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With a current global estimation of 600–700 individuals, Monachus monachus is considered among the most threatened seal species globally and is ranked as "Endangered" by the IUCN Red List of Threatened Species. The Mediterranean distribution of the species is fragmented, and the largest known sub-population inhabits its easternmost areas. The present study analyses the occurrence of M. monachus on Samos Island, in the north-eastern Aegean Sea, Greece. From May 2017 to November 2019, data were collected through a combination of monitoring approaches, including visual monitoring from a land position, opportunistic sightings collected by citizen science, and data of stranded individuals. Results indicate the constant occurrence of monk seals in the waters and coastal areas of Samos Island, confirming the importance of this area for conservation purposes. Furthermore, the results show that an integrated methodological approach can contribute to enhancing and increasing data collection, representing an effective method for conservation studies. This approach could be applied in other locations, allowing the scientific community to identify regions of interest, where to expand targeted monitoring and apply conservation measures. [ABSTRACT FROM AUTHOR]

The fossil remains of a seal of the genus Pachyphoca from the Upper Miocene Sarmatian stratum of the Morskaya-3 site (Neklinovskii district, Rostov region) were described. According to the structure of the humerus and pelvic bones, the seal was identified as Pachyphocaukrainica Koretsky et Rahmat, 2013. This is the first evidence of the presence of representatives of this genus in northeast of Taganrog Bay, demonstrating the similar composition of the Middle Sarmatian fauna of marine mammals in the western and eastern districts of the Northern Black Sea region. [ABSTRACT FROM AUTHOR]

An 88.5 cm long, 12.9 kg, 3-week-old stranded male Atlantic harbour seal (Phoca vitulina concolor) presented with cerebellar ataxia, delayed postural reactions, hyperaesthesia and nystagmus. The skull was enlarged and domed. Ultrasound through a persistent fontanelle in the frontal bone revealed hydrocephalus. Magnetic resonance imaging showed diffuse enlargement of the ventricular system, an absent cerebellar vermis, hypertrophy of the choroid plexus of the fourth ventricle and enlargement of the caudal fossa. Throughout rehabilitation, the seal failed to achieve milestones critical for successful release or placement in a managed care facility, including the ability to feed independently and haul out. Three months into rehabilitation it began to regurgitate and staff had difficulty administering food to the seal. The seal was euthanized due to a poor prognosis. Post-mortem examination confirmed a) aplasia of the dorsal cerebellar vermis and hypoplasia of the most dorsal portions of the right and left cerebellar hemispheres, b) severe, diffuse, congenital communicating hydrocephalus, and c) aplasia of the interthalamic adhesion and corpus callosum. This case represents the first report of Dandy–Walker-like malformation (DWLM) in a marine mammal and illustrates the importance of advanced imaging and thorough post-mortem examination in free-ranging pinnipeds that strand with evidence of neurological disease. [ABSTRACT FROM AUTHOR]

Ecological diversity has been reported for killer whales (Orcinus orca) throughout the North Atlantic but patterns of prey specialization have remained poorly understood. We quantify interindividual dietary variations in killer whales (n = 38) sampled throughout the year in 2017–2018 in northern Norway using stable isotopic nitrogen (δ15N: 15N/14N) and carbon (δ13C: 13C/12C) ratios. A Gaussian mixture model assigned sampled individuals to three differentiated clusters, characterized by disparate nonoverlapping isotopic niches, that were consistent with predatory field observations: seal‐eaters, herring‐eaters, and lumpfish‐eaters. Seal‐eaters showed higher δ15N values (mean ± SD: 12.6 ± 0.3‰, range = 12.3–13.2‰, n = 10) compared to herring‐eaters (mean ± SD: 11.7 ± 0.2‰, range = 11.4–11.9‰, n = 19) and lumpfish‐eaters (mean ± SD: 11.6 ± 0.2‰, range = 11.3–11.9, n = 9). Elevated δ15N values for seal‐eaters, regardless of sampling season, confirmed feeding at high trophic levels throughout the year. However, a wide isotopic niche and low measured δ15N values in the seal‐eaters, compared to that of whales that would eat solely seals (δN‐measured = 12.6 vs. δN‐expected = 15.5), indicated a diverse diet that includes both fish and mammal prey. A narrow niche for killer whales sampled at herring and lumpfish seasonal grounds supported seasonal prey specialization reflective of local peaks in prey abundance for the two fish‐eating groups. Our results, thus, show differences in prey specialization within this killer whale population in Norway and that the episodic observations of killer whales feeding on prey other than fish are a consistent behavior, as reflected in different isotopic niches between seal and fish‐eating individuals. [ABSTRACT FROM AUTHOR]

Polychlorinated biphenyls (PCBs) are recognised reproductive and immune system toxicants in marine mammals mediated by endocrine-disrupting mechanisms. As with other predators, seals are exposed to elevated bioaccumulated concentrations of PCBs and other persistent organic pollutants (POPs). Cryopreserved plasma samples from adult ringed (Phoca hispida; n = 39) and grey (Halichoerus grypus; n = 38) seals, sampled between 1998 and 2002 from Baltic Sea, Svalbard, and Sable Island (Canada) were used to investigate relationships between PCB exposure and sex hormone concentrations (progesterone; P4, 17α-hydroxy progesterone; 17α-OH-P4, testosterone; T4, 17β-estradiol; E2, estrone; E3). Immunoassay methods were used for quantification of analytes due to the limited sample volumes available. PCB concentrations were found to be significantly higher in Baltic seals than other sampling locations and were classed as "Exposed" seals while Svalbard and Sable Is seal were classed "Reference" seals (sexes and species separate). Mean hormone concentrations in Exposed seal were lower than Reference seals, and this was statistically significantly for 17α-OH-P4 (both sexes and both species), E2 (ringed and grey seal females), and E3 (grey seal females). Regression analyses (PCB v hormone concentrations) for each sex and species revealed significant correlations for P4 (Sable Is. female grey seals and female ringed seals), 17α-OH-P4 (Sable Is. male grey seals and Svalbard male ringed seals), T4 (Svalbard male ringed seals), E2 (female ringed seals), and E3 (female ringed seals and Baltic female grey seals). Although significant correlations are not evidence of cause and effect, the potential impact of hormone changes on endocrine homeostasis and reproductive health for seal populations warrants further investigation given that PCB concentrations found here are in the same range as those currently reported in seals from these populations. [ABSTRACT FROM AUTHOR]

