Anthropogenic litter in terrestrial flora and fauna: Is the situation as bad as in the ocean? A field study in Southern Germany on five meadows and 150 ruminants in comparison with marine debris

In contrast to the abundance of research on marine debris, terrestrial anthropogenic litter and its impacts are largely lacking scientific attention. Therefore, the main objective of the present study is to find out whether ingested litter produces pathological consequences to the health of domestic ruminants, as it does in their relatives in the ocean, the cetaceans. For this purpose, five meadows (49°18'N, 10°24'E) with a total survey area of 139,050 m² as well as the gastric content of 100 slaughtered cattle and 50 slaughtered sheep have been examined for persistent man-made debris in Northern Bavaria, Germany. All the five meadows contained garbage, and plastics were always part of it. Including glass and metal, 521 persistent anthropogenic objects were detected altogether, equalling a litter density of 3747 items per km². Of the examined animals, 30.0% of the cattle and 6.0% of the sheep harboured anthropogenic foreign bodies in their gastric tract. As in the case of cetaceans, plastics were the most dominant litter material. Bezoars had formed around plastic fibres of agricultural origin in two young bulls, whereas pointed metal objects were associated in cattle with traumatic lesions in the reticulum and the tongue. Of all the ingested anthropogenic debris, 24 items (26.4%) had direct equivalents in the studied meadows. Comparing with marine litter, 28 items (30.8%) were also present in marine environments and 27 items (29.7%) were previously reported as foreign bodies in marine animals. At least in this study region, waste pollution affected terrestrial environments and domestic animals, with clear equivalents in the marine world. Ingested foreign bodies produced lesions that may have reduced the animals' welfare and, regarding commercial purposes, their productivity.

The use of social media in assessing the impact of war on cetaceans

War has always brought millions of silent non-human victims but the scale of this suffering is often either unknown, neglected or difficult to quantify. Further, the complexities associated with long-term and large-scale monitoring of marine species make it difficult to assess the impacts of war and the mortality of cetaceans resulting from warfare has not been investigated. Here we propose the use of a modified form of citizen science, namely gathering the information from social media. Dolphin stranding is such a poignant incident for most people, that the probability of eyewitness posting information on social media appears high. We test this idea by collecting data on cetacean strandings along the Black Sea published on the Internet over the three months of Russia's invasion of Ukraine in 2022. We also validate this method with a small-scale scientific study on cetacean mortality during the same period of time, conducted in 'Tuzlivski lymany' Nature National Park in Ukraine. Our dual approach has produced similar results, indicating a dramatic increase in cetacean mortality due to war operations in the Black Sea. We advocate the future use of social media to bridge the knowledge gap on the impacts of war on animals, in particular cetaceans.

Evaluation of a marine mammal status and trends contaminants indicator for European waters

Marine mammals are vulnerable to the bioaccumulation, biomagnification and lactational transfer of specific types of pollutants, such as industrial polychlorinated biphenyls (PCBs), due to their long-life spans, feeding at a high trophic level and unique fat stores that can serve as depots for these lipophilic contaminants. Currently, European countries are developing indicators for monitoring pollutants in the marine environment and assessing the state of biodiversity, requirements under both Regional Seas Conventions and European legislation. As sentinel species for marine ecosystem and human health, marine mammals can be employed to assess bioaccumulated contaminants otherwise below current analytical detection limits in water and lower trophic level marine biota. To aid the development of Regional Seas marine mammal contaminants indicators, as well as Member States obligations under descriptor 8 of the EU Marine Strategy Framework Directive, the current study aims to further develop appropriate methodological standards using data collected by the established UK marine mammal pollutant monitoring programme (1990 to 2017) to assess the trends and status of PCBs in harbour porpoises. Within this case study, temporal trends of PCB blubber concentration in juvenile harbour porpoises were analysed using multiple linear regression models and toxicity thresholds for the onset of physiological (reproductive and immunological) endpoints were applied to all sex-maturity groups. Mean PCB blubber concentrations were observed to decline in all harbour porpoise Assessment Units and OSPAR Assessment Areas in UK waters. However, a high proportion of animals were exposed to concentrations deemed to be a toxicological threat, though the relative proportion declined in most Assessment Units/Areas over the last 10 years of the assessment. Recommendations were made for improving the quality of the assessment going forward, including detailing monitoring requirements for the successful implementation of such an indicator.

