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This work resulted from the ARISE project (NE/P006035/1, NE/P006000/1), part of the Changing Arctic Ocean programme, jointly funded by the UKRI Natural Environment Research Council (NERC). We thank Jim Ball for his help in the isotopic lab in Liverpool University. This work resulted from the ARISE project, part of the Changing Arctic Ocean programme. Multiple environmental forcings, such as warming and changes in ocean circulation and nutrient supply, are affecting the base of Arctic marine ecosystems, with cascading effects on the entire food web through bottom-up control. Stable nitrogen isotopes (δ15N) can be used to detect and unravel the impact of these forcings on this unique ecosystem, if the many processes that affect the δ15N values are constrained. Combining unique 60-year records from compound specific δ15N biomarkers on harp seal teeth alongside state-of-the-art ocean modelling, we observed a significant decline in the δ15N values at the base of the Barents Sea food web from 1951 to 2012. This strong and persistent decadal trend emerges due to the combination of anthropogenic atmospheric nitrogen deposition in the Atlantic, increased northward transport of Atlantic water through Arctic gateways and local feedbacks from increasing Arctic primary production. Our results suggest that the Arctic ecosystem has been responding to anthropogenically induced local and remote drivers, linked to changing ocean biology, chemistry and physics, for at least 60 years. Accounting for these trends in δ15N values at the base of the food web is essential to accurately detect ecosystem restructuring in this rapidly changing environment. Publisher PDF

Hydrofoil-shaped limbs (flipper-hydrofoils) have evolved independently several times in secondarily marine tetrapods and generally fall into two functional categories: (1) those that produce the majority of thrust during locomotion (propulsive flipper-hydrofoils); (2) those used primarily to steer and resist destabilizing movements such as yaw, pitch, and roll (controller flipper-hydrofoils). The morphological differences between these two types have been poorly understood. Theoretical and experimental studies on engineered hydrofoils suggest that flapping hydrofoils with a flexible trailing edge are more efficient at producing thrust whereas hydrofoils used in steering and stabilization benefit from a more rigid one. To investigate whether the trailing edge is generally more flexible in propulsive flipper-hydrofoils, we compared the bone distribution along the chord in both flipper types. The propulsive flipper-hydrofoil group consists of the forelimbs of Chelonioidea, Spheniscidae, and Otariidae. The controller flipper-hydrofoil group consists of the forelimbs of Cetacea. We quantified bone distribution from radiographs of species representing more than 50% of all extant genera for each clade. Our results show that the proportion of bone in both groups is similar along the leading edge (0-40% of the chord) but is significantly less along the trailing edge for propulsive flipper-hydrofoils (40-80% of the chord). Both flipper-hydrofoil types have little to no bony tissue along the very edge of the trailing edge (80-100% of the chord). This suggests a relatively flexible trailing edge for propulsive flipper-hydrofoils compared to controller flipper-hydrofoils in line with findings from prior studies. This study presents a morphological correlate for inferring flipper-hydrofoil function in extinct taxa and highlights the importance of a flexible trailing edge in the evolution of propulsive flipper-hydrofoils in marine tetrapods.

The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter-specifically, spatially, and temporally. Because marine mammals occupy upper trophic levels in Arctic food webs, they may be useful indicators for understanding variation in ecosystem productivity. Polar bears (Ursus maritimus) are apex predators that primarily consume benthic and pelagic-feeding ice-associated seals. As such, their productivity integrates sea ice conditions and the ecosystem supporting them. Declining sea ice availability has been linked to negative population effects for polar bears but does not fully explain observed population changes. We examined relationships between spring foraging success of polar bears and sea ice conditions, prey productivity, and general patterns of ecosystem productivity in the Beaufort and Chukchi Seas (CSs). Fasting status (≥7 days) was estimated using serum urea and creatinine levels of 1,448 samples collected from 1,177 adult and subadult bears across three subpopulations. Fasting increased in the Beaufort Sea between 1983-1999 and 2000-2016 and was related to an index of ringed seal body condition. This change was concurrent with declines in body condition of polar bears and observed changes in the diet, condition and/or reproduction of four other vertebrate consumers within the food chain. In contrast, fasting declined in CS polar bears between periods and was less common than in the two Beaufort Sea subpopulations consistent with studies demonstrating higher primary productivity and maintenance or improved body condition in polar bears, ringed seals, and bearded seals despite recent sea ice loss in this region. Consistency between regional and temporal variation in spring polar bear fasting and food web productivity suggests that polar bears may be a useful indicator species. Furthermore, our results suggest that spatial and temporal ecological variation is important in affecting upper trophic-level productivity in these marine ecosystems.

Objective To assess whether corneal lesions in stranded pinnipeds were associated with viral infections, and to identify the potential pathogen(s) associated with the lesions. Animals studied Twenty-nine California sea lions (Zalophus californianus), 18 northern elephant seals (Mirounga angustirostris), and 34 Pacific harbor seals (Phoca vitulina richardsii). Procedure DNA and RNA were extracted from ocular swabs, corneal tissue, and aqueous humor and screened for herpesvirus, adenovirus, poxvirus, and calicivirus families by PCR. Results The results indicated a high overall prevalence of viruses, with adenoviruses and herpesviruses detected in all three host species. Three novel adenoviruses (PhAdV-1, PhAdV-2, OtAdV-2) and two novel herpesviruses (PhHV-6, OtHV-4) were detected. There were no statistical differences in the prevalence of viral infection or coinfection among groups of individuals with or without corneal lesions, nor were lesion type, onset, or presence of concurrent disease significantly associated with a viral infection. Conclusions The results suggested that viral presence in ocular tissues was common, not significantly associated with ocular disease and thus should not preclude release of an otherwise healthy animal. We could not confirm a correlation of virus presence with lesion due to the high percentage of virus-positive, clinically normal animals. This implied that seals and sea lions can have ocular tissues infected with several viruses without having readily evident associated lesions. This difficulty in correlating viral presence, particularly herpesviruses, with ocular lesions was also a common finding in studies with terrestrial species and highlighted the difficulty of confirming a virus as a primary pathogen in ocular lesions.