Antarctic krill (Euphausia superba) is a key resource in the Antarctic region, as it is the primary food source for fish, whales, seals, flying birds, penguins and cephalopods. The high concentrations of the species and its possible uses -food for human and animal consumption and in the production of industrial, pharmaceutical and dietetic products-generates interest in the fishing industry. Its relevance motivated the implementation of administrative measures and international regulations for this fishery, which are summarized in this review. Chile is the only South American fishing country that has shown interest in participating in Antarctic krill fishery. Thus, between 1983 and 1994, the Fisheries Development Institute and some companies carried out fishing activities mainly aimed at prospecting and researching this species. However, starting in 2011, the factory trawler FV Betanzos began sustained commercial krill fishing aimed at krill meal production. This document analyzes the information collected by said vessel between 2011 and 2016, including areas of operation, fishing depth catches and CPUE obtained. Also, the main challenges faced by this fishery and the actions planned as solutions are assessed. [ABSTRACT FROM AUTHOR]

Peptidylarginine deiminases (PADs) are phylogenetically conserved calcium-dependent enzymes which post-translationally convert arginine into citrulline in target proteins in an irreversible manner, leading to functional and structural changes in target proteins. Protein deimination can cause the generation of neo-epitopes, affect gene regulation and also allow for protein moonlighting and therefore facilitate multifaceted functions of the same protein. PADs are furthermore a key regulator of cellular release of extracellular vesicle (EVs), which are found in most body fluids and participate in cellular communication via transfer of cargo proteins and genetic material. In this study, post-translationally deiminated proteins and EVs were assessed in sera of two seal species, grey seal and harbour seal. We report a poly-dispersed population of serum-EVs, which were positive for phylogenetically conserved EV-specific markers and characterised by transmission electron microscopy. A number of deiminated proteins critical for immune and metabolic functions were identified in the seal sera and varied somewhat between the two species under study, while some targets were in common. EV profiles of the seal sera further revealed that key microRNAs for inflammation, immunity and hypoxia also vary between the two species. Protein deimination and EVs profiles may be useful biomarkers for assessing health status of sea mammals, which face environmental challenges, including opportunistic infection, pollution and shifting habitat due to global warming. Image 1 • Key immune and metabolic proteins were identified as deiminated in seal sera. • EV serum profiles varied somewhat between seal species. • EV microRNA cargo varied between seal species for inflammatory related miR155, miR21 and hypoxia related miR210. • EV profiles and deiminated proteins are novel biomarkers in seal sera. [ABSTRACT FROM AUTHOR]

The present study describes a finding of the demodecid mite Demodex phocidi in the seal Phoca vitulina in the Baltic Sea. This is the first identification in Europe and the second in the world. This is also the first observation of the Demodecidae family in the pinnipeds outside North America. A high density of demodecid mites was observed in the skin of the examined seal, but no symptoms of parasitosis were observed. Our findings also supplement the taxonomic description and morphometry of D. phocidi. [ABSTRACT FROM AUTHOR]

In psychophysical studies of noise-induced hearing loss with marine mammals, exposure conditions are often titrated from levels of no effect to those that induce significant but recoverable loss of auditory sensitivity [temporary threshold shift (TTS)]. To examine TTS from mid-frequency noise, a harbor seal was exposed to a 4.1-kHz underwater tone that was incrementally increased in sound pressure level (SPL) and duration. The seal's hearing was evaluated at the exposure frequency and one-half octave higher (5.8 kHz) to identify the noise parameters associated with TTS onset. No reliable TTS was measured with increasing sound exposure level until the second exposure to a 60-s fatiguing tone of 181 dB re 1 μPa SPL (sound exposure level 199 dB re 1 μPa2s), after which an unexpectedly large threshold shift (>47 dB) was observed. While hearing at 4.1 kHz recovered within 48 h, there was a permanent threshold shift of at least 8 dB at 5.8 kHz. This hearing loss was evident for more than ten years. Furthermore, a residual threshold shift of 11 dB was detected one octave above the tonal exposure, at 8.2 kHz. This hearing loss persisted for more than two years prior to full recovery. [ABSTRACT FROM AUTHOR]

Some anthropogenic activities pose acute risks for marine species. For example, pile driving could damage the hearing of marine mammals while underwater explosions can also result in physical damage or death. Effective mitigation is required to reduce these risks, but the exclusion zones specified in regulations can extend over hundreds or thousands of metres and seals pose particular problems because they are difficult to detect at sea.Aversive sound mitigation aims to exclude animals from high‐risk areas before dangerous activities take place by broadcasting specific acoustic signals. Field research is needed to identify signals that might be effective in eliciting short‐term avoidance by marine species such as harbour seals (Phoca vitulina). A series of controlled‐exposure experiments (CEEs) were undertaken to measure seal movements in response to acoustic deterrent devices (ADD) and predator calls, and to assess the effectiveness of candidate signals for aversive sound mitigation.Seals were fitted with UHF/GPS transmitters providing continuous high‐resolution tracks and real‐time transmissions of their locations. A tracking/playback vessel located seals at sea and transmitted either ADD signals or orca (Orcinus orca) calls over a range of distances while seals were foraging or moving between sites. Behaviour before, during and after exposure was analysed to assess responses.One‐hundred and ten CEEs were assessed as being of at least 'adequate' quality. Of the 71 adequate trials with the Lofitech ADD, all 38 at ranges of <1 km (predicted received level 134.6 dB RMS re 1 μPa) elicited a response. The maximum response range was 3123 m (predicted RL: 111 dB RMS re 1 μPa). However, the responses observed did not always result in substantial movements away from the source, especially for seals that were travelling at the time of the exposures. More work is needed to better understand how exposure risks would be reduced in different scenarios.The mean net speed of horizontal movements for seals responding to aversive sounds (1.15 m s−1) was only 7% higher than their mean travel speed.Responses to broadcasts of orca calls were highly variable.The results suggest that signals similar to those generated by a Lofitech ADD could be used to reduce risks to harbour seals from pile driving and underwater explosions in coastal waters. More work will be needed to develop systems that match the requirements of industry and regulators and to explore whether these results can be generalized to offshore waters and to other phocids. [ABSTRACT FROM AUTHOR]

Anthropogenic micro debris in the marine environment is a growing concern worldwide, affecting multiple trophic levels, from primary consumers such as zooplankton, to meso- and apex predators like marine mammals and marine birds. In 2016–2017, during the processing of harbor seal (Phoca vitulina vitulina) and gray seal (Halichoerus grypus atlantica) fecal samples for fish otoliths and organic hard parts as part of a prey study, anthropogenic micro debris (>500 μm) was detected in 6% (n = 2/32) of harbor seal and 1% (n = 2/129) of gray seal samples. Spectral analysis identified the fragments as cellophane, alkyd resin and poly(ethylene:propylene:diene) (EPDM) rubber. These results show the potential indirect ingestion of micro debris, which can impact the health and welfare of marine wildlife. This is the first report of micro debris presence in wild populations of phocid seals for the northwestern Atlantic. • Discovery of man-made micro debris (>500 μm) in harbor and gray seal fecal samples • Evidence that in-depth microplastic studies are needed on NW Atlantic seal species • Microplastic composition: cellophane, alkyd resin and EPDM rubber [ABSTRACT FROM AUTHOR]

