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Phthalates are used in plastics, found throughout the marine environment and have the potential to cause adverse health effects. In the present study, we quantified blubber concentrations of 11 phthalates in 16 samples from stranded and/or free-living marine mammals from the Norwegian coast: the killer whale (Orcinus orca), sperm whale (Physeter macrocephalus), long-finned pilot whale (Globicephala melas), white-beaked dolphin (Lagenorhynchus albirostris), harbour porpoise (Phocoena phocoena), and harbour seal (Phoca vitulina). Five compounds were detected across all samples: benzyl butyl phthalate (BBP; in 50 % of samples), bis(2-ethylhexyl) phthalate (DEHP; 33 %), diisononyl phthalate (DiNP; 33 %), diisobutyl phthalate (DiBP; 19 %), and dioctyl phthalate (DOP; 13 %). Overall, the most contaminated individual was the white-beaked dolphin, whilst the lowest concentrations were measured in the killer whale, sperm whale and long-finned pilot whale. We found no phthalates in the neonate killer whale. The present study is important for future monitoring and management of these toxic compounds., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Marine mammals are considered sentinel species and may act as indicators of ocean health. Plastic residues are widely distributed in the oceans and are recognised as hazardous contaminants, and once ingested can cause several adverse effects on wildlife. This study aimed to identify and characterise plastic ingestion in the Guiana dolphins (Sotalia guianensis) from the Southwestern Tropical Atlantic by evaluating the stomach contents of stranded individuals through KOH digestion and identification of subsample of particles by LDIR Chemical Imaging System. Most of the individuals were contaminated, and the most common polymers identified were PU, PET and EVA. Microplastics were more prevalent than larger plastic particles (meso- and macroplastics). Smaller particles were detected during the rainy seasons. Moreover, there was a positive correlation between the stomach content mass and the number of microplastics, suggesting contamination through trophic transfer., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Combining mercury and stable isotope data sets of consumers facilitates the quantification of whether contaminant variation in predators is due to diet, habitat use and/or environmental factors. We investigated inter-species variation in total Hg (THg) concentrations, trophic magnification slope between δ 15 N and THg, and relationships of THg with δ 13 C and δ 34 S in 15 fish and four marine mammal species (249 individuals in total) in coastal Arctic waters. Median THg concentration in muscle varied between species ranging from 0.08 ± 0.04 μg g -1 dw in capelin to 3.10 ± 0.80 μg g -1 dw in beluga whales. Both δ 15 N (r 2  = 0.26) and δ 34 S (r 2  = 0.19) best explained variation in log-THg across consumers. Higher THg concentrations occurred in higher trophic level species that consumed more pelagic-associated prey than consumers that rely on the benthic microbial-based food web. Our study illustrates the importance of using a multi-isotopic approach that includes δ 34 S when investigating trophic Hg dynamics in coastal marine systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The Antarctic is particularly sensitive to mercury (Hg) pollution and even low levels of Hg may cause significant damage in this fragile environment. The aim of this study was to investigate routes of mercury and methylmercury (MeHg) elimination by animals inhabiting the maritime Antarctic. The results showed that organisms at the highest trophic level (elephant seal) have the highest concentrations of THg and MeHg in both excrement and fur samples. Interspecies differences in mercury levels were observed in materials sourced from penguins of the genus Pysgocelis. 13 C and 15 N values confirmed differences in the diets and foraging areas, which may affect Hg concentration in the tissues we analyzed. Time variations in THg and MeHg concentrations were observed in the excrement of the penguin species, which may be due to periods of fasting and intense feeding closely related to egg laying and moulting stages., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Ringed seals (Pusa hispida) play a crucial role in Arctic food webs as important pelagic predators and represent an essential component of Inuvialuit culture and food security. Plastic pollution is recognized as a global threat of concern, and Arctic regions may act as sinks for anthropogenic debris. To date, mixed evidence exists concerning the propensity for Canadian Arctic marine mammals to ingest and retain plastic. Our study builds on existing literature by offering the first assessment of plastic ingestion in ringed seals harvested in the western Canadian Arctic. We detected no evidence of microplastic (particles ≥80 μm) retention in the stomachs of ten ringed seals from the Inuvialuit Settlement Region (ISR) in the Northwest Territories, Canada. These results are consistent with previous studies that have found that some marine mammals do not accumulate microplastics in evaluated regions., Competing Interests: Declaration of competing interest The authors have no competing interests that could have