No accumulation of microplastics detected in western Canadian ringed seals (Pusa hispida)

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.

Controllable acoustic deterrent based on the warning signals generated by nonel detonators

Acoustic deterrents are a practical strategy to mitigate the impact of underwater noise on marine mammals. However, their safety and effectiveness are still debatable. This study proposes a controllable acoustic deterrence method to protect marine mammals threatened by underwater blasting noise. The method creates strong-randomness warning signals using nonel detonators and establishes an escape time for animals protected. Combining the BELLHOP ray-based acoustic model with the marine environmental parameters and animals' auditory characteristics, we built a prediction model to establish a link between the acoustic fields and the adjustable source parameters, and provide a Risk zone and Deterrent zone for animals. The simulation and experimental results demonstrated that the root mean squared error between the simulated and measured sound pressure spectral density levels did not exceed 4.5 dB and the coefficient of determination remained at approximately 0.8, indicating that the new deterrent is an effective method with good controllable performances.

Emerging and legacy contaminants in common minke whale from the Barents sea

Persistent organic pollutants (POPs), including brominated flame retardants (BFRs), perfluoroalkyl substances (PFAS) and metals, can accumulate in marine mammals and be transferred to offspring. In this study, we analyzed 64 lipophilic POPs, including four emerging BFRs, in the blubber, liver and muscle of 17 adult common minke whales (Balaenoptera acutorostrata) from the Barents Sea to investigate occurrence and tissue partitioning. In addition, the placental transfer concentration ratios of 14 PFAS and 17 metals were quantified in the muscle of nine female-fetus pairs to investigate placental transfer. Legacy lipophilic POPs were the dominating compound group in every tissue, and we observed generally lower levels compared to previous studies from 1992 to 2001. We detected the emerging BFRs hexabromobenzene (HBB) and pentabromotoluene (PBT), but in low levels compared to the legacy POPs. We detected nine PFAS, and levels of perfluorooctane sulfonate (PFOS) were higher than detected from the same population in 2011, whilst levels of Hg were comparable to 2011. Levels of lipophilic contaminants were higher in blubber compared to muscle and liver on both a wet weight and lipid adjusted basis, but tissue partitioning of the emerging BFRs could not be determined due to the high number of samples below the limit of detection. The highest muscle ΣPFAS levels were quantified in fetuses (23 ± 8.7 ng/g ww), followed by adult males (7.2 ± 2.0 ng/gg ww) and adult females (4.5 ± 1.1 ng/g ww), showing substantial placental transfer from mother to fetus. In contrast, Hg levels in the fetus were lower than the mother. Levels were under thresholds for risk of health effects in the whales. This study is the first to report occurrence and placental transfer of emerging contaminants in common minke whales from the Barents Sea, contributing valuable new data on pollutant levels in Arctic wildlife.

Environmental variables and machine learning models to predict cetacean abundance in the Central-eastern Mediterranean Sea

Although the Mediterranean Sea is a crucial hotspot in marine biodiversity, it has been threatened by numerous anthropogenic pressures. As flagship species, Cetaceans are exposed to those anthropogenic impacts and global changes. Assessing their conservation status becomes strategic to set effective management plans. The aim of this paper is to understand the habitat requirements of cetaceans, exploiting the advantages of a machine-learning framework. To this end, 28 physical and biogeochemical variables were identified as environmental predictors related to the abundance of three odontocete species in the Northern Ionian Sea (Central-eastern Mediterranean Sea). In fact, habitat models were built using sighting data collected for striped dolphins Stenella coeruleoalba, common bottlenose dolphins Tursiops truncatus, and Risso's dolphins Grampus griseus between July 2009 and October 2021. Random Forest was a suitable machine learning algorithm for the cetacean abundance estimation. Nitrate, phytoplankton carbon biomass, temperature, and salinity were the most common influential predictors, followed by latitude, 3D-chlorophyll and density. The habitat models proposed here were validated using sighting data acquired during 2022 in the study area, confirming the good performance of the strategy. This study provides valuable information to support management decisions and conservation measures in the EU marine spatial planning context.

