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Sea turtles are considered as bio-indicators for monitoring the efficiency of restoration measures to reduce marine litter impacts on health. However, the lack of extended and standardised empirical data has prevented the accurate analysis of the factors influencing litter ingestion and the relationships with individual health. Historic data collected from 1988 and standard data collected from 2016 were harmonised to enable such analyses on necropsied loggerhead turtles (Caretta caretta) in eight Mediterranean and North-East Atlantic countries. Litter was found in 69.24 % of the 1121 individuals, mostly single-use and fishing-related plastics. Spatial location, sex and life history stage explained a minor part of litter ingestion. While no relationships with health could be detected, indicating that all individuals can be integrated as bio-indicators, the mechanistic models published in literature suggest that the high proportion of plastics in the digestive contents (38.77 % per individual) could have long-term repercussions on population dynamics. © 2022

Coastal waters of the Valencia region are important habitats for bottlenose dolphins, but also important fishing grounds for artisanal fisheries. No studies have been carried out here to investigate the overlap and interactions between the fishing grounds and dolphin habitat. The present study aims to assess the potential occurrence of interactions between artisanal fisheries and bottlenose dolphins in these waters. Face to face interviews were conducted to investigate for the first time artisanal fishermen's perceptions of their interactions with bottlenose dolphins. A total of 131 fishermen (40.1% of the artisanal fleet for the Valencia region) participated of research. Among the interviewed fishermen, 86.1% perceived that dolphins damaged fishing gear as they attempted to feed, and they also detected significant direct damage to fish. Of all fishermen reporting a negative interaction with bottlenose dolphins, 76.3% also reported financial loss (2907.1 ± 2512.7 €/year (100–12,000). Despite the high level of interaction with dolphins reported, fishermen do not consider bycatch to be an important threat for bottlenose dolphins. Our results show geographical differences in fishermen's perceptions of damage caused by dolphins: while dolphins were considered to be the second cause of economic loss in the southernmost ports, fishermen from the northern ports considered interaction with bottom trawl boats to be more harmful than interaction with dolphins. The more intense interaction reported by fishermen in fishing ports in the southern study area may be associated with higher presence of bottlenose dolphin in these zones. Our study provides a useful insight into fishermen's perceptions of interaction between bottlenose dolphins and artisanal fisheries in this key area for the species in the western Mediterranean Sea. It also highlights the need for future work including direct observations of interactions and damage to gather reliable data to assess the need for conservation measures.

Whale lice (Cyamidae) are ectoparasitic amphipods exclusive to cetaceans. Data on their epidemiology usually come from species infecting baleen whales, which are large, slow-moving hosts. In this study, we provide data on infection parameters, population structure and microhabitat selection in a whale louse exclusive to delphinids, Syncyamus aequus, with the aim of comparing them with those from cyamid species from large whales. A total of 176 striped dolphins Stenella coeruleoalba stranded along the Mediterranean coast of Spain during 1980–2016 were examined. The prevalence of S. aequus was 27.3% (95% CI: 20.9–34.3), and populations were sparse, with a mean number of whale lice per infected host of just 4.5 (3.4–6.7). The parasites were found on the head, with a clearly nested pattern, with the blowhole being the most frequently occupied site, followed by the mouth corner and eyes. Single-male or single-female populations were found on as much as 39.6% of infected dolphins. The sex ratio did not significantly depart from 1:1. Females were significantly larger than males and exhibited low fecundity (