Ecologists often use transect surveys to estimate the density and abundance of animal populations. Errors in species classification are often evident in such surveys, yet few statistical methods exist to properly account for them. In this paper, we examine biases that result from species misidentification when ignored, and we develop statistical models to provide unbiased estimates of density in the face of such errors. Our approach treats true species identity as a latent variable and requires auxiliary information on the misclassification process (such as informative priors, experiments using known species, or a double-observer protocol). We illustrate our approach with simulated census data and with double-observer survey data for ice-associated seals in the Bering Sea. For the seal analysis, we integrated misclassification into a model-based framework for distance-sampling data. The simulated data analysis demonstrated reliable estimation of animal density when there are experimental data to inform misclassification rates; double-observer protocols provided robust inference when there were "unknown" species observations but no outright misclassification, or when misclassification probabilities were symmetric and a symmetry constraint was imposed during estimation. Under our modeling framework, we obtained reasonable apparent densities of seal species even under considerable imprecision in species identification. We obtained more reliable inferences when modeling variation in density among transects. We argue that ecologists should often use spatially explicit models to account for differences in species distributions when trying to account for species misidentification. Our results support using double-observer sampling protocols that guard against species misclassification (i.e., by recording uncertain observations as "unknown").

Understanding individual attitudes and how these predict overt opposition to predator conservation or direct, covert action against predators will help to recover and maintain them. Studies of attitudes toward wild animals rely primarily on samples of individuals at a single time point. We examined longitudinal change in individuals' attitudes toward gray wolves (Canis lupus). In the contiguous United States, amidst persistent controversy and opposition, abundances of gray wolves are at their highest in 60 years. We used mailed surveys to sample 1892 residents of Wisconsin in 2001 or 2004 and then resampled 656 of these individuals who resided in wolf range in 2009. Our study spanned a period of policy shifts and increasing wolf abundance. Over time, the 656 respondents increased agreement with statements reflecting fear of wolves, the belief that wolves compete with hunters for deer (Odocoileus virginianus), and inclination to poach a wolf. Endorsement of lethal control of wolves by the state and public hunting of wolves also increased. Neither the time span over which respondents reported exposure to wolves locally nor self-reported losses of domestic animals to wolves correlated with changes in attitude. We predict future increases in legal and illegal killing of wolves that may reduce their abundance in Wisconsin unless interventions are implemented to improve attitudes and behavior toward wolves. To assess whether interventions change attitudes, longitudinal studies like ours are needed. Analisis Longitudinal de las Actitudes Hacia Lobos.

Within the nasal cavity of mammals is a complex scaffold of paper-thin bones that function in respiration and olfaction. Known as turbinals, the bones greatly enlarge the surface area available for conditioning inspired air, reducing water loss, and improving olfaction. Given their functional significance, the relative development of turbinal bones might be expected to differ among species with distinct olfactory, thermoregulatory and/or water conservation requirements. Here we explore the surface area of olfactory and respiratory turbinals relative to latitude and diet in terrestrial Caniformia, a group that includes the canid and arctoid carnivorans (mustelids, ursids, procyonids, mephitids, ailurids). Using high-resolution computed tomography x-ray scans, we estimated respiratory and olfactory turbinal surface area and nasal chamber volume from three-dimensional virtual models of skulls. Across the Caniformia, respiratory surface area scaled isometrically with estimates of body size and there was no significant association with climate, as estimated by latitude. Nevertheless, one-on-one comparisons of sister taxa suggest that arctic species may have expanded respiratory turbinals. Olfactory surface area scaled isometrically among arctoids, but showed positive allometry in canids, reflecting the fact that larger canids, all of which are carnivorous, had relatively greater olfactory surface areas. In addition, among the arctoids, large carnivorous species such as the polar bear (Ursus maritimus) and wolverine (Gulo gulo) also displayed enlarged olfactory turbinals. More omnivorous caniform species that feed on substantial quantities of non-vertebrate foods had less expansive olfactory turbinals. Because large carnivorous species hunt widely dispersed prey, an expanded olfactory turbinal surface area may improve a carnivore's ability to detect prey over great distances using olfactory cues.

As part of population dynamics studies of the South American fur seal (Arctophoca australis gracilis) rookery at Punta Weather in Guafo Island (43°36'S, 74°43'W), the causes and extent of pup mortality were monitored. During four breeding seasons, daily counts of live and dead pups were carried out to determine pup production and pup mortality. Dead pups were retrieved from the rookery to perform necropsies. The mean pup production was 1,735.5 ± 336 pups and the mean pup mortality up to 12 wk old was 6.0% ± 2.6%. The major causes of death were enteritis with microscopic lesions of bacteremia (28.4%), starvation (23.5%), drowning (21%), trauma (19.8%), and stillbirths (2.5%). Enteritis with microscopic lesions of bacteremia, and starvation had higher incidence during January (beginning and middle of the breeding season) while most trauma and drowning occurred during February (end of the breeding season). In the 2006―2007 breeding season there was an increase in mortality due to starvation and trauma. Most pup deaths at Guafo Island are generated by extrinsic factors; therefore, additional studies that assess the impact of environmental changes and fishing activities, are needed in order to determine the exact causes of the decline of this species along Chilean coasts.

Summary 1. A major hypothesis of life-history theory is that conditions of early development affect future survival and reproductive success. Responses to detrimental environments during early ontogeny may involve trade-offs between current and future fitness. Yet, the functional mechanisms involved in such evolutionary trade-offs remain poorly documented. 2. The physiological and behavioural ontogeny of diving abilities was examined in subantarctic fur seal (Arctocephalus tropicalis Gray) pups to assess whether the repeated extreme fasts they naturally endure throughout the period of maternal dependence impacts on their development. 3. The ontogeny of pup body oxygen storage capacity was slow, in particular for the muscle compartment, which shows limited increase in myoglobin content (0·23–0·85 g 100 g wet muscle−1). As a consequence, by the time of weaning, mass-specific oxygen stores had only reached 76%, 24% and 61% of adult female capacity for blood, muscle and total, respectively. Concomitantly, in marked contrast to other pinniped infants, they spent decreasing amounts of time in water (16–7%) with age and exhibited very little diving experience and skills. 4. Overall, in addition to experiencing the longest fasting durations throughout the maternal dependence period, subantarctic fur seal pups demonstrate the lowest levels of mass-specific total oxygen stores and maximum dive duration of any otariid near the age of weaning reported to date. 5. Furthermore, dives that exceeded the calculated aerobic dive limit occurred with a very low frequency (0·04%), suggesting that behavioural limitations linked to the necessity to conserve energy to survive repeated fasting, rather than restricted oxygen storage capacity, constrained pup diving behaviour. 6. Hence, these animals appear to trade-off the early development of both their physiological and behavioural diving abilities in favour of body fat accumulation to survive the prolonged fasts they must endure and, potentially, provide a nutritional buffer while they locate appropriate food patches after weaning. While promoting pre-weaning survival, this strategy renders pups more vulnerable to unpredictable changes in environmental conditions and food availability at the transition to independent foraging and, thus, could have negative impact on post-weaning survival.