Prey switching is a phenomenon in which a predator disproportionately consumes the most abundant prey type, and switches to preferentially consume another prey type if the first becomes relatively rare. This concept may be expanded outside of its usual usage describing switching between prey species (interspecific), to describe switching between prey stages within a given species (intraspecific). Polar bears (Ursus maritimus) are thought to seek out naive ringed seal (Pusa hispida) pups in the spring, but how that may change in years with low seal productivity is unknown. We addressed two main questions: If polar bears typically select for ringed seals' pups, how does this change in years with reduced ringed-seal productivity? How does polar bear predation during years with low ringed-seal productivity impact the ringed seal population? We created a matrix population model for ringed seals to get an estimate of each stage's availability to polar bears in the spring. These estimates of availability were combined with existing studies on the ages of seals consumed by polar bears in years of both high and low ringed seal productivity. Our results suggest that polar bears typically strongly select for ringed seal pups, but switch to disproportionately select older ringed seals in years with low pup availability. The effects of this on ringed seal population growth appear negligible. Non-intuitive results on the effect of prey switching on the prey population emphasize the importance of considering environmental sequences rather than individual years. [ABSTRACT FROM AUTHOR]

Abstract Vessel slowdown may be an alternative mitigation option in regions where re-routing shipping corridors to avoid important marine mammal habitat is not possible. We investigated the potential relief in masking in marine mammals and fish from a 10 knot speed reduction of container and cruise ships. The mitigation effect from slower vessels was not equal between ambient sound conditions, species or vessel-type. Under quiet ambient conditions, a speed reduction from 25 to 15 knots resulted in smaller listening space reductions by 16–23%, 10–18%, 1–2%, 5–8% and 8% respectively for belugas, bowheads, bearded seals, ringed seals, and fish, depending on vessel-type. However, under noisy conditions, those savings were between 9 and 19% more, depending on the species. This was due to the differences in species' hearing sensitivities and the low ambient sound levels measured in the study region. Vessel slowdown could be an effective mitigation strategy for reducing masking. Graphical abstract Unlabelled Image Highlights • The relief in masking from a 10 knot vessel speed reduction was investigated. • Listening space was reduced most for seals, then whales and fish near the vessel. • Slowing vessels by 10 knots gave the most masking relief under noisy conditions. • Variance in masking relief was due to frequency-dependent hearing between species. • Vessel slowdown could be a viable mitigation option when re-routing cannot be done. [ABSTRACT FROM AUTHOR]

The article presents the study which examined frst extralimital record of an Eastern Pacific harbor seal pup and their offsprings at Guadalupe Island, Mexico. Details on the method of the study, which involved observation of the body condition and estimation of the length of the body of the seal pup, are offered.

The spatiotemporal distribution of harp seal pups around breeding grounds in the White Sea is considered. It is shown that spatial localization of groups of females with different terms of mass pup birth takes place. This somewhat confirms the data on the gregarious structure of White Sea harp seal population. It is possible to explain the structure of this adaptation of the seal population to different living conditions in different feeding areas. [ABSTRACT FROM AUTHOR]

The first year of life is typically the most critical to a pinniped’s survival, especially for Arctic phocids which are weaned at only a few weeks of age and left to locate and capture prey on their own. Their seasonal movements and habitat selection are therefore important factors in their survival. During a cooperative effort between scientists and subsistence hunters in October 2004, 2005, and 2006, 13 female and 13 male young (i.e., age <2) bearded seals (Erignathus barbatus) were tagged with satellite-linked dive recorders (SDRs) in Kotzebue Sound, Alaska. Shortly after being released, most seals moved south with the advancing sea-ice through the Bering Strait and into the Bering Sea where they spent the winter and early spring. The SDRs of 17 (8 female and 9 male) seals provided frequent high-quality positions in the Bering Sea; their data were used in our analysis. To investigate habitat selection, we simulated 20 tracks per seal by randomly selecting from the pooled distributions of the absolute bearings and swim speeds of the tagged seals. For each point in the observed and simulated tracks, we obtained the depth, sea-ice concentration, and the distances to sea-ice, open water, the shelf break and coastline. Using logistic regression with a stepwise model selection procedure, we compared the simulated tracks to those of the tagged seals and obtained a model for describing habitat selection. The regression coefficients indicated that the bearded seals in our study selected locations near the ice edge. In contrast, aerial surveys of the bearded seal population, predominantly composed of adults, indicated higher abundances in areas farther north and in heavier pack ice. We hypothesize that this discrepancy is the result of behavioral differences related to age. Ice concentration was also shown to be a statistically significant variable in our model. All else being equal, areas of higher ice concentration are selected for up to about 80%. The effects of sex and bathymetry were not statistically significant. The close association of young bearded seals to the ice edge in the Bering Sea is important given the likely effects of climate warming on the extent of sea-ice and subsequent changes in ice edge habitat. [ABSTRACT FROM AUTHOR]

Gray seals (Halichoerus grypus) have been rapidly recolonizing the Northeast US coast, eliciting concern from the fishing industry. However, the ecological effect of this recovery is still unknown and as such, research is needed to better understand how the diet composition of gray seals in US waters will contribute to the ecological impact. While previous research on seal diets has focused on the analysis of hard prey remains, stable isotope analysis presents an alternative method that can be used to describe marine mammal diets when direct observation is impossible. To address this issue, we used stable isotope analysis of gray seal pup vibrissae and lanugo from Monomoy Island, Cape Cod, MA during the 2015/2016 winter breeding season to estimate adult female diet composition during pregnancy. Stable isotope mixing models (SIMM) suggested adult female gray seals were consuming greater amounts of cephalopod prey and less sand lance than previously indicated from analysis of hard prey remains. However, using SIMMs to estimate the diet composition of gray seals remains difficult due to the large number of isotopically similar prey species and uncertainty in tissue-specific, stable isotope trophic enrichment factors. Even so, by combining prey sources into ecologically informative groups and integrating prior information into SIMMs it is possible to obtain additional insights into the diet of this generalist predator. [ABSTRACT FROM AUTHOR]

In this study, we used relatively large number of samples (n = 178) and control region of mtDNA (454bp) to clearify the divergence history of Japanese harbour seals (Phoca vitulina stejnegeri) and phylogenetic relationship between the seals in Japan and other countries. Our results suggested that Japanese harbour seals possibly consisted of more than two lineages and secondary contact of populations after a long isolation. Furthermore, one of the lineage was made only by Japanese harbour seals (Group P1). The proportion of Group P1 was the highest at the South West and gradually decreased towards the North East of Hokkaido, Japan. On the other hand, the haplotypes do not belonged to Group P1 showed close relationship to the seals in the North Pacific. Based on the fossil record of harbour seal in Japan and the range of sea ice during the Last Glacial Maximum (LGM), Group P1 might have entered Japan before the LGM and became isolated due to the geographical boundary, and gradually extended its range from the South West towards the North East of Hokkaido after the disappearance of the sea ice, while the seals which are not in Group P1 immigrated into Japan from the North Pacific. [ABSTRACT FROM AUTHOR]

