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Surveys in England and the Moray Firth were funded by the UK Natural Environment Research Council (National Capability Grant no. SMRU1001). Surveys in the rest of Scotland were funded by Scottish Natural Heritage and surveys in Northern Ireland were funded by The Department of Trade and Industry, Marine Current Turbines, and the Northern Ireland Department of Agriculture, Environment and Rural Affairs. 1. Estimates of population size and trends are essential for effective conservation and management of wildlife populations. For harbour seals (Phoca vitulina), these data are required to fulfil statutory reporting obligations under national and international regulations. 2. Aerial survey counts of harbour seals hauled out during their annual moult were used to estimate population sizes and trends at UK, regional (seal management unit, SMU) and local (Special Area of Conservation, SAC) scales. 3. Results indicate that the current UK harbour seal population is similar to estimates from the late 1990s, but there were significant declines in some subpopulations and increases in others. 4. Fitted trends suggest that the UK harbour seal population can be divided into three geographically coherent groups: South‐east populations (South‐East and North‐East England SMUs) have shown continuous increases punctuated by phocine distemper virus epidemics in 1988 and 2002; north‐east populations (East Scotland, Moray Firth, North Coast and Orkney, and Shetland SMUs) have declined since the late 1990s; north‐west populations (West Scotland, Western Isles, and South‐West Scotland SMUs) have remained stable or increased. Similar geographical population substructure is evident in recent population genetics results. 5. Trends within SACs generally match SMU trends since 2002. Of the nine SACs designated for harbour seals, four declined (in East Scotland, Moray Firth, and North Coast and Orkney SMUs), four remained stable (in Shetland and West Scotland SMUs), and one increased (in South‐East England SMU). 6. Large changes in relative abundance have resulted from differences in regional trends. For example, in 1996–1997 the West Scotland and North Coast and Orkney SMUs each held ~27% of the Great Britain population but now hold ~50% and ~4% respectively; in 1980, the South‐East England SMU population was ~50% that of the Wadden Sea population, but by 2016 it was equivalent to

The work was supported by funding from the Natural Environment Research Council to SMRU (grant no. SMRU1001). 1. The population size of many species, particularly those in the aquatic environment, cannot be censused directly. Counts, during the breeding season, of one component of the population (e.g. breeding females) are often used as an index to allow investigation of trends. In species, such as grey seals (Halichoerus grypus), for which births are not tightly synchronous, single counts of pups represent an unknown proportion of the total number of pups born (pup production), and thus of breeding females (i.e. each pup born represents a breeding female). 2. Grey seals pup at large colonies around the coast of the UK. Information on their populations is required under national and international legislation. 3. In the UK, pup production has been monitored at some colonies since 1956. Currently, large colonies (~90% of UK pup production) are monitored either using ground (~10%; annually) or aerial surveys (~80%; annually until 2010, and thereafter biennially). 4. Here, the model used to estimate pup production at aerially surveyed colonies from 1987 to 2010 is described; structured pup counts from multiple surveys are combined with knowledge of life‐history parameters to model birth curves. 5. The resulting trends in pup production up to 2010 (aerially surveyed colonies) and 2016 (ground surveyed colonies) are examined. 6. In 2010, over 45,000 pups were estimated to be born in the UK. Pup production appeared to have reached an asymptote in the Inner Hebrides, Outer Hebrides and Orkney, whereas it is still increasing exponentially in the North Sea. Although density‐dependent processes acting at sea are likely to be responsible for these regional trends, we suggest that the substantial variation in trends within regions are likely caused by processes acting at the colony level. Some long‐established colonies, including Special Areas of Conservation, are exhibiting decreasing trends. 7. Special Areas of Conservation often serve as de facto monitoring sites and are the focus of management efforts. The observed temporal and spatial variability in patterns of colony growth rates highlight the potential risks of using such sites to develop wider management policies. Postprint

Aerial surveys have detected alarming declines in counts of harbour seals in several regions across Scotland. Demographic data and simple models were used to examine the recent decline in the numbers of harbour seals counted in one population within a Special Area of Conservation (SAC) on the east coast of Scotland. The models suggest that the continuation of current trends would result in the species effectively disappearing from this area within the next 20 years. While the cause of the decline is unknown, it must be reducing adult survival because the high rate of decline cannot be wholly accounted for by changes in other demographic parameters. Recovery of the population to the abundance recorded at the time the SAC was designated (2005) is likely to take at least 40 years, even if the cause of the decline is immediately identified and removed. The models suggest that partial removal of the cause can have only limited benefits to population recovery, and there are unlikely to be any long-term benefits from introducing or reintroducing additional individuals while the underlying problem persists. Therefore, if the population of harbour seals in this area is to recover it is essential that the sources of the increased mortality are identified and measures are put in place to manage these. Copyright © 2015 John Wiley & Sons, Ltd.