We estimated the seed shadow created by the Asiatic black bear Ursus thibetanus in order to evaluate the bears effectiveness as a seed disperser. We combined data from bear movements, determined by GPS telemetry, with data from gut retention time (GRT). We estimated plant seed shadows in two ways: from direct movement data to give the actual seed shadow (ASS), and from cumulative movement data to give the potential seed shadow (PSS). The purpose of this study was to answer the following questions: (1) does GRT differ between seasons or in the size of contents? (2) Does seed shadow vary among sex, seasons, estimation method (ASS or PSS), and years? (3) Does the masting affect seed shadows? There were no differences in median GRT among seasons or seed dimensions. Combining these data, the seed shadows produced by long GRT (median; 15.2-19.7 hours, maximum; 44.0 hours) and large daily movements suggest that the bears effectively move 40% of the seeds they consume to a distance greater than 500 m from the parent tree and can potentially move the seeds up to a maximum distance of more than 22 000 m from the parent tree. The results also indicate that bears make complex seed shadows caused by multiple defecations and long periods of daily movement. In summary, PSS did not differ between sexes, but PSS can be expected to be larger in autumn than in summer of each year. ASS, however, can be expected to be larger in males than females, and to be larger in autumn than in summer. ASS may become especially large during a poor masting year as compared to good masting years. These results indicate that bears are potentially more effective seed dispersers during years of poor fruit production in autumn. The bears have longer seed shadows than other seed disperser and consequently may play a unique role in the maintenance and renewal of forest ecosystem.

Total estimated abundance of Hawaiian monk seals was just 1,161 individuals in 2008 and this number is decreasing. Most monk seals reside in the remote Northwestern Hawaiian Islands (NWHI) where the decline is approximately 4%/yr, whereas relatively fewer seals currently occupy the main Hawaiian Islands (MHI). It is widely accepted that the MHI population is increasing, although there are no formal estimates of total abundance, population growth rate or vital rates. This lack of information has hampered efforts to anticipate future scenarios and plan conservation measures. We present the first estimates of MHI monk seal survival and age-specific reproductive rates. Using these rates, a conservative estimate of current MHI abundance and a previously published stochastic simulation model, we estimate the MHI population growth rate and projected abundance trend. Analogous estimates for the NWHI are derived from a much richer data set. Estimated survival from weaning to age 1 yr is 77% in the MHI, much higher than recent NWHI estimates ranging from 42% to 57%. Moreover, MHI females begin reproducing at a younger age and attain higher birth rates than observed in the NWHI. The estimated MHI intrinsic rate of population growth is 1.07 compared to a 0.89-0.96 range in the NWHI. Assuming an initial abundance of 152 animals in the MHI, projections indicate that if current demographic trends continue, abundance in the NWHI and MHI will equalize in approximately 15 yr. These results underscore the imperative to mitigate the NWHI decline while devoting conservation efforts to foster population growth in the MHI, where documented threats including fishery interactions, direct killing, and disease could rapidly undo the current fragile positive trend.

Increased terrestrial pup mortality in small colonies due to harassment by subadult males has been proposed as a mechanism to explain the stagnation of South American sea lion populations after sealing ended. To test this hypothesis, pup survival rate was assessed in five northern Patagonia colonies with different sizes. Female diet quality as well as pup growth rate and immune status from the largest and smallest of these colonies were also assessed. Results indicated that the pup survival rate increased with colony size and pup-to-subadult male ratio. Furthermore, pups grew faster in the smallest colony, although female diet composition and pup immune status did not differ between the two colonies. Inverse relationship between pup growth rate and survival rate indicated that mortality was independent of food supply. In absence of terrestrial predators, infanticide by subadult males is the only mortality source other than starvation and illness and the relationship between pup survival rate and pup-to-subadult male ratio approached a type II functional response curve. Thus, infanticide stands as the most likely reason for the observed positive relationship between colony size and pup survival rate, supporting the hypothesis that post-sealing population stasis was caused by inverse density dependence.

1. Using measurements of naturally occurring stable isotopes in animal tissues is useful for monitoring diets of wide-ranging species that would otherwise be logistically difficult to evaluate. However, differential metabolic routing of macromolecules within a consumer can be problematic when using stable isotope analysis of bulk tissues to trace dietary input. 2. We used stable isotope (δ13C, δ15N) analysis to examine polar bear Ursus maritimus diet, which includes both lipid-rich blubber and the proteinaceous tissues of their marine mammal prey. Because the proportion of proteins and lipids consumed may depend on prey type and size, it was necessary to consider metabolic routing of these macromolecules separately in isotope mixing models. 3. Bayesian mixing models (MixSIR, version 1.04) were used to separately estimate protein (δ13C, δ15N) and lipid (δ13C) dietary inputs. We used existing knowledge of the relative lipid and protein intake for polar bears and isotopic information from both macromolecules to estimate overall diet composition. 4. The results for both male and female polar bears indicated that smaller prey (e.g. ringed seal Pusa hispida) contributed the largest proportion to the protein-metabolic pathway. In contrast, the largest proportion of the lipid-metabolic pathway for both sexes tended to consist of larger prey (e.g. bearded seal Erignathus barbatus). 5. The diet composition of male polar bears consisted of more large than small prey. Diet estimates for females overlapped to some degree with males but tended to consist of less large prey. 6. Synthesis and applications. Monitoring polar bear diet may help determine the effects of climate-induced environmental changes in Arctic marine ecosystems including shifts in prey composition. Additionally, tracing origins of anthropogenic pollutants is currently a priority for wildlife managers concerned with the health of marine mammals. However, our results indicate using stable isotopes to infer dietary inputs when proportions of macromolecules fluctuate amongst food sources requires the sampling and analysis of multiple tissues representing distinct macromolecular metabolic pathways. In such cases, utilizing only proteinaceous tissues for analysis will result in erroneous dietary source estimates and inaccuracies when examining trophic-level transfer of contaminants, especially those that are lipophylic.