POPs concentrations in cetaceans stranded along the agricultural coastline of SE Spain show lower burdens of industrial pollutants in comparison to other Mediterranean cetaceans

Despite the Mediterranean Sea being one of the world's marine biodiversity hotspots, it is a hotspot of various environmental pollutants. This sea holds eight cetacean with resident populations whose numbers are considered to decline in the last decades and which are particularly susceptible to POPs bioaccumulation due to their peculiar characteristics. In this work, we studied blubber concentration of various OCPs and several PCBs and PBDEs congeners in cetaceans stranded in the northern coast of the Gulf of Vera (Region of Murcia, SE Spain) between 2011 and 2018. Most compounds and congeners were above the limit of detection in most samples, although some pesticides like endosulfan stereoisomers or endrin were never detected. DDT and its metabolites, PCBs and metoxychlor appear as the dominant compounds while PBDEs shows concentrations of lower magnitude. Striped dolphin was the species accounting for higher concentrations of most pollutants. There were differences in concentrations and profiles between species which could be partially explained by differences on diet and feeding behavior. We also observed differences based on life history parameters suggesting maternal transfer for most POPs, in accordance with other works. DDE/ ΣDDT ratio suggest no recent exposure to these pesticides. Despite showing lower concentrations than some previous works, PCB concentrations accounted for higher total TEQ than many studies. According to toxicity thresholds in the literature, we cannot guarantee the absence of health consequences on populations studied, especially for those caused by PCBs. These findings are of major importance considering the relevance of the study area in the conservation of Mediterranean cetaceans.

Fault diagnosis and prediction of wind turbine gearbox based on a new hybrid model

Gearbox is an important part of wind turbine. Diagnosing and forecasting gearbox faults of wind turbines can effectively reduce the costs of operation and maintenance and improve the reliability of gearbox operation. Due to high dimensionality and nonlinearity of system parameters, the paper uses the grey relation analysis to select features related to gearbox oil temperature. Features with a relational degree above 0.7 are selected as input data related to oil temperature, including wind speed, ambient temperature, power, and gearbox shaft temperature. Then, a new extreme learning machine with kernel improved by the whale optimization algorithm is established to forecast gearbox oil temperature. Through the residuals between gearbox oil temperature predicted by the proposed model and monitored by the SCADA, whether the gearbox exists faults can be diagnosed. In the case study, the test data was divided into two groups (the test data with and without faults). In the data test without faults, compared with three other models, the proposed model has the smallest false-negative rate (0.211%) and mean absolute percentage error (2.812%). In the data test with faults, the proposed model can diagnose gearbox faults earlier (160 min in advance) than the other three benchmark models. The results show that the proposed hybrid model performs well in the fault diagnosis and prediction of wind turbine gearbox.

Latencies of click-evoked auditory responses in a harbor porpoise exceed the time interval between subsequent echolocation clicks

Most auditory evoked potential (AEP) studies in echolocating toothed whales measure neural responses to outgoing clicks and returning echoes using short-latency auditory brainstem responses (ABRs) arising a few ms after acoustic stimuli. However, little is known about longer-latency cortical AEPs despite their relevance for understanding echo processing and auditory stream segregation. Here, we used a non-invasive AEP setup with low click repetition rates on a trained harbor porpoise to test the long-standing hypothesis that echo information from distant targets is completely processed before the next click is emitted. We reject this hypothesis by finding reliable click-related AEP peaks with latencies of 90 and 160 ms, which are longer than 99% of click intervals used by echolocating porpoises, demonstrating that some higher-order echo processing continues well after the next click emission even during slow clicking. We propose that some of the echo information, such as range to evasive prey, is used to guide vocal-motor responses within 50-100 ms, but that information used for discrimination and auditory scene analysis is processed more slowly, integrating information over many click-echo pairs. We conclude by showing theoretically that the identified long-latency AEPs may enable hearing sensitivity measurements at frequencies ten times lower than current ABR methods.