During 2009 and 2010 an Acoustic Deterrent Device (ADD) was tested at a salmon bagnet. Treatment blocks when the ADD was either on or off were randomly assigned and observations were carried out from shore. During periods when the ADD was switched on, there were fewer seals observed and approximately a third more fish were landed per hour than when the ADD was switched off, these differences were both significant. Model results indicated that the higher fish landings when the ADD was operating were a direct result of the reduction in the number of seals in the vicinity of the net. Photo-identification of the seals resulted in ten grey seals and four harbour seals being identified, and showed that the majority of these were identified on one occasion, and that two grey seals made up 63% of the visits to the study area when individuals were identified. Seal-damaged fish were only found within the bagnet during off treatments. Overall, the ADD was found to be an effective seal deterrent. Refinement in the method of ADD deployment could further increase effectiveness.

Grey seal pup production in Scotland was estimated through annual aerial surveys of the main grey seal breeding colonies. Between 3 and 7 counts of pups were obtained for each colony at intervals through the course of the breeding season. Pup production for individual colonies was estimated from the series of counts using a maximum likelihood model. At 3 colonies, 2 in England, annual pup production was estimated using ground counts. Between the early 1960s and the early 1990s, grey seal pup production progressively increased. At colonies in the Inner and Outer Hebrides, production appeared to stabilize during the 1990s and has remained so. Pup production at colonies in Orkney and in the North Sea has continued to increase but in recent years the rate of increase has declined. This may imply that the UK grey seal population is reaching some limit to its size. The observed changes in pup production imply that some density dependent factors are affecting the British grey seal population. Changes in either juvenile survival and/or female fecundity are the most likely options. Without knowing which of these, or what combination of these factors, is operating, estimating total population size is complicated.

1. The annual cycle of many animals is characterized by the need to satisfy different life history priorities, often requiring seasonal movements. For such species, investigating carryover effects (such as the year-long drivers of breeding success) and managing protected areas effectively, relies on quantifying these movements. Here, we model the seasonal movements of the UK population of grey seals Halichoerus grypus and show how insights from the model can improve its management. 2. We fit a hidden process model to two types of information – regional population redistribution and individual movements – to estimate the seasonal transition probabilities of breeding female grey seals among four regions around the UK. 3. We found that between 21% and 58% of females used different regions for breeding and foraging. 4. For our study period, we detected an increase in the breeding performance of animals that foraged in the Hebrides and South-East Coast. 5. Grey seal Special Areas of Conservation (SACs) were designed to encompass a significant proportion of the UK breeding population: ~ 40% of the breeding females in our study area. Of the females breeding on SACs, only 15% breed in Northern Scotland, but up to 50% forage there. Our results indicate that, by only considering the breeding distribution of females that breed in SACs, the impact of anthropogenic activities on nearby SACs may be overestimated, whereas impacts on remote SACs may be underestimated. 6. Synthesis and applications. By quantifying the link between the foraging and breeding distributions of grey seals, management of breeding populations can be focused on the foraging regions where the resources necessary for reproduction are acquired. The construction of marine developments is dependent on demonstrating that they will not have an adverse effect on the integrity of Special Areas of Conservation (SACs), and we have shown that this requires consideration of the seasonal transition probabilities estimated in this study. Our specific results provide support for management strategies that jointly consider SACs and Marine Protected Areas (MPAs). More generally, we prescribe combinations of data on population size, breeding performance and individual movement that can enable our framework to be applied to seasonally migrating species.

Estimates of both absolute abundance and trends in abundance are among the most basic pieces of information required for planning the conservation and management of wildlife populations. They are important for understanding both the current situation of species and potential risks to them. This study presents estimates of the size of the harbour seal (Phoca vitulina) population associated with the Orkney Islands, a part of northern Scotland that used to contain one of the largest concentrations of this species in Europe. The numbers of animals counted during aerial surveys of this area have decreased substantially over the period 2001–2010. ARGOS transmitters attached to flipper tags were used to rescale the counts into estimates of abundance and to confirm the rate of decline of this population. Females hauled out for more of the survey window (0.84; bootstrap 95% CI: 0.63–0.99) than males (0.61; bootstrap 95% CI: 0.34–0.86). The animals hauled out less during weekends (0.57; bootstrap 95% CI: 0.40–0.74) than during the week (0.76; bootstrap 95% CI: 0.58–0.91). The sex-ratios of this population is unknown. Assuming it was close to 1:1, then there were around 3586 (bootstrap 95% CI: 2970–4542) harbour seals in Orkney in 2010. A female-skewed sex-ratio would reduce the population estimate, and a changing sex-ratio might mean the counts understate the real decline. The mean annual rate of decline in the Orkney population of harbour seals, over the period 2001–2010, is estimated at 13% (95% CI: 10.8–14.8). Similar data for Arisaig, on the west coast of Scotland, shows an increase of around 2% (95% CI: 1.5–2.4) and, assuming an equal sex-ratio, 923 animals (95% CI: 765–1169) in 2007. Copyright © 2012 John Wiley & Sons, Ltd.