Summary 1. We present new developments in statistical methodology allowing in-depth analysis of realistic, complex biological models for longitudinal data sets. Important biological details such as mark-loss and recapture heterogeneity can be identified. 2. We use a Bayesian hidden process framework for a comparative analysis of long-term (1978–2006) capture–recapture data with various combinations of marking methods for adult female grey seals Halichoerus grypus at two UK colonies. 3. Seals were identified using three different methods: flipper tags, brands, or natural pelage markings. Animals identified by brands or natural markings were re-sighted more effectively than those with tags. 4. Flipper tag-loss rates differed between colonies, and there was evidence for non-independent tag-loss in double-tagged animals. There was also evidence at one colony for the presence of transient animals, which attend the colony for 1 year only. Apparent survival was higher and more consistent at one site, and the differences in survival between the two colonies were able to explain contrasting pup production trends at these sites. 5. Synthesis and applications. Longitudinal studies allow for the estimation of demographic parameters which have important implications for our understanding of population dynamics and for the conservation and management of populations. Using new statistical developments to allow for the analysis of missing/incomplete data and partial observations, we show how survival can be estimated from complex mark–recapture data, allowing for the effects of mark loss. The re-sightability of different marks is estimated, indicating that photo-ID based on natural pelage markings is a very effective method for identifying grey seals. There are notable contrasts in survival estimates between breeding colonies which can explain contrasts in population trends at these sites, confirming the importance of adult survival in driving population dynamics in this long-lived species.

Aim To determine the relationships between otter (Lutra lutra) distribution dynamics and environmental and spatial constraints over a 20-year period.Location Andalusia, southern Iberian Peninsula.Methods We synthesized otter distribution data from three otter surveys (1985, 1995 and 2005) using subcatchment areas defined by hydrological barriers. Subcatchments were characterized by two 'natural' (climatic and orographic variables) and two 'human' (land use and population density) gradients. In addition, we calculated two contagion variables (the distance to previously occupied subcatchments and the percentage of occupied subcatchments within a 50 km buffer) for consecutively surveyed subcatchments.Results Between 1985 and 2005 the percentage of subcatchments with otters present increased from 42% to 72%. Otters tended to be rare or absent from human-dominated areas. Anthropogenic gradients were better predictors of otter distribution than natural ones. Human and natural gradients showed strong covariation, but for any value of the natural gradients otters tended to be present in subcatchments with lower human impacts. Colonization of new subcatchments was found to be strongly related to contagion variables and expansion rates were slower than those estimated in other studies. Newly colonized areas tended to be located in areas with intermediate human influence, while repeated absences occurred mainly in areas where human impact was most severe.Main conclusions Our results suggest that recent otter expansion across Andalusia is a reflection of large-scale improvement in environmental conditions. Otter populations that survived the period of strong and generalized declines appear to be acting as sources from which neighbouring areas are colonized, probably aided by improved water quality and increases in food availability. However, the further expansion of otters into their full original range is likely to be constrained by human-impacted landscapes.

Climate change driven advances in the date of sea ice breakup will increasingly lead to a loss of spring polar bear foraging opportunities on ringed seal pups creating a phenological trophic ‘ mismatch ’ . However, the same shift will lead to a new ‘ match ’ between polar bears and ground nesting birds. Th is new match will be especially prevalent along the Cape Churchill Peninsula of western Hudson Bay where both polar bears and nesting snow geese are abundant. Easily foraged goose eggs will provide at least some of the earlier arriving polar bears with compensation for the energy defi cit accrued through lost seal hunting opportunities. We examine the potential impact of changes in the extent and pattern of polar bear egg predation on snow goose abundance using projection models that account not only for increases in the temporal overlap of the two species but also for autocorrelation and stochasticity in the processes underlying polar bear onshore arrival and snow goose incubation. Egg predation will reduce reproductive output of the nesting lesser snow geese and, under all but trivial rates, will lead to a reduction in the size of their nesting population on the Cape Churchill Peninsula. Stochasticity associated with the asymmetrical advances in polar bear onshore arrival and the snow goose incubation period will lead to periodic mismatches in their overlap. Th ese, in turn, will allow snow goose abundance to increase periodically. Climate driven changes in trophic matches and mismatches may reduce snow goose numbers but will not eliminate this over-abundant species that poses a threat to Arctic landscapes.

Summary 1. Many valuable contributions to the biology and conservation of harvested or previously harvested species have come from examination of specimens obtained by lethal collections. The northern fur seal Callorhinus ursinus on the Pribilof Islands, Alaska, has a long history of exploitation, including a large (>320 000) experimental harvest of females from 1955 to 1968 when the population was at a peak (� 2 million seals). The decline caused by this harvest was followed in 1977 by another major decline, apparently unrelated to harvest, that has recently accelerated. 2. To obtain current reproductive data that could be compared directly with historic estimates, we used imaging ultrasonography to estimate pregnancy rate in 171 adult fur seals captured on St. Paul Island, Alaska, in November, near the end of embryonic diapause. A modified logistic regression of pregnancy by date was used to estimate asymptotic pregnancy rate; a Bayesian hierarchical model based on date and size of embryonic vesicle was also used to account for pregnancies that were not detectable on the date of examination. 3. Pregnancy rate was high [0AE85 (SE = 0AE05), 0AE88 (SE = 0AE05) or 0AE92 (SE = 0AE04), depending on method] and there was little statistical support for the hypothesis that the current pregnancy rate is lower than the pre-decline rate (0AE84, SE = 0AE012) or contributing significantly to the present decline. 4. Synthesis and applications. Further study on intrauterine losses and pupping rates is necessary and ongoing, but reproductive ultrasonography provided an early comparative assessment important for the conservation management of this fur seal stock. It narrows the search for demographic and ecological causes of the population decline and allows research priorities to evolve in response to the likelihood of those causes. The field and analytic methods described have application to population assessments of other mammalian species, including those considered threatened or serving as ecosystem indicators.

Walleye pollock (Theragra chalcogramma) otoliths (n = 2,706) recovered from stomachs, small intestines, and colons of 43 northern fur seals (Callorhinus ursinus) were evaluated for size and wear by location in the digestive tract. Pollock fork length was regressed on otolith length after correction for erosion, and age was estimated from the calculated body size. Age-1+ pollock otoliths (≥6.3-mm length) were concentrated in stomachs while age-0 otoliths (≤6.2-mm length) were concentrated in colons. Less than 10% of otoliths were found in the small intestines. Pollock age decreased with progression along seal gastrointestinal tracts. Otolith quality increased along gastrointestinal tracts in numbers ≥20, which was typical of age-0 otoliths recovered from colons. Otolith distribution by age and quality along gastrointestinal tracts suggests that small (≤12 cm) schooling prey are consumed in large volume and passed as a bolus rapidly through the digestive tract before significant erosion of bony remains occurs; while larger prey are eaten in smaller volume and subjected to otolith erosion due to longer retention in the stomach. Our results illustrate the importance of multiple sampling strategies to comprehensively represent prey size in pinniped diet.