Potential biases in dietary interpretation derived from stable isotope analysis of small dolphin teeth

We analyzed δ¹³C and δ¹⁵N values in different tooth portions (Growth Layer Groups, GLGs) of franciscanas, Pontoporia blainvillei, to investigate their effect on whole tooth (WT) isotopic values and the implications for dietary estimates. Tooth portions included the dentin deposited during the prenatal development (PND), the first year of life (GLG₁) deposited during the nursing period and the central part of the tooth with no distinction amongst subsequent GLGs (Center). Isotopic mixing models estimating the contribution of PND, GLG₁ and Center to WT showed that GLG₁ has a strong effect on WT isotope values in juveniles, while Center only starts to affect WT isotopic values from age four. Isotopic mixing models estimating prey contribution to the diet of juveniles using WT vs Center tooth portions significantly differed in dietary outputs, demonstrating that GLG₁ influence on WT isotope values affects dietary estimates in young franciscanas. As the small tooth size and narrowness of the last GLGs hinder the analysis of individual layers, we recommend excluding GLG₁ in studies based on teeth isotope composition in franciscanas and caution when interpreting isotopic values from the WT of other small cetaceans.

Ecological impacts of unsustainable sand mining: urgent lessons learned from a critically endangered freshwater cetacean

Sand mining, which has tripled in the last two decades, is an emerging concern for global biodiversity. However, the paucity of sand mining data worldwide prevents understanding the extent of sand mining impacts and how it affects wildlife populations and ecosystems, which is critical for timely mitigation and conservation actions. Integrating remote sensing and field surveys over 14 years, we investigated mining impacts on the critically endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) in Dongting Lake, China. We found that sand mining presented a consistent, widespread disturbance in Dongting Lake. Porpoises strongly avoided mining sites, especially those of higher mining intensity. The extensive sand mining significantly contracted the porpoise's range and restricted their habitat use in the lake. Water traffic for sand transportation further blocked the species's river-lake movements, affecting the population connectivity. In addition, mining-induced loss of near-shore habitats, a critical foraging and nursery ground for the porpoise, occurred in nearly 70% of the water channels of our study region. Our findings provide the first empirical evidence of the impacts of unregulated sand extractions on species distribution. Our spatio-temporally explicit approach and findings support regulation and conservation, yielding broader implications for sustainable sand mining worldwide.

Emergent interactions in the management of multiple threats to the conservation of harbour porpoises

Human activities at sea are intensifying and diversifying. This is leading to more complex interactions of anthropogenic impacts requiring adaptable management interventions to mitigate their cumulative effects on biodiversity conservation and restoration objectives. Bycatch remains the dominant conservation threat for coastal cetaceans. Additionally, the indirect impact of repeated exposure to disturbances, particularly acoustic disturbances, can affect cetacean population growth and therefore conservation objectives. Pingers are used to ensonify nets to provide an effective mitigation of bycatch risk. As those become more prevalent across fisheries at risk to catch for example harbour porpoises, pingers become contributors to the anthropogenic noise landscape which may affect the vital rates of this species as well. Currently, we do not know how to best balance pinger prevalence to minimise both bycatch rate and the population consequences of acoustic disturbance (PCoD). Here we use an agent-based model to determine how pinger prevalence in nets can be adjusted to minimise bycatch rate and noise disturbance propagating to affect population growth for harbour porpoises. We show that counter-intuitively bycatch rate can increase at lower pinger prevalence. When ecological conditions are such that PCOD can emerge, higher prevalence of pingers can lead to indirect effects on population growth. This would result from condition-mediated decreased reproductive potential. Displacing fishing effort, via time-area closure, can be an effective mitigation strategy in these circumstances. These findings have important implications for current management plans which, for practical consideration, may lead to lower overall pinger prevalence at sea. This study also shows that estimating the reproductive potential of the species should be incorporated in bycatch monitoring programmes. We now need to better understand how physiological condition affect reproductive decisions and behavioural responses to noise in cetaceans to better appraise and estimate the cumulative impacts of bycatch and its mitigations.

