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Sea turtles are globally threatened due to short- and long-term exposure to anthropogenic activities. Many life-history traits make it difficult to study these species in the wild. Stranding events provide invaluable data to infer key aspects of sea turtle ecology, such as regional occurrence, health status, mortality rates, and potential threats. In this study, we investigate spatial and temporal patterns of sea turtle occurrence and mortality in the southwestern Atlantic Ocean based on a systematic, large-scale survey programme covering 1040 km of coastline during 732 d of two consecutive years. From the 12 571 animals recovered, juvenile green turtles were the most common (90.4%), but four other species were also recorded. A significant non-linear effect of time and space in the number of stranding events was observed. The most parsimonious mixed linear model further indicated that stranding events were influenced by individual (sex, size), health (body condition, pathologies, decomposition), and oceanographic factors (chlorophyll-a, sea surface temperature, salinity, wave height). More than simply describing the spatiotemporal occurrence and aspects of sea turtles' life history in an otherwise understudied area, this intensive field study provides evidence for relatively high mortality rates—an essential baseline information for guiding conservation efforts. [ABSTRACT FROM AUTHOR]

Incidental capture by fisheries is one of the principal threats to sea turtles. This study analysed spatial and temporal patterns of sea turtle bycatch, and estimated the direct initial mortality rate of these animals, in the industrial double‐rig‐bottom trawl fishery in south‐eastern Brazil. This is also the first attempt to relate bycatch/at‐sea mortality in bottom trawling to stranded turtles found along the adjacent coast.The fishery was monitored from October 2015 to April 2018 through data collected voluntarily by the captains of eight industrial double‐rig trawlers. Two hundred and one sea turtles were captured during 9362 tows (43,657.52 trawling hours), resulting in a catch per unit effort (CPUE) of 0.0025 ± 0.0032 turtles h−1 with a standard net of 30.5 m headrope, with no significant difference between the estimated CPUEs for licensed shrimp and demersal fish trawlers.Caretta caretta (52.24%) and Lepidochelys olivacea (38.81%) were the most frequently captured species. According to Generalized Linear Models, C. caretta bycatch was significantly higher during winter, at lower latitudes (−24° to −23°) and higher longitudes (−42° to −40°), while the L. olivacea bycatch was significantly higher at higher latitudes (−23° to −21°). The direct initial mortality rate of sea turtles in the shrimp trawlers was 7.65 ± 3.85%. However, none of the dead individuals subsequently released with plastic tags (n = 10) were found stranded on the coast. Mortality was not significantly related to the depth or duration of the trawling.The results of this study suggest the need for improvements to the current management of the bottom trawl fishery in Brazil, moving from a species‐based to a spatial and seasonal‐based approach. There is also a need to develop turtle excluder devices adapted to local fishing conditions. [ABSTRACT FROM AUTHOR]

Fisheries are recognised as a major threat to sea turtles worldwide. Oceanic driftnets are considered the main cause of the steep decline in Pacific Ocean populations of the leatherback sea turtle Dermochelys coriacea. The world's largest leatherback population nests in West Africa and migrates across the Atlantic Ocean to feed off the South American coast. There, the turtles encounter a range of fisheries, including the Brazilian driftnet fishery targeting hammerhead sharks. From 2002 to 2008, 351 sea turtles were incidentally caught in 41 fishing trips and 371 sets. Leatherbacks accounted for 77.3% of the take ( n = 252 turtles, capture rate = 0.1405 turtles/km of net), followed by loggerheads Caretta caretta (47 individuals, capture rate = 0.0262 turtles/km of net), green turtles Chelonia mydas (27 individuals, capture rate = 0.0151 turtles/km of net) and unidentified hard-shelled turtles (25 individual, capture rate = 0.0139 turtles/km of net) that fell off the net during hauling. Immediate mortality (i.e., turtles that were dead upon reaching the vessel, excluding post-release mortality) was similar among the species and accounted for 22.2 to 29.4% of turtles hauled onboard. The annual catch by this fishery ranged from 1,212 to 6,160 leatherback turtles, as estimated based on bootstrap procedures under different fishing effort scenarios in the 1990s. The present inertia in law and enforcement regarding gillnet regulations in Brazil could result in the reestablishment of the driftnet fishery, driving rates of leatherback mortality to levels similar to those observed in previous decades. This development could potentially lead to the collapse of the South Atlantic leatherback population, mirroring the decline of the species in the Pacific. In light of these potential impacts and similar threats to other pelagic mega fauna, we recommend banning this type of fishery in the region. [ABSTRACT FROM AUTHOR]