1. Carnivore overabundance that results from exploitation of human derived resources can have numerous detrimental effects on local human populations and ecological communities. Experimental studies on the responses of overabundant carnivores to reductions of such resources are necessary to understand the effectiveness and impacts of resource reduction.

There is limited research on the influence of Pacific-based climate in large herbivore populations. Additionally, much of our understanding on the effect of large-scale climate on ungulate population dynamics has occurred on forage-limited rather than predator-limited populations. We compared the influence of the Pacific Decadal Oscillation (PDO), North Pacific Index, and local weather on recruitment in a predator-limited mountain-dwelling caribou Rangifer tarandus caribou population in the Yukon Territory, Canada, across a range of wolf Canis lupus densities. A large-scale wolf removal program allowed us to examine the role of Pacific climate and weather when wolves were reduced to ∼15% of their pre-removal levels. Recruitment was best explained by the interaction of wolf density and April-PDO, with wolf density explaining the most deviance. Predicted recruitment during good springs was 0.45 (SE = 0.04) during wolf removal and 0.29 (SE = 0.03) with no wolf removal. During poor springs (low PDO, increased snow depth) predicted recruitment was 0.55 (SE = 0.10) during wolf removal and 0.12 (SE = 0.03) with no wolf removal. With non-altered wolf densities, there was a positive relationship between April-PDO and recruitment due to reduced snow depth at calving, allowing parturient females to disperse up in elevation away from predators. When wolf densities were substantially reduced there was a slight negative relationship between April-PDO and recruitment, possibly due to a more rapid vegetation green-up reducing the temporal availability of highly nutritious forage necessary for lactation and subsequent calf growth. Attempts to find general relationships between climate and ungulate population dynamics have proven difficult due to different ecological mechanisms by which climate affects individuals across populations. Temporally varying factors, such as predator density, may also play an important role in uncovering the mechanistic relationship between climate and population dynamics.

1. Identification of foraging behaviour and the ability to assess foraging success is critical to understanding individual and between-species variation in habitat use and foraging ecology. For pelagic predators, behaviour-dependent foraging metrics are commonly used to identify important foraging areas, yet few of these metrics have been validated. 2. Using the northern elephant seal as a model species, we validated the use of a behaviour-independent measure of foraging success (changes in drift rate) at the scale of the entire foraging migration, and then used this to assess a variety of common foraging metrics that are based on movement patterns and dive behaviour. Transit rate consistently provided the best estimate of daily foraging success, although the addition of other metrics provides insight into different foraging behaviours or strategies. 3. While positive changes in buoyancy occurred throughout most of the migrations, implying successful feeding across much of the north Pacific, the areas of most rapid changes in buoyancy occurred along a latitudinal band (40-50° N) corresponding to a dynamic hydrographic region including Subarctic Gyre and Transition Zone waters. 4. These results support the use of transit rate as an index of foraging success: a metric that is easily derived from tracking measurements on a wide range of marine species.

Five years of behavioral observations revealed significant effects of high air temperatures and breeding site topography on the mating system of South American sea lions in Peru. Unlike most polygynous mammals that defend females or fixed territories, male sea lions in Peru maintained positions along the shoreline where females passed each day to thermoregulate, and where most copulations occurred. Sex ratios (1 male per 17 females) and male mating success were extremely skewed (14% of males achieved 50% of the copulations, and 25% of them did not copulate at all). The mass daily movements of females toward the water and cool substrate of the shoreline, along with a highly skewed sex ratio, accentuated the difficulty for males to monopolize and restrict female movements. Females moved freely and chose their mates, unlike in temperate regions of their range where male South American sea lions control groups of females or access to tide pools. Our observations indicate that the South American sea lion in Peru has a lek-like breeding system. This is a rare alternative to the common male strategies of defending females and resources, and is likely an evolutionary product of their highly skewed sex ratio, protracted breeding season, and the extreme subtropical climate where they breed.

Development implies a change in allocation of resources from somatic growth to reproduction. In a highly variable environment, growth can vary from year to year thereby influencing the long-term life history perspective. The Galapagos sea lion (Zalophus wollebaeki) lives in a highly unpredictable marine environment in which food abundance varies not only seasonally, but also annually due to El Nino. Galapagos sea lions are restricted to a patch of cold upwelling waters surrounding the archipelago and are closely tied to land as nursing females alternate between foraging at sea and nursing ashore. Therefore, their offspring are especially vulnerable to ocean warming causing reduced food abundance. We found a significant correlation between sea surface temperature (SST) and early growth: Both mass at birth and linear growth within the first 2 mo of life correlated negatively with SST. Absolute mass gain was higher for males, but both sexes gained equally 1.9% of birth mass per day. Until the age of 3 yr male and female juveniles showed similar growth to an asymptotic mass of 40 and 35 kg, respectively. As a consequence of the highly variable environment, the plasticity in growth strategy of Galapagos sea lion juveniles appears wider than that of all other sea lions allowing them to cope with poor conditions.

Summary 1. Wolves Canis lupus recently recolonized the Western Alps through dispersal from the Italian Apennines, representing one of several worldwide examples of large carnivores increasing in highly human-dominated landscapes. Understanding and predicting expansion of this population is important for conservation because of its direct impact on livestock and its high level of societal opposition. 2. We built a predictive, spatially explicit, individual-based model to examine wolf population expansion in this fragmented landscape, and livestock depredation risk. We developed the model based on known demographic processes, social structure, behaviour and habitat selection of wolves collected during a 10-year intensive field study of this wolf population. 3. During model validation, our model accurately described the recolonization process within the Italian Alps, correctly predicting wolf pack locations, pack numbers and wolf population size, between 1999 and 2008. 4. We then projected packs and dispersers over the entire Italian Alps for 2013, 2018 and 2023. We predicted 25 packs (95% CI: 19–32) in 2013, 36 (23–47) in 2018 and 49 (29–68) in 2023. The SouthWestern Alps were the main source for wolves repopulating the Alps from 1999 to 2008. The source area for further successful dispersers will probably shift to the North-Western Alps after 2008, but the large lakes in the Central Alps will probably act as a spatial barrier slowing the wolf expansion. 5. Using the pack presence forecasts, we estimated spatially explicit wolf depredation risk on livestock, allowing tailored local and regional management actions. 6. Synthesis and applications. Our predictive model is novel because we follow the spatio-temporal dynamics of packs, not just population size, which have substantially different requirements and impacts on wolf–human conflicts than wandering dispersers. Our approach enables prioritization of management efforts, including minimizing livestock depredations, identifying important corridors and barriers, and locating future source populations for successful wolf recolonization of the