Integrating technologies provides insight into the subsurface foraging behaviour of a humpback whale (Megaptera novaeangliae) feeding on walleye pollock (Gadus chalcogrammus) in Juan de Fuca Strait, Canada

Subsurface foraging is an important proportion of the activity budget of rorqual whales, yet information on their behaviour underwater remains challenging to obtain. Rorquals are assumed to feed throughout the water column and to select prey as a function of depth, availability and density, but there remain limitations in the precise identification of targeted prey. Current data on rorqual foraging in western Canadian waters have thus been limited to observations of prey species amenable to surface feeding, such as euphausiids and Pacific herring (Clupea pallasii), with no information on deeper alternative prey sources. We measured the foraging behaviour of a humpback whale (Megaptera novaeangliae) in Juan de Fuca Strait, British Columbia, using three complimentary methods: whale-borne tag data, acoustic prey mapping, and fecal sub-sampling. Acoustically detected prey layers were near the seafloor and consistent with dense schools of walleye pollock (Gadus chalcogrammus) distributed above more diffuse aggregations of pollock. Analysis of a fecal sample from the tagged whale confirmed that it had been feeding on pollock. Integrating the dive profile with the prey data revealed that the whale's foraging effort followed the general pattern of areal prey density, wherein the whale had a higher lunge-feeding rate at the highest prey abundance and stopped feeding when prey became limited. Our findings of a humpback whale feeding on seasonally energy-dense fish like walleye pollock, which are potentially abundant in British Columbia, suggests that pollock may be an important prey source for this rapidly growing whale population. This result is informative when assessing regional fishing activities for semi-pelagic species as well as the whales' vulnerability to fishing gear entanglements and feeding disturbances during a narrow window of prey acquisition.

Consequences of in vitro benzyl butyl phthalate exposure for blubber gene expression and insulin-induced Akt activation in juvenile grey seals

Plastic and plasticiser pollution of marine environments is a growing concern. Although phthalates, one group of plasticisers, are rapidly metabolised by mammals, they are found ubiquitously in humans and have been linked with metabolic disorders and altered adipose function. Phthalates may also present a threat to marine mammals, which need to rapidly accumulate and mobilise their large fat depots. High molecular weight (HMW) phthalates may be most problematic because they can accumulate in adipose. We used blubber explants from juvenile grey seals to examine the effects of overnight exposure to the HMW, adipogenic phthalate, benzyl butyl phthalate (BBzP) on expression of key adipose-specific genes and on phosphorylation of Akt in response to insulin. We found substantial differences in transcript abundance of Pparγ, Insig2, Fasn, Scd, Adipoq and Lep between moult stages, when animals were also experiencing differing mass changes, and between tissue depths, which likely reflect differences in blubber function. Akt abundance was higher in inner compared to outer blubber, consistent with greater metabolic activity in adipose closer to muscle than skin, and its phosphorylation was stimulated by insulin. Transcript abundance of Pparγ and Fasn (and Adipoq in some animals) were increased by short term (30 min) insulin exposure. In addition, overnight in vitro BBzP exposure altered insulin-induced changes in Pparγ (and Adipoq in some animals) transcript abundance, in a tissue depth and moult stage-specific manner. Basal or insulin-induced Akt phosphorylation was not changed. BBzP thus acted rapidly on the transcript abundance of key adipose genes in an Akt-independent manner. Our data suggest phthalate exposure could alter seal blubber development or function, although the whole animal consequences of these changes are not yet understood. Knowledge of typical phthalate exposures and toxicokinetics would help to contextualise these findings in terms of phthalate-induced metabolic disruption risk and consequences for marine mammal health.

An unknown nocturnal call type in the Mariana Archipelago

In spring/summer of 2018 and 2021, the Pacific Islands Fisheries Science Center Cetacean Research Program deployed drifting acoustic recorders in the U.S. Exclusive Economic Zones surrounding the Mariana Archipelago. Manual assessments revealed a low-frequency (median 473-554 Hz), short-duration (median 0.596 s), stereotypic tonal nocturnal call throughout the Mariana Archipelago. Based on time of year, spatiotemporal patterns, clear division among calls (i.e., no chorusing), comparisons with known vocalizations of whales, turtles, and fish, and presence of Bryde's whale calls, and because the call has not been detected elsewhere, we hypothesize this 500-Hz pulsed call is produced by Bryde's whales (Balaenoptera brydei).