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Copyright of Arquipélago. Life & Marine Sciences / Ciencias Biológicas e Marinhas is the property of Universidade dos Acores and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Studying how host characteristics and ecology affect the mating systems of symbiotic crustaceans offers an opportunity to understand how ecological factors contribute to the evolution of different animal mating systems. In theory, symbiotic crustaceans should display social monogamy with long-term heterosexual pairing when hosts are relatively small in body size and structurally simple, and when hosts have relatively low abundance in habitats where the risk of mortality for symbionts (e.g., predation) away from hosts is high. We test this prediction in the mating system of the flotsam crab ( Planes major ) and its facultative association with loggerhead sea turtles ( Caretta caretta ). First, we found that the overall population and sex distributions were non-random and crabs inhabited host turtles as heterosexual pairs more frequently than expected by chance, which supports the hypothesis that P . major is socially monogamous on C . caretta . Second, we found that male crabs pair with females regardless of their reproductive state, male–female pairs do not display size-assortative pairing, crab body size and host turtle body size are not correlated, and crabs display reverse sexual dimorphism in body size and conventional sexual dimorphism in weaponry. These results do not support the hypothesis that social monogamy in P . major is always long term. Instead, our results suggest that the duration of social monogamy in P . major is likely variable and may involve some degree of host switching and intra-sexual (mostly male–male) competition. Our results were only partially consistent with theoretical considerations for how host characteristics and ecology affect the mating systems of symbiotic crustaceans, and future studies should focus on quantifying the degree and direction of host switching to better understand the factors that affect the duration of monogamous pairing when P . major associates with C . caretta . [ABSTRACT FROM AUTHOR]

Abstract: The decline of populations of certain seabirds and sea turtles around the world is partly related to their incidental capture in large-scale fisheries. However, the impacts of small-scale fisheries on endangered seabirds and sea turtles, being carried out in many places around the world, have been largely neglected by scientists and governments. We monitored 178 fishing days and described a range of poorly known hook-and-line commercial fisheries carried out by the Itaipava fleet, southeastern Brazil, composed by 497 vessels and deploying hooks from 18°S to 35°S. Seven fisheries were defined: fast trolling for tuna and tuna-like species, slow trolling for Bigeye tuna, handlining, surface longline for Dolphinfish, pelagic longline for Swordfish, bottom dropline, and pole-and-line with live bait. We observed bycatch of 47 seabirds of six species and 45 turtles of four species. Capture rates were higher for the surface longline for Dolphinfish (0.15 birds/1000 hooks and 1.08 turtles/1000 hooks), slow trolling for Bigeye tuna (0.41 birds/day) and handlining targeting Yellowfin tuna (0.61 birds/day). Endangered Spectacled petrel (Procellaria conspicillata), Atlantic Yellow-nosed (Thalassarche chlororhynchos), and Black-browed (T. melanophris) albatrosses were the main seabirds caught. Immature Loggerhead turtles (Caretta caretta) and immature or adult Leatherback turtles (Dermochelys coriacea) were the main sea turtles affected by the surface longline for Dolphinfish. Monitoring the fleet and bycatch levels, development of mitigation measures, establishment of educational programs, government control over the fleet, and enforcement, are urgently required for the hook-and-line fisheries described in the present study. [Copyright &y& Elsevier]

Green sea turtles (Chelonia mydas) switch habitats during their development, moving from pelagic to neritic areas and then commuting between nesting and foraging grounds during adulthood. Due to their predominantly coastal habitats, they are under a range of anthropogenic threats. We monitored turtles incidentally captured in fishing weirs in Ceará state, northeastern Brazil, over a decade and provided an overview of capture rates in the fishery during previous decades. Between 2008 and 2018, 2335 captures were recorded, 76% were only once. Most recaptures (86%) occurred up to six months after the first capture, with a mean growth rate of 6.7 ± 3.6 cm year−1. Capture rates varied between years, with the highest rates during the historical period, peaking in 1962 (0.16 turtles day weir−1). Between 2008 and 2018, the daily capture rate was 0.07 turtles day weir−1. Similar to other areas, the use of turtles as a fishery resource seems to have reduced population sizes in the Atlantic Ocean. On the other hand, the intensive monitoring of local weirs provided an opportunity to mobilize the community regarding their conservation, which in turn could have supported the recovery of turtles from a number of distant colonies. The relatively constant and year-round capture of green sea turtles reflects the presence of individuals from different rookeries and demonstrates the importance of the region as a developmental ground for juveniles from different nesting areas, with high growth rates compared with other feeding areas. Partnership with local fishermen and the long-term monitoring of passive nonlethal fishing weirs are key tools in supporting sea turtle conservation. • Interdecadal overview of sea turtle captures show influence of conservation actions. • Fishermen behavior towards sea turtle meat consumption changed. • Fishing weirs over 5 m depth capture turtles with curved carapace length >50 cm. • Most recaptures occurred within six months, suggesting regional residence. • In the tropical area, green sea turtles had higher growth rates than elsewhere. [ABSTRACT FROM AUTHOR]