Selection of breeding location can influence reproductive success and fitness. Breeding dispersal links habitat use and reproduction. This study investigated factors affecting breeding dispersal and its reproductive consequences in grey seals ( Halichoerus grypus) on Sable Island, Nova Scotia. Breeding dispersal distance was determined in 692 individually marked, known-age female grey seals observed from 2004 to 2014. We used generalized linear mixed-effects models to test hypotheses concerning environmental and demographic factors influencing breeding dispersal distance and the consequences of dispersal distance on offspring weaning mass. Grey seal females rarely exhibited fidelity to previous breeding sites. Median dispersal distance between years was 5.1 km. Only 2.9% of females returned to a previous breeding site. Breeding dispersal distance was affected by parity and density, but effects were small and are presumably of no biological significance. Variation in dispersal distance among adult females was large. Dispersal distance had no significant influence on offspring weaning mass; however, as previously found, pup sex and maternal age did. Although breeding location was not important, heavier pups were born in habitats with no tidal or storm-surge influence indicating that breeding habitat type did influence offspring size at weaning. The lack of site fidelity in grey seals on Sable Island is associated with an unpredictable and changing landscape (sand dunes) that could make it difficult for females to locate previous breeding locations. Although breeding location within habitat type had small consequences on offspring weaning mass, we detected no evidence that breeding site selection within the habitat had consequences to females. [ABSTRACT FROM AUTHOR]

Individual specialization ( IS), where individuals within populations irrespective of age, sex, and body size are either specialized or generalized in terms of resource use, has implications on ecological niches and food web structure. Niche size and degree of IS of near-top trophic-level marine predators have been little studied in polar regions or with latitude. We quantified the large-scale latitudinal variation of population- and individual-level niche size and IS in ringed seals ( Pusa hispida) and beluga whales ( Delphinapterus leucas) using stable carbon and nitrogen isotope analysis on 379 paired ringed seal liver and muscle samples and 124 paired beluga skin and muscle samples from eight locations ranging from the low to high Arctic. We characterized both within- and between-individual variation in predator niche size at each location as well as accounting for spatial differences in the isotopic ranges of potential prey. Total isotopic niche width ( TINW) for populations of ringed seals and beluga decreased with increasing latitude. Higher TINW values were associated with greater ecological opportunity (i.e., prey diversity) in the prey fish community which mainly consists of Capelin ( Mallotus villosus) and Sand lance ( Ammodytes sp.) at lower latitudes and Arctic cod ( Boreogadus saida) at high latitudes. In beluga, their dietary consistency between tissues also known as the within-individual component ( WIC) increased in a near 1:1 ratio with TINW (slope = 0.84), suggesting dietary generalization, whereas the slope (0.18) of WIC relative to TINW in ringed seals indicated a high degree of individual specialization in ringed seal populations with higher TINWs. Our findings highlight the differences in TINW and level of IS for ringed seals and beluga relative to latitude as a likely response to large-scale spatial variation in ecological opportunity, suggesting species-specific variation in dietary plasticity to spatial differences in prey resources and environmental conditions in a rapidly changing ecosystem. [ABSTRACT FROM AUTHOR]

Active acoustics as a tool to detect and avoid Arctic marine mammals was assessed in the Canadian Beaufort Sea. The target strengths and shape of the echoes of whales and seals were characterized using a bi-frequency (38 and 120 kHz) split-beam scientific echosounder in winter 2003/2004 and a scientific scanning sonar (20-30 kHz) in summer 2011. The echosounder detected 452 signals of diving ringed seals and the sonar detected 59 bowhead whales, 13 ringed seals, and 2 bearded seals. Target strengths of diving ringed seals tracked by the echosounder ranged from -56 to -12 dB re: 1 m² and did not vary with the depth of the animal. Target strengths of animals tracked by the sonar varied from -15 to 10 dB for bowhead whales and from -37 to -3 dB for seals. Marine mammals presented higher target strength values near broadside than near tail- or head-on. The sonar detected whales at a distance up to 2000 m and their echoes were discriminated from that of seals. This study suggests that active acoustic technology can be used as a complementary tool for marine mammal surveys in the Arctic. [ABSTRACT FROM AUTHOR]

Foraging by large (425 kg), mammalian carnivores often entails cryptic tactics to surreptitiously locate and overcome highly mobile prey. Many forms of intermittent locomotion from stroke-and-glide maneuvers by marine mammals to sneak-and-pounce behaviors by terrestrial canids, ursids, and felids are involved. While affording proximity to vigilant prey, these tactics are also associated with unique energetic costs and benefits to the predator. We examined the energetic consequences of intermittent locomotion in mammalian carnivores and assessed the role of these behaviors in overall foraging efficiency. Behaviorally-linked, three-axis accelerometers were calibrated to provide instantaneous locomotor behaviors and associated energetic costs for wild adult Weddell seals (Leptonychotes weddellii) diving beneath the Antarctic ice. The results were compared with previously published values for other marine and terrestrial carnivores. We found that intermittent locomotion in the form of extended glides, burst-and-glide swimming, and rollercoaster maneuvers while hunting silverfish (Pleuragramma antarcticum) resulted in a marked energetic savings for the diving seals relative to continuously stroking. The cost of a foraging dive by the seals decreased by 9.2–59.6%, depending on the proportion of time gliding. These energetic savings translated into exceptionally low transport costs during hunting (COTHUNT) for diving mammals. COTHUNT for Weddell seals was nearly six times lower than predicted for large terrestrial carnivores, and demonstrates the importance of turning off the propulsive machinery to facilitate cost-efficient foraging in highly active, air-breathing marine predators. [ABSTRACT FROM AUTHOR]

Ringed seals (Pusa hispida) are semi-aquatic marine mammals with a circumpolar Arctic distribution. In this study, we investigate the amphibious hearing capabilities of ringed seals to provide auditory profiles for this species across the full range of hearing. Using psychophysical methods with two trained ringed seals, detection thresholds for narrowband signals were measured under quiet, carefully controlled environmental conditions to generate aerial and underwater audiograms. Masked underwater thresholds were measured in the presence of octave-band noise to determine critical ratios. Results indicate that ringed seals possess hearing abilities comparable to those of spotted seals (Phoca largha) and harbor seals (Phoca vitulina), and considerably better than previously reported for ringed and harp seals. Best sensitivity was 49 dB re. 1 μPa (12.8 kHz) in water, and -12 dB re. 20 μPa (4.5 kHz) in air, rivaling the acute hearing abilities of some fully aquatic and terrestrial species in their respective media. Critical ratio measurements ranged from 14 dB at 0.1 kHz to 31 dB at 25.6 kHz, suggesting that ringed seals - like other true seals - can efficiently extract signals from background noise across a broad range of frequencies. The work described herein extends similar research on amphibious hearing in spotted seals recently published by the authors. These parallel studies enhance our knowledge of the auditory capabilities of ice-living seals, and inform effective management strategies for these and related species in a rapidly changing Arctic environment. [ABSTRACT FROM AUTHOR]