Pollution by marine litter is raising major concerns due to its potential impact on marine biodiversity and, above all, on endangered mega-fauna species, such as cetaceans and sea turtles. The density and distribution of marine litter and mega-fauna have been traditionally monitored through observer-based methods, yet the advent of new technologies has introduced aerial photography as an alternative monitoring method. However, to integrate results produced by different monitoring techniques and consider the photographic method a viable alternative, this ‘new’ methodology must be validated. This study aims to compare observations obtained from the concurrent application of observer-based and photographic methods during aerial surveys. To do so, a Partenavia P-68 aircraft equipped with an RGB sensor was used to monitor the waters off the Spanish Mediterranean coast along 12 transects (941 km). Over 10000 images were collected and checked manually by a photo-interpreter to detect potential targets, which were classified as floating marine macro-litter, mega-fauna and seabirds. The two methods allowed the detection of items from the three categories and proved equally effective for the detection of cetaceans, sea turtles and large fish on the sea surface. However, the photographic method was more effective for floating litter detection and the observer-based method was more effective for seabird detection. These results provide the first validation of the use of aerial photography to monitor floating litter and mega-fauna over the marine surface., This study was supported by the project MEDSEALITTER (1MED15_3.2_M12_334; European Union-European Regional Development Fund- Interreg MED). OGG’s Ph.D. was funded through an FPU scholarship granted by the Spanish Government.

The following protocol is intended to respond to the requirements set by the European Union’s Marine Strategy Framework Directives (MSFD) for the D10C3 Criteria reported in the Commission Decision (EU), related to the amount of litter ingested by marine animals. Standardized methodologies for extracting litter items ingested from dead sea turtles along with guidelines on data analysis are provided. The protocol starts with the collection of dead sea turtles and classification of samples according to the decomposition status. Turtle necropsy must be performed in authorized centers and the protocol described here explains the best procedure for gastrointestinal (GI) tract isolation. The three parts of the GI (esophagus, stomach, intestine) should be separated, opened lengthways and contents filtered using a 1 mm mesh sieve. The article describes the classification and quantification of ingested litter, classifying GI contents into seven different categories of marine litter and two categories of natural remains. The quantity of ingested litter should be reported as total dry mass (weight in grams, with two decimal places) and abundance (number of items). The protocol proposes two possible scenarios to achieve the Good Environmental Status (GES). First: “There should be less than X% of sea turtles having Y g or more plastic in the GI in samples of 50-100 dead turtles from each sub-region”, where Y is the average weight of plastic ingested and X% is the percentage of sea turtles with more weight (in grams) of plastic than Y. The second one, which considers the food remain versus plastic as a proxy of individual health, is: “There should be less than X% of sea turtles having more weight of plastic (in grams) than food remains in the GI in samples of 50-100 dead turtles from each sub-region”. © 2019 Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

A juvenile male loggerhead sea turtle (Caretta caretta) was found dead in April 2015, entangled in a trammel net on the Mediterranean coast of Spain. Post-mortem examination revealed the presence of ninety-five isopods dispersed in the coelomic cavity, and inside the oesophagus and skull. All individuals found scavenging on the sea turtle were identified as Natatolana neglecta (Hansen, 1890) (Isopoda: Cirolanidae). Genetic analysis of the isopod gut contents showed that they were feeding on turtle tissue, confirming that N. neglecta can also attack dead sea turtles. This study shows the value of cirolanids as potential indicators of the cause of death in stranded sea turtles.