Effects of physiological processes such as gestation, lactation and nutritional stress on stable isotope ratios remain poorly understood. To determine their impact, we investigated these processes in simultaneously fasting and lactating northern elephant seals (Mirounga angustirostris). Stable carbon and nitrogen isotope values were measured in blood and milk of 10 mother-pup pairs on days 5 and 22 of lactation. As long- and short-term integrators of diet, blood cells and serum may reflect foraging data or energy reserves from late gestation and lactation, respectively. Limited changes in isotopic signatures of maternal blood over the lactating period were highlighted. Nitrogen isotope fractionation associated with mother-to-offspring

We provide the first direct evidence that Steller sea lions will prey on harbor seals. Direct observations of predation on marine mammals at sea are rare, but when observed rates of predation are extrapolated, predation mortality may be found to be significant. From 1992 to 2002, harbor seals in Glacier Bay declined steeply, from 6,200 to 2,500 (~65%). After documenting that Steller sea lions were preying on seals in Glacier Bay, we investigated increased predation by sea lions as a potential explanation for the large decline. In five independent data sets spanning 21-25 yr and including 14,308 d of observations, 13 predation events were recorded. We conducted a fine-scale analysis for an intensively studied haul-out (Spider Island) and a broader analysis of all of Glacier Bay. At Spider Island, estimated predation by sea lions increased and could account for the entirety of annual pup production in 5 of 8 yr since 1995. The predation rate, however, was not proportional to the number of predators. Predation by Steller sea lions is a new source of mortality that contributed to the seal declines; however, life history modeling indicates that it is unlikely that sea lion predation is the sole factor responsible for the large declines.

Predictable sources of food underpin lifetime reproductive output in long lived animals. The most important foraging areas of top marine predators are therefore likely to be related to environmental features that enhance productivity in predictable spatial and temporal patterns. Even so, although productive areas within the marine environment are distributed patchily in space and time, most studies assess the relationships between feeding activity and proximate, not long term, environmental characteristics. In addition, individuals within a population may exploit different prey types, and these are often associated with different hydrographic features. Until now, models attempting to associate core foraging areas (CFAs) of marine predators with the environmental characteristics of those areas have not considered the diet of individual animals, despite the influence this could have on these relationships. We used bathymetry and multi-year (n=24) mean sea surface temperature and variability as predictors of CFAs of lactating Antarctic fur seals Arctocephalus gazella at Heard Island. The effect of prey types on the predictability of these models was explored by matching diet and foraging trip data of individual seals (n=40 seals, n=1 trip each). Differences in diet between seals were mirrored by their spatial behaviour. Foraging strategies differed both between and within groups of seals consuming different diets. Long-term environmental parameters were useful for predicting the foraging activity of seals that consumed a single prey type with relatively specific habitat preferences, but not for those that consumed single or multiple prey types associated with more varied habitats. Ignoring individual variation in predator diet probably contributes to the poor performance of foraging habitat models. These findings highlight the importance of incorporating individual specialization in foraging behaviour into ecological models and management of predator populations.

Summary 1. In the Greater Yellowstone Ecosystem, bison Bison bison and elk Cervus canadensis nelsoni act as hosts for Brucella abortus. The presence of B. abortus within wildlife populations is an important conservation issue because of the risk of brucellosis transmission from wildlife to cattle. 2. We investigated conditions facilitating contact between bison (40–60% seroprevalence) and elk on a shared winter range in the Madison headwaters area of Yellowstone National Park. We evaluated the effects of snow pack, season, elk and bison population sizes, and wolf Canis lupus predation risk on the degree of spatial overlap between bison and elk from 1991 to 2006. 3. Sixty-eight per cent of 10 093 independent elk observations occurred within the known bison wintering range, 29% occurred within the distribution of bison within the winter range at the time of sampling and 14% occurred within 100 m of bison. Spatial overlap between bison and elk measured across these three spatial scales increased with week of the season, snow pack, and on days when wolves were within the same drainage area as elk, but decreased with cumulative levels of wolf predation risk. 4. Wolves contributed to immediate, short-term responses by elk that increased spatial overlap with bison, but longer-term responses to wolves resulted in elk distributions that reduced spatial overlap with bison. Spatial overlap increased through the winter and peaked when late-term abortion events and parturition occurred for bison. 5. Synthesis and applications. Despite this high level of association, elk exposure to B. abortus in the Madison headwaters (2–4%) was similar to those in free-ranging elk populations that do not intermingle with bison (1–3%), suggesting that B. abortus transmission from bison-to-elk under natural conditions is rare. Our results suggest that risk-driven elk behavioural responses to wolves are unlikely to have important disease implications. Management of brucellosis in greater yellow stone ecosystem elk populations should focus on reducing elk-to-elk transmission risk and, wherever possible, curtailing practices that increase elk density and group sizes during the potential abortion period.

The Guadalupe fur seal population at San Benito Islands is experiencing an exponential increase (r = 18.9%, r2 = 0.96) in this first phase of population growth. A similar pattern (r = 13.3%) was observed for Guadalupe fur seals from Gudalupe Island. The relatively rapid growth of the fur seal population on the San Benito Islands is due mainly to an increase in the number of females during the first 2 yrs and of juveniles during the last 2 yrs. The number of males and pups has been fairly constant over time. Apparently this first phase of population growth has been largely the result of the emigration of animals from GI; the only other breeding colony of the species.