Northern fur seal Callorhinus ursinus numbers on the Pribilof Islands have been in decline over the past two decades while numbers have increased at other sites, such as in the Kuril Islands in Russia and at Bogoslof Island in the Aleutian Islands. Although these divergent abundance trends remain unexplained, the potential influence of food limitations could be studied by examining the time–energy budgets of individual lactating fur seals. Our goal was to find suitable proxies for food intake and energy expenditure of lactating seals so that we might provide time and energy budgets of an increasing population on Lovushki Island, Russia that could be compared with the declining Pribilof fur seal population. Between 2005 and 2008, we outfitted 13 lactating fur seals with instruments that collected data on depth, external temperature, stomach temperature, GPS location, and acceleration. With these data we investigated proxies for 1) food intake, including time spent at sea, time spent diving, vertical travel distance (VTD), wiggle behavior, and changes in stomach temperature; 2) involuntary costs, including indices of basal metabolism (BMCI), thermal exposure, and instrument hydrodynamic drag (TAG); and 3) locomotive costs, including overall dynamic body acceleration (ODBA), horizontal travel distance, and flipper strokes. We also considered an index of work (WORK) calculated using horizontal distance, ODBA, and seal mass. Multimodel inference was used to determine which proxies best described changes in seal mass at sea when considering two sets of candidate models that differed by excluding or including locomotive costs ( n = 13 and n = 7, respectively). Seal mass changes were positively associated with VTD and TAG and negatively associated with BMCI (p < 0.001, adjusted R 2 = 0.84) when locomotive proxies were excluded. With locomotive proxies considered, models were improved and mass changes were best described by being positively related to VTD and negatively associated with WORK (p < 0.001, adjusted R 2 = 0.95). We suggest that relative energy budgets for individual lactating northern fur seals could be compared using proxies for energetics that are easily monitored with standard data logging instruments. [ABSTRACT FROM AUTHOR]

Habitat preference maps are a way of representing animals' space use in two dimensions. For marine animals, the third dimension is an important aspect of spatial ecology. We used dive data from seven gray seals Halichoerus grypus (a primarily benthic forager) collected with GPS phone tags (Sea Mammal Research Unit) to investigate the distribution of the maximum depth visited in each dive. We modeled maximum dive depth as a function of spatiotemporal covariates using a generalized additive mixed model ( GAMM) with individual as a random effect. Bathymetry, horizontal displacement, latitude and longitude, Julian day, sediment type, and light conditions accounted for 37% of the variability in the data. Persistent patterns of autocorrelation in the raw data suggest that individual intrinsic rhythm might be an important factor, not captured by external covariates. The strength of using this statistical method to generate spatial predictions of the distribution of maximum dive depth is its applicability to other plunge and pursuit divers. Despite being predictions of a point estimate, these maps provide some insight into the third dimension of habitat use in marine animals. The capacity to predict this aspect of vertical habitat use may help avoid conflict between animal habitat and coastal or offshore developments. [ABSTRACT FROM AUTHOR]

Abstract: Harbour seals as top predators and indicators for ecosystem health are exposed to increasing pressure caused by anthropogenic activities in their marine environment. After their lactation period of about 24 days pups are weaned and left to hunt on their own. Little is known about the development of their immune system and a better understanding of anthropogenic impacts on the general health and immune system of harbour seal pups is needed. mRNA transcription of six immuno-relevant biomarkers was analysed in 13 abandoned harbour seal pups from the North Sea, fostered at the Seal Centre Friedrichskoog, Germany. RNAlater blood samples were taken at admission, day 22 and before release and analysed using RT-qPCR. Significant differences in HSP70, cytokine IL-2 and xenobiotic biomarkers AHR, ARNT and PPARα transcription were found between admission, during rehabilitation and before release. Highest levels at admission may result from dehydration, handling, transport and contaminant exposure via lactation. The significant decrease is linked to health improvement, feeding and adaptation. The increase before release is suspected to be due to infection pressure and contaminant exposure from feeding on fish. Molecular biomarkers are a sensitive tool to evaluate health and pollutant exposure and useful to serve as early warning indicators, monitoring and case-by-case tool for marine mammals in human care and the wild. [Copyright &y& Elsevier]

Given their coastal site fidelity and opportunistic foraging behavior, harbor seals ( Phoca vitulina) may serve as sentinels for coastal ecosystem health. Seals using urbanized coastal habitat can acquire enteric bacteria, including Vibrio that may affect their health. To understand Vibrio dynamics in seals, demographic and environmental factors were tested for predicting potentially virulent Vibrio in free-ranging and stranded Pacific harbor seals ( Phoca vitulina richardii) off California. Vibrio prevalence did not vary with season and was greater in free-ranging seals (29 %, n = 319) compared with stranded seals (17 %, n = 189). Of the factors tested, location, turbidity, and/or salinity best predicted Vibrio prevalence in free-ranging seals. The relationship of environmental factors with Vibrio prevalence differed by location and may be related to oceanographic or terrestrial contributions to water quality. Vibrio parahaemolyticus, Vibrio alginolyticus, and Vibrio cholerae were observed in seals, with V. cholerae found almost exclusively in stranded pups and yearlings. Additionally, virulence genes (trh and tdh) were detected in V. parahaemolyticus isolates. Vibrio cholerae isolates lacked targeted virulence genes, but were hemolytic. Three out of four stranded pups with V. parahaemolyticus (trh+ and/or tdh+) died in rehabilitation, but the role of Vibrio in causing mortality is unclear, and Vibrio expression of virulence genes should be investigated. Considering that humans share the environment and food resources with seals, potentially virulent Vibrio observed in seals also may be of concern to human health. [ABSTRACT FROM AUTHOR]

