature loggers were attached to the carapace of green turtles (Chelonia mydas) at Ascension Island and Cyprus and to loggerhead turtles (Caretta caretta) at Cyprus, in order to record the ambient temperature experienced by individuals during the internesting interval, i.e. the period between consecutive clutches being laid. Internesting intervals were relatively short (10–14 days) and mean ambient temperatures relatively warm (27–281C), compared to previous observations for these species nesting in Japan, although a single internesting interval versus temperature relationship described all the data for these two species from the different areas. The implication is that water temperature has both a common and a profound effect on the length of the internesting interval for these two species: internesting intervals are shorter when the water is warmer. r 2002 Elsevier Science Ltd. All rights reserved.

Most species of marine turtle breed every two or more years and it is the norm for females to lay more than one clutch of eggs within a nesting season. Knowing the interval between breeding seasons and the clutch frequency (number of clutches laid by an individual in a breeding season) of females allows us to assess the status of a nesting population. At Alagadi Beach, Northern Cyprus, over a period of 6 years (1995–2000), we attributed 96% of green Chelonia mydas and 80% of loggerhead Caretta caretta turtle clutches to known individual females. This intensive level of monitoring enabled us to estimate the clutch frequency for both species. Using four different methods we estimated clutch frequency to be 2.9–3.1 clutches per female for green turtles and 1.8–2.2 clutches per female for loggerhead turtles. The median interval between nesting seasons for green turtles was 3 years, and for loggerhead turtles it was 2 years. Utilizing these parameters and available data from other beaches that are monitored regularly, we estimate that there are 2,280–2,787 logger-head and 339–360 green turtles nesting annually at these sites in the Mediterranean. This highlights the Critically Endangered status of this population of green turtles. Furthermore, as conventional beach patrols underestimate clutch frequency, these population estimates are likely to be optimistic.

Female green sea turtles (Chelonia mydas) nesting at Ascension Island (7°57'S, 14°22'W) in the middle of the Atlantic Ocean had a mean body mass (post oviposition) of 166.3 kg (range 107.5–243.5 kg, n = 119). Individuals lost mass slowly during the nesting season (mean mass loss 0.22 kg·d–1, n = 14 individuals weighed more than once). Gut-content analysis and behavioural observations indicated a lack of feeding. Females of equivalent-sized pinniped species that also do not feed while reproducing (nursing pups) on islands lose mass about 17 times faster. This comparatively low rate of mass loss by green turtles probably reflects their ectothermic nature and, consequently, their low metabolic rate. We estimate that a female turtle would lose only 19% of her body mass during the 143-day, 4400-km round trip from Brazil if she did not eat, laid 3 clutches of eggs, and lost 0.22 kg·d–1.

There is a relative paucity of data regarding the at-sea distribution and behaviour of marine turtles. This is especially true for the critically endangered green turtle Chelonia mydas population in the Mediterranean. Six adult female green turtles were equipped with satellite transmitters and tracked for periods of between 28 and 293 d following their final nesting of the season in northern Cyprus. Data elucidated hitherto unknown migratory pathways and highlighted the importance of North African coastal waters as feeding habitat for adults of this species. For three individuals, instruments transmitted detailed information on dive depth, dive duration and water temperature which afforded novel insights into behaviour during different stages of migration, feeding in the foraging grounds and most remarkably, during a period of midwinter diapause when water temperatures were generally below 25°C. Turtles showed fidelity to specific shallow inshore feeding areas and moved offshore to deeper wintering sites.

Time depth recorders were used to assess the patterns of depth utilisation by 2 logger- head turtles Caretta caretta in Cyprus, eastern Mediterranean. Dives to the seabed accounted for 59% (171 h) and 75% (215 h) of the internesting interval, respectively, with most dives being shallow (