Comprehensive non-target screening of biomagnifying organic contaminants in the Baltic Sea food web

High-resolution mass spectrometry (HRMS) based non-target screening (NTS) is a powerful approach for the simultaneous determination of multiple environmental contaminant classes in complex biota samples. In this study, trophic biomagnification factor (TMF) directed NTS was performed to find and (tentatively) identify known, emerging, and new chemical contaminants that are persistent and biomagnify in Baltic Sea biota. The investigated food web included seven species: one filter feeder (blue mussel, Mytilus edulis), two fish (eelpout, Zoarces viviparous; herring, Clupea harengus), two marine mammals (harbor porpoise, Phocoena phocoena; grey seal, Halichoerus grypus) and two birds (guillemot, Uria aalge; white-tailed sea eagle, Haliaeetus albicilla). The NTS procedure included extraction with organic solvent mixtures, two-step high-resolution gel permeation chromatography clean-up, Florisil® fractionation, gas chromatography (GC) HRMS analysis in electron ionization (EI) and electron capture negative ion chemical ionization (ECNI) modes, and NTS data processing. The latter was performed differently for the EI and ECNI data: the EI data were treated using a flexible and highly automated TMF-directed NTS workflow, whereas the ECNI data were treated with a simpler and less automated workflow that specifically screened for brominated compounds. The two workflows collectively revealed biomagnification (statistically significant TMF values) of >250 tentatively identified compounds, including legacy persistent organic pollutants (POPs), such as PCBs and PCB-related compounds, DDT and its metabolites, and organochlorine pesticides (OCPs), contaminants of emerging concern (CECs), and halogenated natural products (HNPs). Among the tentatively identified CECs, nine have not previously been reported in environmental biota samples. These included four polymer additives (used as antioxidants, rubber additives or plasticizers) and two cosmetic product additives (ethyl myristate and isopropyl palmitate). The CECs should be prioritized for future structure verification and quantification using reference standards.

Monitoring macroplastic ingestion by birds and marine mammals in northeastern Patagonia, Argentina

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.

Silbido profundo: An open source package for the use of deep learning to detect odontocete whistles

This work presents an open-source matlab software package for exploiting recent advances in extracting tonal signals from large acoustic data sets. A whistle extraction algorithm published by Li, Liu, Palmer, Fleishman, Gillespie, Nosal, Shiu, Klinck, Cholewiak, Helble, and Roch [(2020). Proceedings of the International Joint Conference on Neural Networks, July 19-24, Glasgow, Scotland, p. 10] is incorporated into silbido, an established software package for extraction of cetacean tonal calls. The precision and recall of the new system were over 96% and nearly 80%, respectively, when applied to a whistle extraction task on a challenging two-species subset of a conference-benchmark data set. A second data set was examined to assess whether the algorithm generalized to data that were collected across different recording devices and locations. These data included 487 h of weakly labeled, towed array data collected in the Pacific Ocean on two National Oceanographic and Atmospheric Administration (NOAA) cruises. Labels for these data consisted of regions of toothed whale presence for at least 15 species that were based on visual and acoustic observations and not limited to whistles. Although the lack of per whistle-level annotations prevented measurement of precision and recall, there was strong concurrence of automatic detections and the NOAA annotations, suggesting that the algorithm generalizes well to new data.

