The impact of macroplastic debris (>5 mm) on marine life is a global concern but has rarely been investigated in Thailand. This study investigated the relationship between stranded sea turtles and ...macroplastics in the Central Gulf of Thailand. Records of stranded turtles (n = 388) from 2017-2020 were analysed retrospectively to determine their interaction with macroplastics. In addition, macroplastics collected from the gastrointestinal (GI) tracts of 30 dead stranded turtles and 13 beaches (along a 100 m transect mid-way between high and low tide) between 2019 and 2020 were investigated. Types and composition of macroplastics were identified with the use of a stereomicroscope and Fourier-transform infrared spectrometer. Green turtles
Chelonia mydas
comprised the majority of stranded turtles (74%, n = 251), and macroplastics (entanglement or ingestion) were the leading cause of death (n = 152). Most stranded turtles were juveniles (65%), and their stranding was significantly correlated with macroplastics (p < 0.001). Juveniles were more prone than adults to become entangled (p = 0.007), while adults had a higher ingestion rate than juveniles (p = 0.009). Plastic fibres were commonly found in the GI tracts (62%, n = 152 of 244) and beaches (64%, n = 74 of 115). Most fibres from the GI tracts (83%, n = 126 of 152) and beaches (93%, n = 68 of 74) were fishing nets made of polyethylene or polypropylene. We conclude that fishing nets are a significant cause of sea turtle stranding in the Central Gulf of Thailand, and this issue requires immediate resolution.
Conservation monitoring of highly mobile species in relatively inaccessible habitats presents a considerable challenge to wildlife biologists. Effective conservation strategies require knowledge of ...cetacean ecology that is often challenging and expensive to obtain. Despite their caveats, stranding data represent an underused resource to study the long-term dynamics of cetacean populations. Using long-finned pilot whale (LFPW;
Globicephala melas edwardii
) strandings on the New Zealand coast as a case study, we present a novel approach to demonstrate how stranding data can inform conservation management of data-poor species. A total of 8571 LFPWs stranded on the New Zealand coast within a 40-year period between January 1978 and December 2017. Overall, where sex was recorded, mass stranded adults were significantly biased towards females, while a significant male bias was observed in juveniles. Strandings occurred in all months, though significant seasonal variation was evident, with 66% of stranding events reported during austral spring and summer months (October–February). Hot spot analysis (ArcGIS) identified the majority of LFPWs stranded at Golden Bay, Great Barrier Island, Stewart Island and the Chatham Islands, with emerging hot spot analysis (ArcGIS) used to identify spatiotemporal trends. While emerging hot spot analysis revealed no significant temporal trend in the annual frequency of stranding events or numbers of individuals stranded, it did reveal a significant spatiotemporal trend, with the numbers of stranded individuals declining in areas of the Far North, Coromandel, Canterbury, Otago and the Chatham Islands, and increasing in Golden Bay and Stewart Island. When combined with other contextual information, such trends help identify the most significant clusters of LFPW strandings on the New Zealand coast, provide baseline ecological data on a poorly understood subspecies, and can be used to guide conservation management of
G. m. edwardii
in New Zealand waters.
Cetacean morbillivirus (CeMV) causes illness and death in cetaceans worldwide; the CeMV strains circulating in the Southern Hemisphere are poorly known. We detected a pilot whale CeMV strain in 3 ...short-finned pilot whales (Globicephala macrorhynchus) stranded in Brazil during July-October 2020. Our results confirm this virus circulates in this species.
Using Irish strandings data collected between 2002 and 2014, seasonal and annual trends in the number of strandings for all strandings identified to species level (N = 1480), and for the five most ...frequently reported species: common dolphin (25.7% of records), harbour porpoise (22.2%), long-finned pilot whale (8.8%), striped dolphin (6.9%) and bottlenose dolphin (6.9%) were investigated. With the exception of bottlenose dolphins, there was a significant linear increase in the number of strandings across years for all species and for all strandings collectively, that were identified to species-level. Only common dolphins demonstrated a significant increase in the proportion of records relative to all other strandings, which may be indicative of a real rise in the number of strandings of this species. Common dolphins and harbour porpoises showed a similar significant difference in monthly strandings, with more strandings occurring during the earlier months of the year. Significant differences in the gender of stranded animals were found in common, striped, bottlenose and Atlantic white-sided dolphins and sperm and pygmy sperm whales. Live and mass stranding events were primarily comprised of pelagic species. Most strandings occurred on the south and west coasts, with two hotspots for live and mass strandings identified. The patterns and trends identified are discussed in relation to the caveats in interpreting strandings data. Specifically to Ireland, the findings highlight the urgent need to build on the current volunteer reporting network and augment this comprehensive dataset with post-mortem examinations to better understand the cause of the trends identified. The importance of strandings data in informing conservation and management guidelines of these species’ is discussed.