Summary: Pathological examination of stranded marine mammals provides information on the causes of mortality in their populations. Patterns of stranding and causes of death of dead-stranded seals on the Dutch coast were analyzed over a 30-year period (1979–2008). Stranding data (n =1,286) and post-mortem data (n =379) from common seals (Phoca vitulina) and grey seals (Halichoerus grypus) found dead, or that died before admission to rehabilitation, were obtained from the Seal Rehabilitation and Research Centre database. Data for the years 1988 and 2002, when mass mortality occurred due to phocine distemper virus epidemics, were excluded. Common seal stranding increased from one to nearly 100 per year over this period. This coincides with the increase in the number of common seals in Dutch waters over recent decades. Grey seal stranding increased gradually from one to about 40 per year over the period, reflecting recolonization of Dutch waters by this species. For both species, the trend in stranding of dead seals was found to be in line with that of seals observed in Dutch waters during aerial surveys and did not provide any indications of a relative change in the stranding rate of dead seals. The total monthly stranding rates peaked at more than 120 in June and July for common seals and at nearly 60 in January for grey seals. This coincides with the pupping periods of the two species. Besides phocine distemper, the most common causes of death in investigated common seals (n =286) were by-catch (confirmed and inferred) (19%), pup starvation (7%), intestinal volvulus (7%) and parasitic bronchopneumonia (6%). The most common causes of death in investigated grey seals (n =93) were by-catch (confirmed and inferred) (15%), pup starvation (11%) and trauma (5%). The relative occurrence of by-catch significantly decreased over time for grey seals, but not for common seals. Common seals were affected by infectious disease significantly more often than grey seals, mainly because of a higher occurrence of parasitic pneumonia. Phocine distemper caused mass mortalities among common seals, but not among grey seals. These findings in dead-stranded seals differ in part from those reported elsewhere in live-stranded seals, for which pup starvation and parasitic bronchopneumonia were the main causes of stranding. A substantial proportion of seals in Dutch waters die from causes related to human activity. Continued monitoring of stranding patterns and causes of death is warranted for early detection of changes and the possibility of taking timely management actions. [Copyright &y& Elsevier]

Understanding historical roles of species in ecosystems can be crucial for assessing long term human impacts on environments, providing context for management or restoration objectives, and making conservation evaluations of species status. In most cases limited historical abundance data impedes quantitative investigations, but harvested species may have long-term data accessible from hunting records. Here we make use of annual hunting records for Caspian seals (Pusa caspica) dating back to the mid-19th century, and current census data from aerial surveys, to reconstruct historical abundance using a hind-casting model. We estimate the minimum numbers of seals in 1867 to have been 1-1.6 million, but the population declined by at least 90% to around 100,000 individuals by 2005, primarily due to unsustainable hunting throughout the 20th century. This collapse is part of a broader picture of catastrophic ecological change in the Caspian over the 20th Century. Our results combined with fisheries data show that the current biomass of top predators in the Caspian is much reduced compared to historical conditions. The potential for the Caspian and other similar perturbed ecosystems to sustain natural resources of much greater biological and economic value than at present depends on the extent to which a number of anthropogenic impacts can be harnessed. [ABSTRACT FROM AUTHOR]

Sealpox, a zoonotic disease affecting pinnipeds (seals and sea lions), can occur among captive and convalescing animals. We surveyed 1 worker each from 11 marine mammal centers and interviewed 31 other marine mammal workers to ascertain their knowledge of and experience with sealpox virus and to identify factors associated with sealpox virus outbreaks among pinnipeds in marine rehabilitation facilities. Demographic and health data were obtained for 1,423 pinnipeds at the 11 facilities. Among the 23 animals in which sealpox was clinically diagnosed, 4 arrived at the facility ill, 11 became ill <5 weeks after arrival, and 2 became ill ≥5 weeks after arrival; the timing of illness onset was unknown for 6 animals. Most infections occurred in pinnipeds <1 year of age. Nine affected animals were malnourished; 4 had additional illnesses. Sealpox had also occurred among workers at 2 facilities. Sealpox is a noteworthy zoonosis of rehabilitating convalescing pinnipeds; workplace education can help to minimize risks for human infection. [ABSTRACT FROM AUTHOR]

Abstract: Ireland''s waters represent a valuable resource encompassing productive fishing grounds and important oil and gas reserves. As a species rich marine environment, Ireland''s waters are also an important habitat for many species of marine mammal. Specifically, grey seals (Halichoerus grypus) and harbour seals (Phoca vitulina) are widespread in Irish coastal waters and at least 24 species of cetacean have been reported at sea. The coastal zone represents critical habitat for many of these species, in particular seals that use both terrestrial and aquatic coastal habitat and are vulnerable to habitat degradation. Increasing exploitation of marine resources has increased their exposure to a range of anthropogenic effects including pollution and habitat loss. As top predators seals interact with commercial fisheries both directly and indirectly for resources and conflicts arise. The relatively recent move towards ‘greener’ resource exploitation such as marine renewable energy does not come without negative consequences for marine mammals including seals, which are afforded protection under national and international conservation legislation, highlighting the difficulties faced by resource managers. The sustainable exploitation of resources whilst conserving biodiversity is a challenging task and effective management implementation depends on appropriate policy informed by reliable scientific data. This paper outlines the conservation needs of seals in Irish waters, reviews our current knowledge of these species in Irish water, provides a critical analysis of the existing legislative framework and describes how research outputs can inform present and future policy decisions. [Copyright &y& Elsevier]

The article presents a study which performed sequence analysis and molecular characterization of parapoxvirus on nodular lesions in a Phoca Largha seal in Japan. The purpose was to clarify the genetic relationship between parapoxviruses in both pinnipeds and cetaceans in Japan and other countries. Deoxyribonucleic acid (DNA) was extracted from the lesions to detect orthopoxvirus and parapoxvirus DNA using the polymerase chain reaction (PCR) method. It showed how the partial nucleotide sequence of the envelope gene determined from the PCR product were closely related to 2 parapoxvirus strains from Alaskan spotted seals. Since virus-neutralizing (VN) antibody against canine distemper virus (CDV) was not detected, it concludes that the lesions were infections caused by pinniped parapoxvirus.

Infrared thermography was used to monitor the healing process at flipper tag sites in gray seal ( Halichoerus grypus) pups. We tested the hypothesis that tagging would result in a rise in surface temperature associated with tag site healing processes compared with adjacent untagged areas of the flipper. Prior to tagging thermal images were recorded of the dorsal side of hind flippers of pups tagged in early lactation ( n= 20) and at weaning ( n= 19) on the Isle of May, Scotland (56°11′N, 02°33′W) from October to December 2008. Pups tagged in early lactation were sampled again at late lactation, at weaning and then every 3 d for an average of 29 d post-tagging while pups tagged at weaning were sampled every 3 d for an average of 17 d post-tagging. Tag sites were also scored for signs of infection or swelling at each sampling. Results showed that (1) small temperature increases associated with wound healing processes around the tag site returned to pre-tagging levels before animals leave the island and (2) there was little evidence of tagging-related infections or tag loss irrespective of age at tagging. [ABSTRACT FROM AUTHOR]

Persistent organic pollutants (POPs) have been associated with adverse health effects in marine mammals. However, the complex mixtures to which free-ranging populations are exposed constrain the elucidation of cause-and-effect relationships between specific POPs and the observed health risks. In this study, we 1) assembled data from studies showing polychlorinated biphenyl (PCB)-associated effects on the health of free-ranging harbor seals in the northeastern Pacific Ocean, 2) carried out additional POP analyses on seal samples to broaden the available data on contaminant residues, and 3) derived estimates of individual POPs and their toxic risks. Taken together, these components were used to generate a new toxicity reference value (TRV) for the protection of marine mammal health. In this case study of seals in British Columbia, Canada, and Washington State, USA, PCBs were the single most abundant POP and were correlated with several adverse health effects. PCB exposures consistently exceeded regulatory toxicity thresholds for fish-eating wildlife. Nursing seal pups were at particular risk, reflecting their greatly increased dietary intake of PCBs and their sensitivity to developmental toxicity. Based on the collective evidence obtained, we propose TRVs (consisting of 5% tissue residue concentration and dose) of 1.3 mg/kg lipid weight tissue residue in blubber and 0.05 mg/kg lipid weight tolerable daily intake in prey. Insofar as the TRVs are lower than previously established TRVs and regulatory guidelines, our study highlights the current underestimation of risks associated with PCBs in high-trophic-level wildlife. Integr Environ Assess Manag 2010;6:631-640. © 2010 SETAC [ABSTRACT FROM AUTHOR]