influenced the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Microplastics (MPs, < 5 mm in size) are highly bioavailable to many taxa within the marine ecosystem, either ingested directly or indirectly through trophic transfer from polluted prey. The ingestion analysis of these MPs from top predators, such as pinnipeds in Mexico, is relatively unexplored. Forty-eight scats from California sea lions were collected on six rookeries along the Gulf of California. From these scat samples, 294 suspected MPs particles were classified and chemically analyzed; 34% were synthetic and semi-synthetic, and 66% were non-synthetic. Blue-colored polyethylene terephthalate fibers were the most common type of MP registered. During laboratory work, multiple contamination control measures were implemented. Although the ingestion pathway is still unknown, our results support the other authors that suggest the potential trophic transfer of MPs to top predators and incidental ingestion while foraging. The particles documented here provide important baseline information for future MP research in the Gulf of California., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Plastic debris is of particular concern due to its abundance, and its persistence in the environment. In Argentina, the impact of plastic debris has been documented with a significant increase during the last years. However, evidence of debris ingestion remains low compared to other regions of the world. Between 2020 and 2022, one of the twenty-three individuals analyzed in this study (seven species: five birds and two marine mammals) had ingested plastic debris. A single macroplastic piece was found in the Great Grebe (Podiceps major). It was a hardy yellow elastic band that appears to be a packaging band in agreement with the debris category with the greatest number of reports. This study is a contribution to the few records of plastic ingestion in birds, on the east coast of South America., Competing Interests: Declaration of competing interest The authors declare not to have any interest conflicts., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Pinnipeds are sentinel species for marine pollution, but their role as vectors of trace elements (TEs) or rare earth elements (REEs) to ecosystems has been poorly studied. The present study tested pinniped feces for 61 elements, including REEs. Feces of adult seals (Mirounga leonina, Hydrurga leptonyx) from Fildes Bay, King George Island, Antarctica, were analyzed by ICP-MS. TEs varied by several orders of magnitude across the suite examined herein, with Fe, Al, Zn, Mn, HgII and Sr as the top six in both species. Of the REEs, Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sc, Sm, Tb, Y and Yb were found consistently in all samples and ranged from 0.935 to 0.006 μg g -1 d.w. The results show that both species act as biovector organisms of TEs and REEs through feces in remote environments, whose actual impacts and long-term fate need further exploration., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Marine pollution is increasing, and pinnipeds are commonly affected by entanglement in waste. We investigated entanglement rates, common materials, and the demographic profile of Cape fur seals (Arctocephalus pusillus pusillus) affected at two Namibian colonies. Overall, we identified 366 cases of entanglement, and present a global rate of entanglement of 0.17%. Entanglement rates were 0.17% and 0.15% for the Pelican Point and Cape Cross colonies, respectively. We identified 17% more entanglements through photographs than binocular scans. Of the 347 entanglements analysed in detail, juveniles were most commonly affected and fishing materials were the primary cause of entanglements (53%), with 8% of entangled seals exhibiting 'very severe' injuries. Overall, 191 individuals were successfully disentangled, and citizen scientists contributed 51% of total entanglement data. We highlight the negative impact of plastic marine waste among seals and the importance of disentanglement for individual animal welfare., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Marine fauna in the California Current System is susceptible to entanglement in anthropogenic debris. We examined beach survey data from six California counties to describe trends of entangled marine birds and mammals (1997-2017). Surveyors reported 357 cases of entanglements among 65,604 carcasses. Monterey County had the greatest average entanglement rate (0.007) of surveyed counties, however, was not statistically different from Santa Cruz (p > 0.05). Twenty-six seabird species (97%) and three marine mammal species (3%), and three non-marine birds were affected. Numerically, Common Murre (23%), Brandt's Cormorant (13%), Western Gull (9.6%), Sooty Shearwater (8%) and Brown Pelican (7%) were the most affected due to abundance, but their entanglement rates were not statistically different (p > 0.05). The most vulnerable species were those frequently documented as entanglement despite low deposition numbers (Merganser spp. 25%). Entangling material consisted primarily of monofilament line (some hooks/lures), but other entanglement items were reported., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