Predators play integral roles in shaping ecosystems through cascading effects to prey and vegetation. Such effects occur when prey species alter their behavior to avoid predators, a phenomenon called the risk effects of predators. Risk effects of wild predators such as wolves are well documented for wild prey, but not for free ranging domestic animals such as cattle despite their importance for ecosystem function and conservation. We compared risk effects of satellite-collared wolves (n = 16) on habitat selection by global-positioning-system-collared elk (n = 10) and cattle (n = 31). We calculated resource selection functions (RSFs) in periods before, during and after wolf visits in elk home ranges or cattle pastures. The habitat variables tested included: distance to roads and trails, terrain ruggedness, food-quality and distance to forest. When wolves were present, elk stayed closer to forest cover and selected less for high-quality-food habitat. Thus, the risk effects of wolf presence on elk produced a change in the tradeoff between food and cover selection. Cattle responded by avoiding high-quality-food habitat and selecting areas closer to roads and trails (where people likely provided security), but these effects manifested only after wolves had left. Artificial selection in cattle may have attenuated natural anti-predator behaviors. The effects of predators on ecosystems are likely different when mediated through risk effects on domestic compared to wild animals. Furthermore, predator control in response to livestock predation, an important conservation issue, may produce broad ecosystem effects triggered by decrease of an important predator species. Conservation planners should consider these effects where domestic herbivores are dominant species in the ecosystem.

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: ϕ increased with pup age and was higher for pups born later in the season and to older mothers. Increases in ϕ 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 ϕ 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, ϕ 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.

1. Survival of a population can be influenced by foraging success that is determined by ecological and physiological factors. Foraging in air-breathing marine vertebrates is constrained by the duration of their dives, which is in part determined by their oxygen stores. Such organisms are excellent models to study how and when physiology limits behaviour and the associated role of ecological factors such as seasonal change. 2. The Galapagos sea lion (GSL) Zalophus wollebaeki is endangered and its population is declining. Previous work found that GSL exhibited three distinct foraging strategies during a warm season when resources are less abundant, possibly caused by intraspecific competition. 3. We examined adult female GSL diving behaviour during a cold, productive season compared to a warm season to test the hypothesis that they would converge onto one foraging strategy as a consequence of increased productivity. We investigated intra and inter-seasonal changes in GSL oxygen stores during a warm (March 2005, n = 11) and cold season (August-September 2006, n = 12) at Caamano Islet, Galapagos. 4. GSL exhibited persistence of three foraging strategies during the cold, productive season similar to those found during the warm season. This suggests that intraspecific competition associated with limited resources in this area of the Galapagos Islands is maintained throughout the year. 5. GSL exhibited contrasting seasonal changes in their oxygen stores. During the warm season haemoglobin (Hb) and blood volume (Bv) were significantly higher while myoglobin (Mb) was significantly lower compared to that in the cold season. Given that diving behaviour was similar between seasons, these changes are attributed to other causes such as pregnancy as most females were pregnant during the cold season. 6. GSL exhibited physiological plasticity within each season that was attributed to dive behaviour. Oxygen stores of the three foraging strategies, increased according to dive durations: haematocrit, Hb and Mb during the warm season and Hb, Mb and Bv during the cold season. 7. Knowledge of an organism's physiological plasticity is important to assess its vulnerability to climate change. We document for the first time inter and intraseasonal physiological response coupled with diving behaviour in the same sex and age class of an air-breathing diving vertebrate.

The age distribution of 865 lactating New Zealand sea lions (NZSLs; Phocarctos hookeri) was investigated over 3 yr (1999–2001) at two breeding colonies, Sandy Bay and Dundas Island, New Zealand. Lactating females were aged between 3 and 26 yr with a maximum observed age of 28 yr. The mean age of lactating females was 11.1 (SE = 0.16) yr. Age distributions peaked at ages 8 and 9 with a strong

Trade-offs between predation risk and forage fundamentally drive resource selection by animals. Among migratory ungulates, trade-offs can occur at large spatial scales through migration, which allows an "escape" from predation, but trade-offs can also occur at finer spatial scales. Previous authors suggest that ungulates will avoid predation risk at the largest scale, although few studies have examined multi-scale trade-offs to test for the relative benefits of risk avoidance across scales. Building on previously developed spatial models of forage and wolf predation risk, we tested for trade-offs at the broad landscape scale and at a finer, within-home-range scale for migratory and non-migratory resident elk (Cervus elaphus) during summer in the Canadian Rockies in Banff National Park (BNP) and adjacent Alberta, Canada. Migration reduced exposure to wolf predation risk by 70% relative to residents at the landscape scale; at the fine scale, migrants used areas that were, on average, 6% higher in forage digestibility. In contrast, by forgoing migration, resident elk were exposed to higher predation risk, but they reduced predation risk at fine scales to only 15% higher than migrants by using areas close to human activity, which wolves avoided. Thus, residents paid for trying to avoid predation risk with lower forage quality. Residents may have been able to compensate, however, by using areas of abundant forage close to human activity where they may have been able to forage more selectively while avoiding predation risk. Human activity effectively decoupled the positive correlation between high forage quality and wolf predation, providing an effective alternate strategy for residents, similar to recent findings in other systems. Although ungulates appear capable of balancing risk and forage at different spatial scales, risk avoidance at large landscape scales may be more effective in the absence of human-caused refugia from predation.

Aim We aimed to describe the large-scale patterns in population density of roe deer Caprelous capreolus in Europe and to determine the factors shaping variation in their abundance.

We estimated demographic parameters and harvest risks for polar bears (Ursus maritimus) inhabiting the Gulf of Boothia, Nunavut, from 1976 to 2000. We computed survival and abundance from capture–recapture and recovery data (630 marks) using a Burnham joint live–dead model implemented in program MARK. Annual mean total survival (including harvest) was 0.889 ± 0.179 ( ¯ x ± 1S E) for cubs, 0.883 ± 0.087 for subadults (ages 1–4), 0.919 ± 0.044 for adult females, and 0.917 ± 0.041 for adult males. Abundance in the last 3 yr of study was 1,592 ± 361 bears. Mean size of newborn litters was 1.648 ± 0.098 cubs. By age 7, 0.97 ± 0.30 of available females were producing litters. Harvest averaged 38.4 ± 4.2 bears/year in the last 5 yr of study; however, the 2002–2007 kill averaged

Steller sea lions (Eumetopias jubatus) have experienced a decline in Russia as well as the United States. The causes for the decline of the Russian population may or may not overlap the causes of the decline in Alaska. The demographics of the Russian population are not well understood and are an area of interest for scientists wishing to compare and contrast the Alaskan and Russian stocks. This study uses a unique observational system to assess survival by age at a small rookery on the Kamchatka Peninsula, Kozlova Cape. We proceeded under the hypothesis that changes in environmental conditions between years would produce noticeable differences in survival of pups born in those years. We found no evidence to support our hypothesis, but did find some differences from the Alaskan population in estimated survival for the juvenile stage class. This study also provides some of the history of Steller sea lions in Russia for context.

