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Shipping is the most pervasive source of marine noise pollution globally, yet its impact on sensitive fauna remains unclear. We tracked 10 harbour porpoises for 5–10 days to determine exposure and behavioural reactions to modelled broadband noise (10 Hz–20 kHz, VHF-weighted) from individual ships monitored by AIS. Porpoises spent a third of their time experiencing ship noise above ambient, to which they regularly reacted by moving away during daytime and diving deeper during night. However, even ships >2 km away (noise levels of 93 ± 14 dB re 1 μPa2) caused animals to react 5–9 % of the time (∼18.6 ships/day). Ships can thus influence the behaviour and habitat use of cetaceans over long distances, with worrying implications for fitness in coastal areas where anthropogenic noise from dense ship traffic repeatedly disrupt their natural behaviour. • Noise from globally increasing ship traffic may disturb sensitive marine species. • We study exposure and reactions of GPS-tagged harbor porpoises to modeled broadband noise (10 Hz–20 kHz) from ships. • Individuals experienced modeled noise > ambient a third of their time. • Behavioral reactions (moving away or diving deeper) occurred 5–10% of the time even at longer distances (> 2 km). • Negative impacts on energy intake and fitness may accumulate over time in areas with intense ship traffic. [ABSTRACT FROM AUTHOR]

Abstract: Echolocation behaviour of a harbor porpoise and six finless porpoises was recorded in open-water systems using acoustic data loggers (A-tag). In total 1359 click trains were recorded during 4.6h for the harbor porpoise and 46,240 click trains were recorded during 82.3h for the finless porpoises. The harbor and finless porpoises produced sonar click trains every 12.3 and 6.4s on average, respectively. During the inter-click-train interval, the porpoises were silent or produced clicks below 148dB re. , the detection threshold of the tag. Ninety percent of the inter-click-train intervals were 20s or less in both species. This means that porpoises frequently produce intense click trains. Click-train intervals lasting over 50s constituted 1% of the total intervals in finless porpoises and 4% in the harbor porpoise. Both species swam without intense clicks for less than 10m in most cases, but occasionally remained silent or used undetected low-intensity clicks for more than 1min. During these periods, the porpoises would be susceptible to entanglement in fishing nets. [Copyright &y& Elsevier]

• The model presented by Kiełpińska and Kowalski (2021) rests on flawed assumptions. • The presented modelling of Kiełpińska and Kowalski (2021) is intransparent. • Kiełpińska and Kowalski (2021) do not review or consider relevant ecological data and hypotheses. In a recent paper in Ecological Indicators , Kiełpińska and Kowalski (K&K) present a model aimed to facilitate culling of a large fraction of the Baltic grey seal population without sacrificing management aims with regard to distribution. Their paper and model include several flawed assumptions with regard to grey seal biology, particularly life history, population structure and movements. The actual modelling exercise is intransparent and there is no discussion or account for uncertainties or ecological complexities. K&K do not mention or review the existing literature on the outcomes of marine mammal culls or investigations of the role of grey seals in the Baltic Sea ecosystem, but state an imperative that aquatic top predators must be controlled. Ecosystem modelling has indicated that fisheries and a large grey seal population can coexist and that culling of marine top predators can have unpredictable and unintended effects. Given the flawed assumptions, lack of regard for uncertainty and complexity as well as the actual knowledge gaps, we suggest great caution in the use of K&K's model. [ABSTRACT FROM AUTHOR]

There is an increasing need for comprehensive oceanographic sampling, and taking advantage of marine mammal studies of movements and habitat use for augmenting spatial and temporal coverage, especially in remote and inaccessible areas, is an attractive approach. Oceanographic sampling instruments that transmit profiles of temperature and salinity (CTD) via satellite were deployed on bowhead whales Balaena mysticetus. A novel satellite-linked CTD tag (WC) was compared to an established design (SMRU). The two types of tags were deployed equally on nine bowhead whales in West Greenland. Both tag types used Argos for relaying data and locations, while the WC tag also provided Fastloc-GPS for more accurate locations. One whale carried both tag types. When comparing the two tag types deployed on the same whale, more complete data were obtained from the WC tag in terms of number of profiles, locations and transmissions received, although placement of the tag on the back of the whale and antenna position may have affected some of these parameters. Why transmissions terminated is difficult to determine, however, physical loss of the tag from the whale and mechanical damage to the antenna are the most likely; none of the tags failed because of battery exhaustion. Although, differences in performance of the two tag types were found, we conclude that both satellite-linked CTD tag types deployed on large cetaceans can provide high resolution oceanographic profiles at times and in areas where traditional methods for collecting oceanographic data are logistically difficult and prohibitively expensive. • Bowhead whales in west Greenland as real-time autonomous sampling platforms. • Salinity, temperature, depths and position sampled by two CTD satellite tags types. • The tags provided data for up to 155 days. • When placed on the same whale, performance was generally better for one tag type. • An ecological understanding help to learn how bowhead whales respond to rising temp. [ABSTRACT FROM AUTHOR]

