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Up to date 264 Marine Protected Areas (MPAs) have been declared in the western Mediterranean Sea. The management plans of 25 of these MPAs include the loggerhead sea turtle (Caretta caretta) as a priority species to protect. However, the actual use of these MPAs by the species remains unknown. Therefore, it is important to assess their contribution to loggerhead conservation in the area. To this end, satellite tracking data of 103 loggerhead turtles of varying sizes and life stages released in Spanish Mediterranean waters and Southern Tyrrhenian Sea over the 2003–2018 period were herein used. Home range and use of MPAs by tracked loggerhead turtles were analysed using post-processed state-space model locations. The tracked turtles visited several Mediterranean MPAs, but barely used them (mean percentage of monitoring time=12.6 ± 18.2 %). There was very little overlap between turtle’s core areas and tracks with the protected areas. Indeed, most of the core areas and high-density areas estimated (>85 %) were not included within any of the MPAs. Furthermore, less than 5 % of the Mediterranean MPAs were used by any tracked loggerhead sea turtles. Most of these MPAs have no protection measures that focus on this species. Loggerheads mainly use wide oceanic zones and international waters, which are difficult to protect. A high-use core area was identified for loggerhead turtles, located at the western waters of the Algerian Basin, an important fishing area outside any designated MPA and with no protection measures that focus on marine turtle conservation. We conclude that existing MPAs in the western Mediterranean may not contribute enough to loggerhead turtle conservation. We propose potential MPAs designations to be considered for loggerhead sea turtle conservation in the Mediterranean Sea at the Alboran Sea, the Algerian basin, the Northern area of the Strait of Sicily, Northeast Tunisian waters, waters around Malta, waters at the Tyrrhenian Sea and at the Ionian Sea.

Global warming is affecting habitat quality and availability on our planet and some species are predicted or are by now changing their distribution range. Here we show that loggerhead turtles have already started to expand their nesting range into the Western Mediterranean, which has until recently hosted only sporadic nests. We compiled information on nesting activity from beaches surrounding the Western Mediterranean and collected metadata on loggerhead turtle nests in Spain, France, Italy, and Tunisia between 2010 and 2020 to provide an exhaustive overview on the phenomenon of emerging new nest sites for loggerhead turtles. The number of recorded nests has increased drastically since 2013 from 1 to 3 nests/year to a record number of 84 registered in 2020. While this increase may partly be explained by grown awareness and reporting by citizens, there is no doubt of an upward trend in nesting activity. The nests are unevenly distributed over the study area with most nests occurring on the coasts of the warmer Tyrrhenian Sea. A hotspot analysis identified beaches in SW Italy, SE Sardinia, and NW Tunisia with statistically significant clustering of nests. Within these hotspots, three beaches in SW Italy and one in Tunisia had nests at least four out of the five last years. Nesting phenology corresponds to that of Eastern Mediterranean rookeries, and mean hatching success of naturally incubating, non-manipulated nests was 66 %, although there was variability across the region. Mean incubation durations also varied between countries indicating a diversity in inferred sex ratios, with sufficient female production to foster future colonisation of this region. Unfortunately, these beaches are already under high tourist pressure and subject to intense coastal development, imposing many threats to the females, eggs, and hatchlings. Thus, while this study reveals the unique opportunity to witness and study an ongoing new colonisation process in loggerhead turtles, it also calls for urgent proactive conservation actions to mitigate these threats and allow the turtles to establish new rookeries.

We provide the raw data of 44 satellite-tracked loggerhead sea turtles from different life-stages collected between 2016 and 2018. Depending on life-stage and tag availability a different satellite tag was attached to the loggerhead carapace. Location data were collected using the Argos system. We made publically available for the first time in the Mediterranean: (i) the satellite-tracking data for 17 one-year-aged post-hatchlings of loggerhead sea turtle came from two nests laid on the Mediterranean Spanish coast; (ii) the satellite-tracking data for 4 loggerhead nesting females collected from nesting events occurred on the Spanish Mediterranean coast. Besides, another 23 juvenile and adult loggerhead sea turtles were monitored and their data were made also available. Our dataset provide the turtle identity name or number, the date and coordinates of the location data, and the Argos location class associated. Our data contribute to the knowledge about the spatial use of the loggerhead sea turtle in the Mediterranean Sea and could be used in further analysis regarding habitat use and dispersal of this species in the Mediterranean Sea. Specially, nesting females and post-hatchlings data contribute to shed light about these life-stages related to nesting events out of the usual nesting range in the western Mediterranean, for which data still remains scarce. Also, data could be compared to further similar research in satellite-tracking loggerhead sea turtles in the Mediterranean basin.

The Cetacean Migration Corridor is an important marine protected area for cetacean species in the Western Mediterranean, and part of its waters constitute the main fishing grounds for the Valencia region (East Spain) fishing fleet. Here we aim to assess the interactions between all active fisheries operating in the waters of the Valencia region and the cetacean species inhabiting this area. A total of 282 face-to-face interviews (51.37% of the total fleet) to fishers were held on 20 ports at the study area to gather information about cetacean by-catch and all types of interactions between fisheries and cetaceans. The interviewed bottom trawlers (n = 148 boats) reported a monthly by-catch rate (C) of 0.01 dolphins per vessel. Bottom trawling vessels operating at neritic zones only reported by-catch of common bottlenose dolphin (C = 0.009), while those fishing at oceanic zones by-caught striped dolphin (C = 0.006) and common bottlenose dolphin (C = 0.003). The interviewed artisanal fishers (n = 114 boats), the second most important fishery in the study area, only reported one dolphin by-catch event, but 90 of these boats communicated continued negative interactions with the common bottlenose dolphin, causing gear damage and catch take. The interviewed vessels gave an estimation of their annual economic loss produced by this interaction (mean ± SD: 2,998.10 ± 2095.02 € per boat). Other fisheries operating in the Valencia region were purse-seiners (n = 15 boats) and pelagic longlines, a fishery that has almost disappeared in the study area (n = 5 boats). The first one had the highest estimated dolphin by-catch rate (C= 0.04) and mainly interacted with common bottlenose dolphin, but also with striped dolphin. The information gathered from interviews was complimented with long-term stranding data (1990–2020). Despite the fact that only 7.80% of all recorded stranded cetaceans showed fisheries interaction signs, 26.72% of the common bottlenose dolphins recorded showed evidence of this interaction, thus confirming that it is the cetacean species most affected by fisheries in the area. Records of stranded striped dolphin (6.45%) also showed evidence of fisheries interaction. Based on both dolphin by-catch and gear damage, management plans are needed in the area to ensure cetacean conservation and also fisheries sustainability in waters inside and around marine protected areas at the Spain’s Mediterranean.

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.