Summary 1 Corridors are commonly used to connect fragments of wildlife habitat, yet the identification of conservation corridors typically neglects processes of habitat selection and movement for target organisms. New technologies and analytical tools make it possible to better integrate landscape patterns with behavioural processes. We illustrate the integration of resource selection functions (RSFs) and least-cost path (LCP) analyses for the purpose of corridor planning for two large carnivores. 2 We used RSFs developed from Global Positioning System telemetry data to predict the seasonal distribution of two large carnivores: grizzly bears Ursus arctos and cougars Puma concolor. We then applied LCP analyses to identify potential corridors in two fragmented montane landscapes – Canmore and Crowsnest Pass – in Alberta, Canada. 3 Grizzly bear habitat selection in both areas positively correlated with greenness in all seasons and soil wetness and proximity to water in the summer when both variables were associated with bear forage. During spring, grizzly bear occurrence in Canmore inversely correlated with road density. 4 For cougars, habitat selection varied by region: it negatively correlated with road density in Canmore during non-winter and positively correlated with terrain ruggedness in Crowsnest Pass. Cougar occurrence during the non-winter season in Canmore positively correlated with greenness. 5 For each species, seasonal RSFs were used to develop a cost surface for LCP analyses to identify potential corridor locations in each study area. Overlaying the paths for the two species highlighted where the landscape could support corridors for both species and potential highway crossing zones. The telemetry data supported some of these modelled crossings. 6 Synthesis and applications. We show how to integrate RSFs and least-cost modelling to identify corridors for conservation. We focus on two large carnivores in the Canadian Rocky Mountains to identify potential corridors in Canmore and provide a framework for corridor planning in Crowsnest. We suggest that our approach is applicable to many other target species in addition to large carnivores in human-dominated landscapes.

Ecology Letters (2009) 12: 1347–1356 Abstract It is well established that ageing handicaps the ability of prey to escape predators, yet surprisingly little is known about how ageing affects the ability of predators to catch prey. Research into long-lived predators has assumed that adults have uniform impacts on prey regardless of age. Here we use longitudinal data from repeated observations of individually-known wolves (Canis lupus) hunting elk (Cervus elaphus) in Yellowstone National Park to demonstrate that adult predatory performance declines with age and that an increasing ratio of senescent individuals in the wolf population depresses the rate of prey offtake. Because this ratio fluctuates independently of population size, predatory senescence may cause wolf populations of equal size but different age structure to have different impacts on prey populations. These findings suggest that predatory senescence is an important, though overlooked, factor affecting predator-prey dynamics.

Recent increases in the height and growth ring width of willow (Salix spp.) and other woody plants in the Greater Yellowstone Ecosystem (GYE) have been attributed to a behaviorally mediated trophic cascade from wolves (Canis lupus) to elk (Cervus elaphus) to willows. This hypothesis predicts that individual elk consume less willow in response to the presence of wolves, but this prediction has not been directly tested with data from elk. We collected 727 fecal samples from elk in the Gallatin Canyon portion of the GYE over three winters and used microhistological methods to quantify the proportion of willow in each sample. We then tested the effect of wolf presence on willow consumption by elk, controlling for the effects of snow conditions, sex, and habitat type. During the period of study, 8-17 wolves occupied the study area, and wolves were locally present on 49% of 260 sampling days, stratified at two-week intervals across three drainages. Over the three years combined, willow consumption was related to snow conditions, wolf presence, and a wolf X sex interaction. As expected, willow consumption increased with deeper and less penetrable snow, and this effect was strong. Contrary to expectation, willow consumption increased in the presence of wolves. As with other aspects of antipredator behavior, wolves had different effects on willow consumption by males and females. Finally, we aggregated the data to estimate winter-long mean willow consumption within each drainage; at this broader scale, willow consumption again increased as predation risk increased. In summary, willow consumption was more strongly affected by snow conditions than by the presence of wolves. Interactions between elk and willow were affected by wolves, but not as predicted by the hypothesis that wolf presence favors willow release through a reduction in the selection of willow by individual elk. If a trophic cascade is operating, our results suggest that a decline in the size of the elk population (to roughly one-half its size immediately prior to wolf recovery) may be more important than changes in the willow consumption of individual elk. Finally, reduced grazing of herbaceous vegetation may be equally important for vegetation dynamics.

Sightings of killer whales around Shetland were recorded between 1991 and 2006 and for the whole of Scotland for 2007. The data were used to investigate temporal patterns in killer whale occurrence around Shetland and spatial patterns in occurrence around Scotland. 2. There was a strong seasonal peak in sightings around Shetland during June-July, coinciding with the harbour seal pupping season. 3. There was no clear trend in annual sightings around Shetland between 1991 and 2006. 4. Killer whales were sighted most frequently around Shetland and the Pentland Firth as well as around Mull and the Treshnish Isles. 5. These findings are discussed in terms of potential impacts upon local declining harbour seal populations and future research requirements. Copyrightr2009 John Wiley & Sons, Ltd.

As meat is a rich source of the omega-3 fatty acid docosapentaenoic acid (DPA) and Australians consume six times more meat than fish, investigation of the potential health benefit of DPA is warranted. The aims were to compare the effects of seal oil supplementation with fish oil, on measures of plasma lipids and blood pressure in hypertriglyceridaemic subjects. Forty-eight volunteers were recruited from the Wollongong community and were randomly allocated to one of three groups either receiving 1 g/day of long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) using one of three oils: seal oil capsules (340 mg eicosapentaenoic acid (EPA), 230 mg DPA, 450 mg DHA), fish oil capsules (210 mg EPA, 30 mg DPA, 810 mg DHA) or placebo capsules (containing sunola oil) for 6 weeks. Plasma triglycerides remained unchanged in the placebo group, whilst reductions of 7 and 14% (P < 0.05) were seen in the fish oil and seal oil groups respectively. Systolic blood pressure improved by 8 and 5 mmHg with seal oil and fish oil respectively (P < 0.05). The mean arterial pressure was significantly lower after seal oil supplementation (P < 0.005) compared with the placebo group. These results indicate that seal oil is as effective as fish oil in lowering plasma triglycerides and blood pressure.