[EN] Several loggerhead sea turtle (Caretta caretta) nesting events have been recorded along Spain's Mediterranean coast, outside its known nesting range, in recent years. In view of the possible expansion of its nesting range and considering the conservation status of this species, management measures like nest protection and head-start programs have been implemented. To study the dispersal behavior and survival of head-started loggerheads, 19 post-hatchlings from three nesting events were satellite tracked after their release in three consecutive years (2015-2017). This paper presents the first study of survival probabilities and dispersal movements of loggerhead post-hatchlings in the Mediterranean basin. Monitored post-hatchlings dispersed over large areas using variable routes, mainly off the continental shelf. Nonetheless, post-hatchlings dispersed to high-productivity warmer areas during the coldest months of monitoring. These areas might be optimum for their survival and development. We observed differences regarding dispersal orientation and routes among individuals, even from the same nest, release date, and location. Our survival models contributed to improving current survival estimates for sea turtle post-hatchlings. We observed a high probability of survival in head-started individuals during the first months after release, usually the most critical period after reintroduction. The data did not support an effect of habitat (neritic or oceanic) in survival, or an effect of the region (Balearic sea or Alboran sea) in survival probability. Differences in survival between nests were observed. These differences might be related to parasitic infections suffered during the head-starting period. This study shows that nest management measures may contribute to the conservation and range expansion of the loggerhead turtle population in the western Mediterranean., This satellite study was funded by Universitat Politecnica de Valencia, Ministerio de Agricultura y Medio Ambiente (ref: 16MNSV006), Ministerio de Economia, Industria y Competitividad (ref: CGL2011-30413), Fundacion CRAM, Fundacion Hombre y Territorio and Eduardo J. Belda. Corresponding author, S. Abalo, was supported by a Ph.D. grant (FPU) from Ministerio de Educacion, Cultura y Deporte (Spain). J. Tomas is also supported by project Prometeo II (2015) of Generalitat Valenciana and project INDICIT of the European Commission, Environment Directorate-General. We are extremely thankful to the entities that have collaborated: we thank all professionals at the Oceanografic, especially at the ARCA Rehabilitation Center, for their many efforts and whole-hearted dedication to the best animal care. In particular, we are grateful to the Conselleria d'Agricultura, Medi Ambient, Canvi Climatic i Desenvolupament Rural of the Valencia Community Regional Government. We also thank the professionals at Centro de Recuperacion de Animales Marinos (CRAM) for their dedication and animal care. We are thankful to the Marine Zoology Unit of the University of Valencia, NGO Xaloc, EQUINAC, Aquarium of Sevilla, Donana Biological Station (EBD-CSIC) and to involved professionals at Consejeria de Medio Ambiente y Ordenacion del Territorio (CMAOT) of Junta de Andalucia, especially at the Andalusian Marine Environment Management Center (CEGMA) for their efforts with animal care, logistics for release events and necropsy of "Rabiosa". We are particularly grateful to the people who called 112 to report a nesting event and to the nest custody volunteers. Thanks are due to the staff of Parador de El Saler for volunteering logistical support. The authors wish to acknowledge the use of the Maptool program for analysis and graphics in this paper. Maptool is a product of SEATURTLE.ORG (Information is available at www.seaturtle.org). Also, we acknowledge the use of the Douglas Argos Filter (DAF) utility in Movebank (www.movebank.org) and especially David Douglas for his help and recommendations. Finally, we thank the reviewers for their reviewing efforts.

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 (

The beaches of Jaragua National Park in the Dominican Republic are the country's last known major nesting site for the leatherback marine turtle Dermochelys coriacea. This nesting aggregation is threatened by widespread illegal egg take, and clutch relocation and artificial incubation have been carried out as protection measures since 1974. We assess the efficacy of such efforts and investigate how artificial incubation may be influencing the success and sex ratios of clutches. We compare hatching success, incubation duration and embryo mortality in in-situ clutches (n = 43) with those incubated artificially at sites in the east and west of the Park (n = 35 and n = 31, respectively). Our results show that in the west, artificial incubation significantly decreases hatching success in clutches. In the east the duration of incubation is increased, which we predict would result in an increase in the number of males from these clutches. Clutch relocation is currently the only viable conservation option for clutches on eastern beaches because of illegal egg take but action is needed to ensure that the natural sex ratio is not distorted. However, on the western beaches in situ clutch incubation seems possible through beach protection. Further community engagement and enforcement are required to improve conservation measures at eastern beaches if long-term, less sustainable intervention is to be avoided.

A questionnaire-based survey of fishermen was conducted in the Valencia region (eastern Spain) to assess the levels of marine turtle bycatch. Interviews covered 41.3% of the bottom trawling fleet in the region and included 111 fishermen (one per boat). Results were combined with those from previous studies conducted in neighbouring regions using the same methodology to assess the global impact of bottom trawling on the western Mediterranean stock of the loggerhead turtle (Caretta caretta). Estimated turtle catch per unit effort (CPUE) is 0.09 turtles per vessel per month, according to the information reported by fishermen. As a consequence, the whole fleet of bottom trawlers operating off the Valencia region was involved annually in 238 turtle bycatch events (95%, CI: 173–304). Ivlev's electivity index revealed that bottom trawling bycatch was higher than expected according to fishing effort in the northern part of the study area, where the continental shelf widens. The fishermen's perception was that the local stock of loggerhead turtles is declining, and that drifting longlines and bottom trawling are, at least in part, responsible for this trend. According to previous studies as well as the current results, bottom trawlers operating off mainland Spain capture mainly loggerhead turtles from the rookeries in the eastern Mediterranean, with only a low percentage of turtles of Atlantic origin. Loggerhead turtle bycatch by bottom trawling deserves more attention in the Valencia region, particularly in its northern part. Conservation measures in the area are discussed. Copyright © 2014 John Wiley & Sons, Ltd.