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., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Oceanic plastic pollution is a growing worldwide environmental concern, endangering numerous marine species. Pinnipeds are particularly susceptible to entanglement, especially in abandoned, lost or discarded fishing gear and packaging straps. We searched three international databases to compile a comprehensive review of all reported pinniped entanglements over the last 40 years, with the aim to identify areas of concern and foci for mitigation. The majority of published records of entanglement emanate from North America and Oceania and are focused on a few populous species (notably, Zalophus californianus and Arctocephalus gazella). Reporting bias, skewed research effort and incomplete understanding of plastic pollution and pinniped abundance overlap, combine to cloud our understanding of the entanglement problem. Broader geographical effort in entanglement data collection, reporting of such data, and improved quantification of the proportions of populations, sexes and ages that are most susceptible, will aid our efforts to pinpoint priority mitigation measures., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Active acoustic sensors are widely used in oceanographic and environmental studies. Although many have nominal operating frequencies above the range of marine mammal hearing, they can produce out-of-band sound that may be audible to marine mammals. Acoustic emissions from four active acoustic transducers were characterized and compared to marine mammal hearing thresholds. All four transducers had nominal operating frequencies above the reported upper limit of marine mammal hearing, but produced measurable sound below 160 kHz. A spatial map of the acoustic emissions of each sonar is used to evaluate potential effects on marine mammal hearing when the transducer is continuously operated from a stationary platform. Based on the cumulative sound exposure level metric, the acoustic emissions from the transducers are unlikely to cause temporary threshold shifts in marine mammals, but could affect animal behavior. The extent of audibility is estimated to be, at most, on the order of 100 m., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Oil spills of unknown origin were detected in three oil-fouled, ice-associated seals from the Alaska Bering Strait region collected by Alaska Native subsistence hunters during fall 2012. Bile analyses of two oiled seals indicated exposure to fluorescent polycyclic aromatic hydrocarbon (PAH) metabolites but levels of some metabolites were similar to or lower than biliary levels in harvested unoiled ice seals. Oiled seals had elevated tissue PAH concentrations compared to tissue levels of PAHs determined in unoiled ice seals. However, regardless of oiling status, tissue PAH levels were relatively low (<50 ng/g, wet weight) likely due to rapid PAH metabolism and elimination demonstrated previously by vertebrates. Hepatic, pulmonary, and cardiac lesions were observed in oiled seals in conjunction with measurable PAHs in their tissue and bile. This is the first study to report tissue and bile PAH concentrations and pathologic findings of oiled ice seals from the U.S. Arctic., (Published by Elsevier Ltd.)

This review focuses on the effect that ghost gear entanglement has on marine megafauna, namely mammals, reptiles and elasmobranchs. A total of 76 publications and other sources of grey literature were assessed, and these highlighted that over 5400 individuals from 40 different species were recorded as entangled in, or associated with, ghost gear. Interestingly, there appeared to be a deficit of research in the Indian, Southern, and Arctic Oceans; and so, we recommend that future studies focus efforts on these areas. Furthermore, studies assessing the effects of ghost gear on elasmobranchs, manatees, and dugongs should also be prioritised, as these groups were underrepresented in the current literature. The development of regional databases, capable of recording entanglement incidences following a minimum global set of criteria, would be a logical next step in order to analyse the effect that ghost gear has on megafauna populations worldwide., (Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.)

Entanglement in and ingestion of synthetic marine debris is increasingly recognized worldwide as an important stressor for marine wildlife, including marine mammals. Studying its impact on wildlife populations is complicated by the inherently cryptic nature of the problem. The coastal waters of British Columbia (BC), Canada provide important habitat for marine mammal species, many of which have unfavorable conservation status in the US and Canada. As a priority-setting exercise, we used data from systematic line-transect surveys and spatial modeling methods to map at-sea distribution of debris and 11 marine mammal species in BC waters, and to identify areas of overlap. We estimated abundance of 36,000 (CIs: 23,000-56,600) pieces of marine debris in the region. Areas of overlap were often far removed from urban centers, suggesting that the extent of marine mammal-debris interactions would be underestimated from opportunistic sightings and stranding records, and that high-overlap areas should be prioritized by stranding response networks., (Copyright © 2011 Elsevier Ltd. All rights reserved.)