Stranded sea turtles provide valuable information about causes of mortality that threatens these imperiled species. Many potential factors determine whether drifting sea turtles are deposited on ...shore, discovered by people, and reported to stranding networks resulting in successful documentation. We deployed 182 sea turtle cadavers and 115 wooden effigy drifters with affixed GPS-satellite tags to study stranding probability in the northern Gulf of Mexico (nGOM) in an effort to better understand seasonal stranding variations in this region. Public reports of beached carcasses were recorded to determine reporting rates. Season and distance from shore greatly influenced beaching results. During winter months when strandings are infrequent and sea turtle abundance is likely low in cold nearshore waters, carcasses had an 80–90% probability of beaching. Beaching probability was reduced to 37–50% during the spring, which is the period of greatest strandings in this region. During summer months when relatively few strandings are documented, the probability of a carcass beaching dropped to only 4–8%. Low summer stranding rates were coincident with higher rates of decomposition (7%) attributed to warmer water temperatures, more frequent scavenging (69% of carcasses), and shifting wind and current patterns which drive carcasses offshore or to remote locations. As waters cooled in the fall, probability of carcasses beaching increased to 40–48%, coincident with a small pulse in strandings that often occurs during this period. Only 28% of carcasses and effigies came ashore on mainland beaches and were easily available for discovery by the public, 49% were on barrier islands that are publicly accessible and 23% beached in dense salt marshes where discovery would be unlikely. The 47% of objects that did not beach included those lost at sea and carcasses that were likely scavenged or decomposed. Only 22% of beached carcasses were reported due to infrequent (11%) reporting on barrier islands. Notably, only 50% of carcasses deposited on mainland beaches were reported, which was lower than anticipated. We recommend additional efforts to increase reporting rates of carcasses by the public and use of dedicated surveys to detect stranded sea turtles, especially on barrier islands in this region.
Plastic pollution is an omnipresent problem that threatens marine animals through ingestion and entanglement. Marine mammals are no exception to this rule but their interaction with plastic remains ...understudied in the Mediterranean Sea. Here we highlight this problem by analyzing the stomach contents of 34 individuals from seven odontocete species stranded in Greece. Macroplastic (>5 mm) was found in the stomachs of nine individuals from four species (harbour porpoise Phocoena phocoena, Risso's dolphin Grampus griseus, Cuvier's beaked whale Ziphius cavirostris and sperm whale Physeter macrocephalus) with the highest frequency of occurrence in sperm whales (60%). Gastric blockage from plastic was presumably lethal in three cases, with plastic bags being the most common finding (46%). Plastic ingestion is of particular conservation concern for the endangered Mediterranean sperm whales. A regular examination of stranded cetaceans with a standardised protocol is critical for allowing spatiotemporal comparisons within and across species.
•At least half the cetacean species regularly found in Greece ingest macroplastics.•60% of sperm whales in the Greek seas have macroplastics in their stomach.•Macroplastic ingestion by odontocetes can be often lethal due to gastric blockage.•A standardised approach is needed to evaluate the threat of plastic to cetaceans.
Fish can be stranded in pools during flow recessions that may occur naturally or as a result of dam operations. Past studies have recommended dam operation guidelines that only consider water surface ...elevation (WSE) recession rate to reduce fish stranding potential. Here, we holistically consider the role of flow, WSE recession rate, and river-floodplain topography under unregulated and regulated flow regimes to predict the potential of stranding pool formation. The proposed methodology leverages advances in two-dimensional (2D) surface hydraulic (HD) modeling and high-resolution topobathymetric LiDAR surveys. We applied this method to the South Fork Boise River (SFBR), Idaho, USA. We developed a 2D HD model supported by meter-resolution topobathymetric data to simulate channel and floodplain hydraulics and stranding pool formation for different flow scenarios.
Comparison between modeled and fieldsurveyed stranding pool locations shows good match, supporting the use of this method to predict stranding pool potential. Results show that potential for stranding pool formation (number of pools and their surface area) increases with flow for the same flow recession rate. Contrary to expectations, our model predicts that unregulated flows have a considerably higher number of potential fish stranding pools than for regulated flows in the SFBR. The reach-average WSE recession rates were higher for unregulated (0.07 to 0.09 cm/h) than for regulated (0.02 to 0.04 cm/h) flow based on daily mean flows. Our study has shown the importance of river and floodplain morphology and hydraulics to predict fish stranding pool locations and analyze impacts of flow regulations on fish stranding. This approach may provide helpful information to identify potential fish stranding pools and mitigation and to manage for fish stranding issues in regulated and unregulated river systems.
•Topography, hydrograph and water surface elevation recession rate are important.•Risk of stranding pool formation are site specific and flow dependent.•WSE recession rate and morphology for unregulated and regulated flow.•The tool proposed can be used to evaluate the risk of stranding pool formation.
Investment in sustainable and renewable technologies must be doubled if globally agreed climate targets are to be met. The ways in which stranded asset risk from climate change could impact the ...risk-return preferences and capital allocation decisions is therefore receiving increased attention. We develop an analytical framework to systematically review the literature on stranded asset risk across the investment chain: for physical assets, securities, investment portfolios, the creditworthiness of financial institutions, and the stability of the financial system. We find that there has been a strong focus on evaluating stranding risk for illiquid assets at the earlier points in the investment chain: fossil fuel reserves and the energy generation sector. These studies identify stranding risk for high cost or carbon-intensive reserves and for energy generation technologies dependent on these resources, in particular coal. There is also some evidence that owners of financial assets could also be exposed to stranding risk because the valuations of coal, oil and gas companies could be overstated, particularly for undiversified companies with high capital exposure to carbon-intensive resources. Moving along the investment chain, there are fewer studies quantifying risks for the creditworthiness of counterparties, asset portfolio managers, financial institutions and the stability of the financial system. While there is some evidence that stranding risk may be an issue for financial institutions and investment portfolios, other studies find that risks to more liquid assets are less acute and can be managed by diversification strategies. These are areas meriting further research.
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•Stranded asset risk from climate mitigation affects capital allocation decisions.•Evaluating risks at earlier points in the investment chain has been the main focus.•High cost and carbon-intensive fossil fuel reserves are highly exposed.•Stranding risk could also affect financial institutions and investment portfolios.•Further research is needed to assess risks at later points in the investment chain.
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