Protected areas are considered essential elements for global biodiversity conservation. They may not necessarily result in an effective conservation of resources in developing countries due to lack of funding for management and enforcement. In addition, poor governance aligned with conflicts of economic interests related to their use can further threaten their integrity and persistence. In the Dominican Republic, the western beaches of the Jaragua National Park (JNP), a protected area which is also part of a UNESCO Biosphere Reserve, have been proposed for development using a mass-tourism model. One of the most charismatic species found in this area is the leatherback turtle (Dermochelys coriacea). In the present study, we assess hatching success, and factors affecting it, to determine the reproductive value across the area for the leatherback turtle. The main factors found driving hatching success at the study beaches are beach sector, incubation duration, date of lay and clutch size. Our results show that clutches in La Cueva (located in the buffer zone of the park) and Bahia de las Aguilas (located inside the limits of the park) have an unusually high hatching success (~75 %) for this species, highlighting the importance of increasing protection efforts at these sites. We strongly recommend including La Cueva inside the limits of the JNP.

Saona Island hosts the last hawksbill turtle (Eretmochelys imbricata) nesting population in the Dominican Republic, which has experienced a severe decline in the last decades, mostly due to illegal egg take. Here we present the results of an artificial incubation programme started in 2007 to protect the clutches from human predation. A preliminary survey in 2006 showed that about 60% of clutches laid were taken by humans. Over the study period (2007–2010) we recorded 400 clutches, of which 38.2% were predated by humans, 40.7% were artificially incubated and 21% were incubated in situ. Overall, the artificial incubation programme allowed the release of 12,340 hatchlings. No differences were found in hatching and emergence success between clutches incubated in situ and clutches artificially incubated. However, incubation temperatures and incubation durations recorded suggest a male-biased hatchling sex-ratio in artificially incubated clutches. Although artificial incubation may mitigate the effect of egg take, our results indicate that other measures, such as clutch relocation to protected sections of the beach should be taken. Beach patrolling and education are currently implemented so that artificial incubation will be eventually phased out in favour of in situ incubation.

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.

Nesting by marine turtles in the Caribbean has declined considerably, mainly because of human exploitation, but there has previously been no monitoring in the Dominican Republic. We present the first detailed assessment of the status of marine turtle nesting in the country, based on surveys during 2006–2010. Nesting populations of hawksbill Eretmochelys imbricata and leatherback turtle Dermochelys coriacea are of regional importance and the green turtle Chelonia mydas is still present, although nesting in low numbers. The two main nesting sites are within protected areas: the Jaragua National Park in the south-west, important for leatherback turtles (mean of 126 nests per season), and Del Este National Park on Saona Island in the south-east, principally for hawksbill turtles (mean of 100 nests per season). Comparison with historical data suggests all rookeries are profoundly reduced in size. Although the main nesting beaches are within protected areas, illegal egg-take and meat consumption continues there, and also elsewhere in the country.

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.

We report the first confirmed occurrence of a Lepidochelys olivacea in the Mediterranean Sea based on the study of an individual stranded on a beach, located in the town of Oropesa del Mar (40º05ʹ32ʺN, 0º08ʹ02ʺE), Castellón province, East Spain, in May 2014. Morphological and genetic analyses were used to confirm the identification of the species. The individual had a sequence that matched the 470 bp Lepidochelys olivacea haplotype F (Genbank accession number: AF051773), found in several Atlantic populations. This becomes one of the northernmost known occurrences of olive ridleys in the world and is the first reports of this species in the Mediterranean Sea.