Regime shifts are sudden changes in ecosystem structure that can be detected across several ecosystem components. The concept that regime shifts are common in marine ecosystems has gained popularity in recent years. Many studies have searched for the step-like changes in ecosystem state expected under a simple interpretation of this idea. However, other kinds of change, such as pervasive trends, have often been ignored. We assembled over 300 ecological time series from seven UK marine regions, covering two to three decades. We developed state-space models for the first principal component of the time series in each region, a common measure of ecosystem state. Our models allowed both trends and step changes, possibly in combination. We found trends in three of seven regions and step changes in two of seven regions. Gradual and sudden changes are therefore important trajectories to consider in marine ecosystems.

Lonergan, M., Duck, C. D., Thompson, D., Moss, S., and McConnell, B. 2011. British grey seal (Halichoerus grypus) abundance in 2008: an assessment based on aerial counts and satellite telemetry. – ICES Journal of Marine Science, 68: 2201–2209. Recent estimates of the total size of the British grey seal population have been based on fitting age-structured models to estimates of pup production. The estimates were sensitive to whether density-dependence was considered to act on fecundity or pup survival. This study provides an alternative estimate for abundance in 2008: 91 800 animals (95% confidence interval, CI, 78 400–109 900). The estimate is consistent with the results of existing models where population density influences pup survival. It suggests that reductions in fecundity are unlikely to have been the cause of the recent slowing of the rate of growth of the population. The estimate presented is based on aerial surveys of the entire Scottish coast and the east coast of England. The surveys were carried out in August of 2007–2009 and restricted to the 2 h each side of daylight low water. Data from 107 electronic tags deployed between 1995 and 2008 were used to estimate the proportion of animals hauled out during the surveys. Overall, the animals hauled out for 31% (95% CI 15–50%) of the survey windows. No significant effects on the proportion of animals hauled out were detected from year, location, age, sex, temperature, rainfall, or the timing of low tide.

There have been marked declines of UK harbour seal populations over at least the last decade. Protected areas, such as Special Areas of Conservation (SACs), provide one tool to improve the conservation status of these populations. However, the design and management of SACs is often limited by a lack of information on long-term patterns in the use of seal haul-out sites and foraging areas. The Moray Firth is the only UK region where long-term harbour seal population studies have been conducted in parallel with detailed studies of foraging ecology. We used this opportunity to investigate changes in the use of haul-out sites and foraging areas within two adjacent estuaries, where annual haul-out counts were made over a 20-year period. In 1988, >99% of seals and all mother-pup pairs were located at haul-out sites within an area that was subsequently designated as a SAC to protect harbour seals. In addition to previously reported declines in this area, we detected a shift in haul-out distribution resulting from the development of a new pupping site that, by 2008, held 37% of mother pup pairs in the area. Foraging areas of breeding females were compared in 1989 and 2009 using a combination of VHF and GPS–GSM telemetry, confirming that females foraged in broadly similar areas in both periods. This suggests that the development of this new pupping site was not driven by the need to forage further offshore, but instead was more likely due to local variation in haul-out site characteristics. These results are discussed in relation to potential drivers of haul-out site choice and the need to develop a broader suite of measures for managing habitat quality within this and other SACs for harbour seals.