Recreational boating as a potential stressor of coastal striped dolphins in the northwestern Mediterranean Sea

Striped dolphin (Stenella coeruleoalba) is the most abundant cetacean species in the western Mediterranean Sea. Coastal populations are locally exposed to intense recreational boating, a growing activity over the last thirty years. Dedicated boat surveys carried out since 1988 (13,896 km of effort), enabled to map relative abundance for two periods, 1988-2003 and 2004-2019, which evidenced a significant decrease of habitat use in the inshore part of study area. Coastal traffic was surveyed from a shore lookout located in Cap d'Antibes (French Riviera) during 47 daily sessions from May 2017 to April 2018: traffic flow often exceeded one boat per minute in summer, with a majority of motorboats. Underwater recordings showed that inshore noise was about 10 dB higher than in the open sea, with much energy being propagated by fast boats, including in the medium to high frequency domain. Ambient noise data collected during spring 2020 lockdown evidenced a clear noise level decrease compared to normal situations. Although other stressors may not be neglected, this study suggested that intense motorboat traffic is a likely contributor to the observed striped dolphin partial habitat loss.

A novel hybrid optimization enabled robust CNN algorithm for an IoT network intrusion detection approach

Due to the huge number of connected Internet of Things (IoT) devices within a network, denial of service and flooding attacks on networks are on the rise. IoT devices are disrupted and denied service because of these attacks. In this study, we proposed a novel hybrid meta-heuristic adaptive particle swarm optimization-whale optimizer algorithm (APSO-WOA) for optimization of the hyperparameters of a convolutional neural network (APSO-WOA-CNN). The APSO-WOA optimization algorithm's fitness value is defined as the validation set's cross-entropy loss function during CNN model training. In this study, we compare our optimization algorithm with other optimization algorithms, such as the APSO algorithm, for optimization of the hyperparameters of CNN. In model training, the APSO-WOA-CNN algorithm achieved the best performance compared to the FNN algorithm, which used manual parameter settings. We evaluated the APSO-WOA-CNN algorithm against APSO-CNN, SVM, and FNN. The simulation results suggest that APSO-WOA-CNf[N is effective and can reliably detect multi-type IoT network attacks. The results show that the APSO-WOA-CNN algorithm improves accuracy by 1.25%, average precision by 1%, the kappa coefficient by 11%, Hamming loss by 1.2%, and the Jaccard similarity coefficient by 2%, as compared to the APSO-CNN algorithm, and the APSO-CNN algorithm achieves the best performance, as compared to other algorithms.

Detection of faults and DG islanding in PV-Wind DC ring bus microgrid by using optimized VMD based improved broad learning system

This paper presents a novel approach for the detection and classification of photovoltaic with wind based DC ring bus microgrid DC faults and DG (distributed generation) islanding events. This novel approach consists of adaptive variational mode decomposition (AVMD) and an improved broad learning system (IBLS). Initially, DC fault current signals are captured from the DC bus under different operating conditions and processed through the AVMD to decompose the signals into intrinsic mode functions (IMFs). The VMD is made adaptive by minimizing the objective function of the L-kurtosis index for optimal modal number (K) and penalty factor (σ) through the improved whale optimization (IWO) algorithm. From the optimal IMFs, the most significant IMFs are chosen based on the threshold of the L-kurtosis index, and they are passed through statistical features to extract efficient data. Further, the training and testing of this data set is carried out through IBLS for obtaining the accurate detection and discrimination of DC faults. The conventional BLS method is improved through elastic net ridge regression for calculating the weights. The effectiveness of the proposed AVMD based IBLS algorithm is verified by its superiority in terms of relative computation time (RCT), classification accuracy (CA) with the confusion matrix, and their performance indices by comparing with other existing methods under different case studies. Finally, the simplicity and practicability of the proposed work are tested and implemented in the dSPACE 1104 embedded processor.