Identifying factors affecting juvenile survival is important to understanding the dynamics of populations and may also provide insights into life history theory and the selective forces shaping evolution. Quantifying the relative influence of the various potential selective forces for the post-birth, maternal dependency, and independent periods is difficult and often limits investigators to estimating a single juvenile survival rate for the first year of life, or from birth to recruitment. We examined survival of individually marked Weddell seal Leptonychotes weddellii pups during the maternal dependency period in Erebus Bay, Antarctica from 2005–2007. We used mark-recapture models to evaluate competing a priori hypotheses regarding variation in daily pre-weaning survival rates (φ) during the first 42 days of age. The a priori model receiving the most support from the data supported several of our predictions: increased with pup age and was higher for pups born later in the season and to older mothers. Increases in with increasing pup age may have been due to improved resilience to the environment, phenotypic selection against the frailest pups, or both. Maternal age was more important to than was maternal experience or age of primiparity, potentially indicating that age-related increases in body mass allow greater offspring provisioning, or age-related improvements in competitive abilities benefit offspring during the period of maternal care. Depending on the timing of birth and the age of the mother, 42 days ranged from 0.79 (SE = 0.05) to 0.98 (SE = 0.01). These exceptionally high pre-weaning survival rates contrast with estimates from other large terrestrial and marine mammal species where neonate survival is considerably lower and suggest that in species with similar life histories, pre-weaning survival probability may be buffered from both predators and environmental fluctuations during the period of maternal nutritional dependency. Climatic changes affecting stability of ice used for pupping substrate or extent of fast-ice buffering pupping colonies from predators have the potential to reduce pre-weaning survival and may have important implications for population growth rates. [ABSTRACT FROM AUTHOR]

Abstract: A large scale, systematic, acoustic survey for whales and seals in eastern Antarctic waters was conducted in January-February 2006. During the BROKE-West survey of Southern Ocean waters between 30 and 80° E longitude, an acoustic survey was conducted to complement a traditional visual survey for marine mammal occurrence and distribution. As part of the survey, 145 DIFAR sonobuoys were deployed every 30’ of latitude on north-south transects, and prior to CTD stations on the initial east-west transect. Underwater sound was analyzed for 70 minute samples from each sonobuoy. Blue whales were the most commonly recorded species, identified at 55 of the sonobuoy deployment sites. Other species recorded include: sperm (46 sites), fin (14), humpback (2), and sei (3) whales, and leopard (11) and Ross (17) seals. Large numbers of blue and sperm whales, and all Ross seals were detected on the westernmost two transects, which were the only transects of the survey with relatively extensive sea ice remaining off the continental shelf. Large numbers of blue whales were also detected in the more eastern waters of the survey off the Prydz Bay region, while two detections of pygmy blue whales represent the farthest south these whales have been recorded. Of the relatively few fin whale detections, most occurred in more northerly waters. Fin whale vocalizations from this region were distinctly different than those recorded elsewhere around Antarctica suggesting acoustic recordings may be useful to delineate regional or stock boundaries of this species. Previously undescribed sounds were attributed to Ross seals. Acoustic detections of these and leopard seal sounds indicate these animals venture further from their traditionally described distributions, with vocalizing leopard seals occurring much further north than might be expected. Overall, the results of the sonobuoy survey provide a measure of each species’ relative spatial distribution over the survey area based on acoustic detections, and when combined with the results of the visual survey, will provide a comprehensive view of marine mammal distribution throughout the region during the BROKE-West survey. [Copyright &y& Elsevier]

Pinniped dietary information is crucial for understanding marine ecosystems; however, in the North Atlantic, grey and harbour seals haulout concomitantly and their faeces are visually indistinguishable. Therefore, we developed molecular methods to differentiate the species’ scat. PCR primers were created that amplify a portion of mitochondrial 16S ribosomal DNA in grey and harbour seals. The samples were amplified and the resulting products were digested using the restriction enzyme Tsp509I, producing diagnostic banding patterns. These tools provide a mechanism by which separate dietary analysis can be achieved for grey and harbour seals at mixed haulouts in New England. [ABSTRACT FROM AUTHOR]

Graham, I. M., Harris, R. N., Denny, B., Fowden, D., and Pullan, D. 2009. Testing the effectiveness of an acoustic deterrent device for excluding seals from Atlantic salmon rivers in Scotland. – ICES Journal of Marine Science, 66: 860–864. In Scotland, there is frequent conflict between salmon rod fisheries and seals, which is often managed by the shooting of seals in rivers, with potential negative impacts on protected populations of seals. Non-lethal devices have not been tested extensively in rivers as an alternative to shooting. Trials were carried out between January and May 2006 on the River North Esk and between October 2007 and February 2008 on the River Conon in northeast Scotland to examine the effectiveness of an acoustic deterrent device (ADD) at deterring seals from a specific area of river and as a barrier to the upstream movement of seals. The ADD was switched on and off alternately for periods of several days, and surveys were carried out to estimate the number of seals present within each river. The ADD had no significant effect on the absolute abundance of seals in the survey area in either river, but it did reduce seal movement upstream significantly, by ∼50% in both rivers. This reduction was constant over the 4-month period of both trials. The results suggest that ADDs might be a useful conservation tool in the management of seal–salmon conflicts, particularly in estuaries and rivers where the potential for adversely impacting cetaceans is limited. [ABSTRACT FROM PUBLISHER]

The Wadden Sea is an important habitat for harbour seals and grey seals. They regularly haul-out on sandbanks and islands along the coast. Comparably little is known about the time seals spend at sea and how they use the remainder of the North Sea. Yet, human activity in offshore waters is increasing and information on seal distribution in the North Sea is crucial for conservation and management. Aerial line transect surveys were conducted in the German bight from 2002 to 2007 to investigate the distribution and abundance of marine mammals. Distance sampling methodology was combined with density surface modelling for a spatially explicit analysis of seal distribution in the German North Sea. Depth and distance to coast were found to be relevant predictor variables for seal density. Density surface modelling allowed for a depiction of seal distribution in the study area as well as an abundance estimate. This is the first study to use aerial survey data to develop a density surface model (DSM) for a spatially explicit distribution estimate of seals at sea. [ABSTRACT FROM AUTHOR]