• Blood values of wild harbor porpoises compared with permanently kept indiviudals. • Season, sex, age and origin influenced the haematology and blood chemistry values. • Seasonality and the animal's physiological state are important to blood analysis. • Blood values are important baselines for environmental health indicators. Harbour porpoises (Phocoena phocoena) in the Baltic Sea are under increasing pressure from anthropogenic activities, which affect the overall health of populations. Individuals' haematologic and biochemistry parameters are known to be linked to a population's health status and are therefore useful tools for cross-population comparisons and to assess health patterns of a population through time. However, it is often difficult to acquire data representing the full range of values and assess the influence of intrinsic and extrinsic factors. Here, we present the range of haematology and blood chemistry values obtained from 46 wild (n = 54 blood samples) individuals incidentally caught in pound-nets and five porpoises in long-term human care (n = 449 blood samples) from an outdoor semi-open facility in Denmark. Although it was not possible to formally test the differences between samples from free-ranging and captive individuals, lymphocyte values were lower for free-ranging animals whereas eosinophils and white blood cell values were higher in captive individuals. Aspartate aminotransferase and alanin aminotransferase values were also lower for captive individuals compared to free-ranging ones. Age group did not influence any of the blood parameters tested for free-ranging individuals. Sodium values were higher for males compared to females. Values were higher and lower in the fall for platelets and lactic acid dehydrogenase, respectively, compared to the other seasons. Based on samples yielded by individuals in long-term human care, haemoglobin, mean cell volume, white blood cells, absolute lymphocyte count, and alkaline phosphatase values were all influenced by health status based on clinical examination. These are therefore candidate parameters to assess health status of wild porpoises. Our results underline that it is essential to obtain ranges of reference values for all haematologic and biochemistry markers in order to assess health status of free-ranging individuals. Individuals in human care provide the opportunity to observe biological and ecological determinates (e.g. age, season) of long-term biomarker response patterns and to assess the suite of biomarkers best suited to predict individual health status. [ABSTRACT FROM AUTHOR]

Abstract Knowledge on spatial and seasonal distribution of species is crucial when designing protected areas and implementing management actions. The Baltic Proper harbour porpoise (Phocoena phocoena) population is critically endangered, and its distribution is virtually unknown. Here, we used passive acoustic monitoring and species distribution models to describe the spatial and seasonal distribution of harbour porpoises in the Baltic Proper. Porpoise click detectors were deployed over a systematic grid of 297 stations in eight countries from April 2011 through July 2013. Generalized additive models were used to describe the monthly probability of detecting porpoise clicks as a function of spatially-referenced covariates and time. During the reproductive season, two main areas of high probability of porpoise detection were identified. One of those areas, situated on and around the offshore banks in the Baltic Proper, is clearly separated from the known distribution range of the Belt Sea population during breeding season, suggesting this is an important breeding ground for the Baltic Proper population. We commend the designation of this area as a marine protected area and recommend Baltic Sea countries to also protect areas in the southern Baltic Sea and the Hanö Bight where additional important harbour porpoise habitats were identified. Further conservation measures should be carried out based on analyses of overlap between harbour porpoise distribution and potentially harmful anthropogenic activities. Our study shows that large-scale systematic monitoring using novel techniques can give important insights on the distribution of low-density populations, and that international cooperation is pivotal when studying transnationally migratory species. Highlights • Results support the existence of a separate Baltic Proper porpoise population. • An important breeding site for the endangered Baltic Proper porpoise is identified. • Population distribution patterns give a solid base for designating protected areas. • Large-scale monitoring can give insights on distribution of low-density populations. • International cooperation is key for studies of transnationally migratory species. [ABSTRACT FROM AUTHOR]

Highlights: [•] We model impacts of disturbances on porpoise movement and population dynamics. [•] We assess the impact of by-catch and noise from wind turbines and ships. [•] The impact of noise was minor, but depended on the food replenishment rate. [•] The studied scenarios had no effect on the survival of the population. [•] This is the first study using a behaviour-based management model for marine mammals. [Copyright &y& Elsevier]

Abstract: Spatial trends of concentrations of perfluorinated chemicals (PFCs) were investigated in harbour seal liver tissue from seven locations in Denmark, ranging from the Wadden Sea in the southern North Sea to the Western Baltic. All samples were collected during the phocine distemper epizootic in 2002 which provided access to a large number of comparable samples over a short time period. PFOS was dominating (mean: 92% of ∑PFC) among the PFCs in the samples, followed by considerably lower concentrations of PFHxS (1.8%), PFDA (1.7%), PFNA (1.6%) PFUnA (1.5%), PFOA (0.9%) and PFOSA (0.5%). The concentrations of all the investigated compounds showed significant differences among the seven locations. PFOS showed the highest concentrations in the Wadden Sea, where high burdens have also been recorded in German seals. Most compounds showed a trend towards higher concentrations at one or both extremes of the geographic range. Two different patterns of relative PFC concentrations were detected; one in the inner Danish waters where PFOSA and PFUnA were more prevalent and another in the Wadden Sea and Limfjord where PFOA, PFHxS and PFNA were found in greater proportions. These patterns probably represent Baltic and North Sea contamination sources. [Copyright &y& Elsevier]

Abstract: Determining the movement of marine animals is logistically difficult and is currently primarily based on VHF and satellite-tracking telemetry, GPS, acoustic telemetry, and geolocation, all of which have substantial limitations in accurately locating the fine-scale movements of these animals. A recent development—that of dead-reckoning—is being increasingly used to examine the fine-scale movement of animals underwater. The advantages and drawbacks of this approach are quite different to those incurred by the other methods. This paper considers the advances that dead-reckoning can bring to the study of the often cryptic movement and behaviour of marine animals at sea. Methods used in determining position via dead-reckoning are presented and consideration is given to results derived from the use of dead-reckoning on cetaceans, pinnipeds, penguins and sea turtles; these are complemented by data on cormorants and albatrosses acquired using GPS systems. Suggestions are made as to how movement data derived from these devices can be analysed using indices that allow interpretation over a large variety of temporal and spatial scales. [Copyright &y& Elsevier]