Prevalence and genotype of Toxoplasma gondii in stranded Hawaiian cetaceans

Toxoplasma gondii is a significant threat to endangered Hawaiian wildlife including birds and marine mammals. To estimate the prevalence of T. gondii in stranded cetaceans from 1997 to 2021 in Hawai'i, we tested tissues from 37 stranded spinner dolphins Stenella longirostris and 51 stranded individuals that represented 18 other cetacean species. DNA from cetacean tissue extracts were screened using a nested polymerase chain reaction (PCR) assay targeting the Toxoplasmatinae internal transcribed spacer 1 of the nuclear ribosomal DNA. A positive result was obtained in 9 tissues examined for each of 2 spinner dolphins out of 525 tissue samples analyzed by PCR. The PCR-positive spinner dolphins had disseminated acute toxoplasmosis with necrosis, inflammation, and intralesional protozoal cysts and tachyzoites in multiple organs. Discrete positive immunostaining for T. gondii was observed in all tissues tested including the adrenal gland, brain, liver, and lung. Both positive spinner dolphins were negative for cetacean morbillivirus. The T. gondii genotyping was performed by restriction fragment length polymorphism (PCR-RFLP) based on 10 genetic markers. The PCR-RFLP analysis revealed the T. gondii belonged to PCR-RFLP-ToxoDB genotype #24, previously detected in wild pig Sus scrofa in O'ahu, bobcats Lynx rufus from Mississippi, USA, and chickens Gallus gallus from Costa Rica and Brazil. These cases represent the first report of this genotype in aquatic mammals and the second and third reports of fatal disseminated T. gondii infection in stranded spinner dolphins from Hawai'i. Nearshore species, like spinner dolphins, may be at increased risk of mortality from this parasite in marine coastal waterways via sewage systems, storm water drainage, and freshwater runoff.

Tissue distribution and trophic magnification of trace elements in typical marine mammals in Bohai and north Yellow Seas

A total of 20 stranded spotted seals (Phoca largha) and 9 stranded minke whales (Balaenoptera acutorostrata) were collected from Liaodong Bay and the northern part of the Yellow Sea to investigate the tissue distribution (liver, kidney, heart, lung, and muscle), risk, and trophic magnification of 13 trace elements (TEs, Hg, As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Se, Sn, V, Zn). The 13 TEs were all detected in all spotted seal and minke whale tissue samples, with mean concentrations ranging from 0.041 to 136.3 mg kg^-1 dry weight (dw) and 0.022 to 152.6 mg kg^-1 dw, respectively. Zn was the dominant contaminant in all tissues for both spotted seals and minke whales. There was tissue-specific distribution of TEs in both marine mammals, and the TEs tended to accumulate in internal organs. Significant positive correlations were found in the body length of the spotted seals and minke whales among some of the TEs, especially for Cd in the internal organs. Gender-dependent distribution of the TEs was not obtained for the spotted seal. Ecological risk evaluation for spotted seals and minke whales suggested that greater concern should be given to Hg, As, and Se. Based on the TE concentrations detected in this study and trophic levels determined by stable carbon and nitrogen isotopes, trophic level-associated biodilution was obtained for As, Cd, Co, Cu, Mn, Pb, Se, Sn, and V in the spotted seal, while Zn displayed a significant biomagnification trend with increasing trophic levels. In the case of the minke whale, As, Cd, Co, Mn, Pb, Se, and V displayed significant biomagnification trends with increasing trophic levels.

Dredging activity in a highly urbanised estuary did not affect the long-term occurrence of Indo-Pacific bottlenose dolphins and long-nosed fur seals

Dredging is an excavation activity used worldwide in marine and freshwater environments to create, deepen, and maintain waterways, harbours, channels, locks, docks, berths, river entrances, and approaches to ports and boat ramps. However, dredging impacts on marine life, including marine mammals (cetaceans, pinnipeds, and sirenians), remain largely unknown. Here we quantified the effect of dredging operations in 2005 and 2019 on the occurrence of Indo-Pacific bottlenose dolphins (Tursiops aduncus) and long-nosed fur seals (Arctocephalus forsteri) in the Port River estuary, a highly urbanized estuary in Adelaide, South Australia. We applied generalised linear models to two long-term sighting datasets (dolphins: 1992-2020, fur seals: 2010-2020), to analyse changes in sighting rates as a function of dredging operations, season, rainfall, and sea surface temperature. We showed that the fluctuations in both dolphin and fur seal occurrences were not correlated with dredging operations, whereas sea surface temperature and season were stronger predictors of both species sighting rates (with seals more prevalent during the colder months, and dolphins in summer). Given the highly industrial environment of the Port River estuary, it is possible that animals in this area are habituated to high noise levels and therefore were not disturbed by dredging operations. Future research would benefit from analysing short-term effects of dredging operations on behaviour, movement patterns and habitat use to determine effects of possible habitat alteration caused by dredging.