Abstract: Gastrointestinal lesions with uncertain etiology have been widely described among pinnipeds. The aim of our study was to investigate the presence of Helicobacter spp. in the gastric mucosa of South American fur seals (Arctocephalus australis). Gastric biopsies from thirteen seals, stranded on the shores of the Southwestern Atlantic Ocean in Argentina, were evaluated for the presence of Helicobacter spp. by PCR and DNA sequence analysis. Six gastric biopsies were positive for Helicobacter spp. Pairwise sequence comparisons showed less than 95% identity to novel Helicobacter spp. described from pinnipeds from North America and Australia. However, phylogenetic analysis revealed that the South American fur seal sequences clustered with 99–100% homology with H. cetorum, a species isolated from dolphins and whales. The presence of H. cetorum in pinnipeds, if confirmed by its isolation from the gastric mucosa of these mammals, demonstrates the wide host range of this bacterium in the marine environment. [Copyright &y& Elsevier]

Offshore orientation in marine mammals is still a mystery. For visual orientation during night-time foraging and travelling in the open seas, seals cannot rely on distant terrestrial landmarks, and thus might use celestial cues as repeatedly shown for nocturnally migrating birds. Although seals detect enough stars to probably allow for astronavigation, it was unclear whether they can orient by the night sky. The widely accepted cognitive mechanism for bird night-time orientation by celestial cues is a time-independent star compass with learned geometrical star configurations used to pinpoint north as the rotational centre of the starry sky while there is no conclusive evidence for a time-compensated star compass or true star navigation. Here, we present results for two harbour seals orienting in a custom made swimming planetarium. Both seals learned to highly accurately identify a lodestar out of a pseudo-randomly oriented, realistic projection of the northern hemisphere night sky. Providing the first evidence for star orientation capability in a marine mammal, our seals’ outstanding directional precision would allow them to steer by following lodestars of learned star courses, a celestial orientation mechanism that has been known to be used by Polynesian navigators but has not been considered for animals yet. [ABSTRACT FROM AUTHOR]

Adult salmonids returning to the River Tees (north-east England) tagged with temperature-sensing acoustic transmitters provided some unexpected and novel information on the possible impact of seal predation at a tidal barrage 16 km from the sea. Predation events of tagged fish by seals were inferred by an increase in the temperature transmitted by the acoustic tags. Subsequent events of feeding or drinking by the seals were also inferred from further changes in temperature recorded by tags whilst in their stomachs. Rates of inferred predation on tagged individuals were high (47%). This is the first time that temperature-sensing transmitters deployed inside wild salmonids have revealed instances of predation by, and subsequent feeding ecology of, marine mammals. The results are discussed in relation to the use of such technology in future studies attempting to address the interactions between marine mammals and their fish prey species. [ABSTRACT FROM AUTHOR]

Abstract: Weddell seals undergo lung collapse during dives below 50m depth. In order to explore the physiological mechanisms contributing to restoring lung volume and gas exchange after surfacing, we studied ventilatory parameters in three Weddell seals between dives from an isolated ice hole on McMurdo Sound, Antarctica. Methods: Lung volumes and CO2 elimination were investigated using a pneumotachograph, infrared gas analysis, and nitrogen washout. Thoracic circumference was determined with a strain gauge. Exhaled nitric oxide was measured using chemiluminescence. Results: Breathing of Weddell seals was characterized by an apneustic pattern with end-inspiratory pauses with functional residual capacity at the end of inspiration. Respiratory flow rate and tidal volume peaked within the first 3min after surfacing. Lung volume reductions before and increases after diving were approximately 20% of the lung volume at rest. Thoracic circumference changed by less than 2% during diving. The excess CO2 eliminated after dives correlated closely with the duration of the preceding dive. Nitric oxide was not present in the expired gas. Conclusion: Our data suggest that most of the changes in lung volume during diving result from compression and decompression of the gas remaining in the respiratory tract. Cranial shifts of the diaphragm and translocation of blood into the thorax rather than a reduction of thoracic circumference appear to compensate for lung collapse. The time to normalise gas exchange after surfacing was mainly determined by the accumulation of CO2 during the dive. These findings underline the remarkable adaptations of the Weddell seal for restoring lung volume and gas exchange after diving. [Copyright &y& Elsevier]

The earth's climate is changing, possibly at an unprecedented rate. Overall, the planet is warming, sea ice and glaciers are in retreat, sea level is rising, and pollutants are accumulating in the environment and within organisms. These clear physical changes undoubtedly affect marine ecosystems. Species dependent on sea ice, such as the polar bear (Ursus maritimus) and the ringed seal (Phoca hispida), provide the clearest examples of sensitivity to climate change. Responses of cetaceans to climate change are more difficult to discern, but in the eastern North Pacific evidence is emerging that gray whales (Eschrichtius robustus) are delaying their southbound migration, expanding their feeding range along the migration route and northward to Arctic waters, and even remaining in polar waters over winter--all indications that North Pacific and Arctic ecosystems are in transition. To use marine mammals as sentinels of ecosystem change, we must expand our existing research strategies to encompass the decadal and ocean-basin temporal and spatial scales consistent with their natural histories. [ABSTRACT FROM AUTHOR]

Blubber of seals, harbour porpoises and fish originating from the North Sea, the Baltic Sea, as well as coastal waters of Iceland and North America were analyzed for residues of polybrominated biphenyls. According to GC/ECNI-MS, hexabromobiphenyls (hexaBBs) dominated in the samples, followed by pentabromobiphenyls (pentaBBs) and heptabromobiphenyls (heptaBBs), whereas octabromobiphenyls (octaBBs) were only detected in selected samples and nonabromobiphenyls (nonaBBs) and PBB 209 were not found at all. Eleven peaks of hexaBBs—two peaks might have been each composed of two congeners, respectively—were detected in the different samples. The hexaBB pattern in samples of Iceland was a mixture of the pattern determined in samples from North America and continental Europe. In samples from the European continent, the major congener in technical hexabromobiphenyl, PBB 153, accounted for 11–37% of the hexaBBs. Other prominent isomers were PBB 155 (7.1–64%) and PBB 154 (11–33%), followed by PBB 133 as well as PBB 132 and/or PBB 146. Most of these PBBs were determined for the first time in marine biota and must be metabolites of higher brominated PBBs since they were not present in any technical product. PBB 153 was dominant in blubber of marine mammals from North America (92–96%). Blubber of harbour porpoises and also seal milk showed more peaks, which is indicative of a lower capability of biotransforming PBBs. It is concluded from this and other studies that PBB residues in North America are mainly originating from technical hexabromobiphenyl, while the bulk of the PBB residues in the European marine samples originated from technical octa- and decabromobiphenyl. Finally, it is evident from this study that a global ban of PBBs should not only be restricted to hexabromobiphenyls, but also needs to include higher brominated mixtures. [Copyright &y& Elsevier]