The colonisation of new suitable habitats is crucial for species survival at evolutionary scale under changing environmental conditions. However, colonisation potential may be limited by philopatry that facilitates exploiting successful habitats across generations. We examine the mechanisms of long distance dispersal of the philopatric loggerhead sea turtle (Caretta caretta) by analysing 40 sporadic nesting events in the western Mediterranean. The analysis of a fragment of the mitochondrial DNA and 7 microsatellites of 121 samples from 18 of these nesting events revealed that these nests were colonising events associated with juveniles from distant populations feeding in nearby foraging grounds. Considering the temperature-dependent sex determination of the species, we simulated the effect of the incubation temperature and propagule pressure on a potential colonisation scenario. Our results indicated that colonisation will succeed if warm temperature conditions, already existing in some of the beaches in the area, extend to the whole western Mediterranean. We hypothesize that the sporadic nesting events in developmental foraging grounds may be a mechanism to overcome philopatry limitations thus increasing the dispersal capabilities of the species and the adaptability to changing environments. Sporadic nesting in the western Mediterranean can be viewed as potential new populations in a scenario of rising temperatures.

Twenty live and five dead juvenile and subadult loggerhead sea turtles were examined ultrasonographically. Ten soft tissue areas of the integument were used as acoustic windows: cervical-dorsal and cervical-ventral, left and right cervicobrachial, left and right axillary, left and right prefemoral and left and right postfemoral windows. Anatomical cross-sections were performed on the dead turtles to provide reference data. The fourth and fifth cervical vertebrae, the spinal cord, and the venous sinuses of the external jugular vein were clearly visible through the cervical-dorsal acoustic window, and the oesophagus and the heart were imaged through the cervical-ventral acoustic window. The stomach was more frequently visible through the left axillary acoustic window. The liver could be imaged through both sides, but the right axillary acoustic window was better for visualising the gall bladder. The large and small intestines and the kidneys were visible through the right and left prefemoral acoustic windows; the kidneys were easily identified by their intense vasculature.

The integrated study of ocean health and human health is an emerging area of increasing global importance. Growing evidences demonstrate that the health of the ocean and the health of humans have always been and will continue to be, inextricably linked. Our actions toward the oceans will significantly influence the future of the whole planet and, in turn, our own health. The current review of these issues arose from a summer school in San Sebastian (Spain), from 5th to 7th June, 2019. An interdisciplinary group of researchers discussed key risks (e.g., microbial pollution, pharmaceuticals, harmful algal blooms, plastic pollution) and benefits (e.g., bathing waters, recreation, tourism) of the seas and global ocean for humanity; and debated the future priorities and potential actions for a joint Oceans and Human Health research and governance programme in Europe. The aim of this review is to contribute to the emerging scientific agenda on ocean health and human health, as well as coordinate efforts with stakeholders, policy makers and the general public. This agenda operates within the larger context of the upcoming United Nations Decade of Ocean Science for Sustainable Development: 2021-2030, which strives to achieve the Sustainable Development Goals (SDG), including healthy (human) lives and well-being (SDG3) and conserving and sustainably using the oceans (SDG14), among others. In addition to summarizing some of the key risks and benefits, therefore, we describe the governance of oceans and health interactions (especially in Europe), and we finish by proposing a list of elements for potential future research priorities on oceans and human health.

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Decompression sickness (DCS) was first diagnosed in marine turtles in 2014. After capture in net fisheries, animals typically start showing clinical evidence of DCS hours after being hauled on-board, often dying if untreated. these turtles are normally immediately released without any understanding of subsequent clinical problems or outcome. The objectives of this study were to describe early occurrence and severity of gaseous embolism (GE) and DCS in marine turtles after incidental capture in trawl gear, and to provide estimates of on-board and post-release mortality. Twenty-eight marine turtles were examined on-board fishing vessels. All 20 turtles assessed by ultrasound and/or post-mortem examination developed GE, independent of season, depth and duration of trawl and ascent speed. Gas emboli were obvious by ultrasound within 15 minutes after surfacing and worsened over the course of 2 hours. Blood data were consistent with extreme lactic acidosis, reduced glomerular filtration, and stress. Twelve of 28 (43%) animals died on-board, and 3 of 15 (20%) active turtles released with satellite tags died within 6 days. This is the first empirically-based estimate of on-board and post-release mortality of bycaught marine turtles that has until now been unaccounted for in trawl fisheries not equipped with turtle excluder devices.