This work was funded by Natural Environment Research Council (NERC) grant NE/J02080X/1. The Rothamsted Insect Survey (RIS) is a National Capability strategically funded by BBSRC. Differences in phenological responses to climate change among species can desynchronise ecological interactions and thereby threaten ecosystem function. To assess these threats, we must quantify the relative impact of climate change on species at different trophic levels. Here, we apply a Climate Sensitivity Profile approach to 10,003 terrestrial and aquatic phenological data sets, spatially matched to temperature and precipitation data, to quantify variation in climate sensitivity. The direction, magnitude and timing of climate sensitivity varied markedly among organisms within taxonomic and trophic groups. Despite this variability, we detected systematic variation in the direction and magnitude of phenological climate sensitivity. Secondary consumers showed consistently lower climate sensitivity than other groups. We used mid-century climate change projections to estimate that the timing of phenological events could change more for primary consumers than for species in other trophic levels (6.2 versus 2.5–2.9 days earlier on average), with substantial taxonomic variation (1.1–14.8 days earlier on average). Postprint

The status of Ireland's harbour seal Phoca vitulina vitulina population is poorly understood. The most recent national population estimate dates back to the breeding season in 1978 and did not cover the entire coastline. Reliable up-to-date information on the abundance and distribution of harbour seals in Ireland is necessary to assess the conservation status of the species and for the effective identification, management and monitoring of special areas of conservation required for harbour seals under the EU Habitats Directive. To provide comprehensive current information on Ireland's harbour seal population, a geographically extensive survey was conducted along the coastline of the Republic of Ireland during the species' annual moult in August 2003. This complemented a similar survey of Northern Ireland, which was conducted in 2002. Using thermal imaging technology, haul-out groups of harbour seals and grey seals Halichoerus grypus were identified from the air, aerial-counts were obtained and compared with simultaneous ground-count data from selected sites. Harbour seal distribution recorded during the 2003 moult season was concentrated in the south-west, west and north-west of the country. This national survey yielded a minimum population estimate for the Republic of Ireland of 2905 harbour seals, delivering an effective baseline for current and future population research.

This study presents an analysis of changes in the regional abundance of harbour seals Phoca vitulina based on repeated aerial surveys of haulouts, and demonstrates the use of sparse data to deliver advice about population status and management. Generalized linear models with negative binomial errors were used to represent these overdispersed data. The shape parameter of the negative binomial distribution was directly estimated from the data where this was possible. Information from time-series of counts where there were few gaps in the data was used to improve the estimation of this parameter in areas where fewer surveys had been carried out. The results show that the number of harbour seals in eastern England has not increased since the end of the 2002 phocine distemper epidemic. There is also evidence of a general decline in most of the large harbour seal colonies around Britain. The populations in the Inner Hebrides were an exception, with numbers appearing to be stable or increasing. Between 2001 and 2006, the population in Orkney and Shetland declined by 40% (95% confidence interval: 30–50%), indicating harbour seals in these areas experienced substantially increased mortality or very low recruitment over this period. The widespread declines, ranging from Shetland to The Wash, suggest that the causes may have been present over a large part of the North Sea.

Conservation efforts are often constrained by uncertainty over the factors driving declines in marine mammal populations. In Scotland, there is concern over the potential impact of unrecorded shooting of seals, particularly where this occurs near Special Areas of Conservation. Here, we show that the abundance of harbour seals Phoca vitulina in the Moray Firth, north-east Scotland, declined by 2–5% per annum between 1993 and 2004. Records from local salmon fisheries and aquaculture sites indicated that 66–327 harbour seals were shot each year between 1994 and 2002. Matrix models and estimates of potential biological removal indicate that this level of shooting is sufficient to explain observed declines. Nevertheless, uncertainty over the number and identity of seals shot means that other factors such as changes in food availability may be contributing. Recent conservation measures markedly reduced the recorded levels of shooting in 2003 and 2004. In 2005, a coordinated management plan was developed to protect salmon fisheries interests while minimizing impacts on local seal populations. Comprehensive monitoring of future population trends and improved regulation of culls are now required to provide more robust assessments of the impact of human persecution on harbour seal populations in the Moray Firth and in other parts of the UK.

More than 10,000 Caspian seals ( Phoca caspica) were reported dead in the Caspian Sea during spring and summer 2000. We performed necropsies and extensive laboratory analyses on 18 seals, as well as examination of the pattern of strandings and variation in weather in recent years, to identify the cause of mortality and potential contributory factors. The monthly stranding rate in 2000 was up to 2.8 times the historic mean. It was preceded by an unusually mild winter, as observed before in mass mortality events of pinnipeds. The primary diagnosis in 11 of 13 seals was canine distemper, characterized by broncho-interstitial pneumonia, lymphocytic necrosis and depletion in lymphoid organs, and the presence of typical intracytoplasmic inclusion bodies in multiple epithelia. Canine distemper virus infection was confirmed by phylogenetic analysis of reverse transcriptase-polymerase chain reaction products. Organochlorine and zinc concentrations in tissues of seals with canine distemper were comparable to those of Caspian seals in previous years. Concurrent bacterial infections that may have contributed to the mortality of the seals included Bordetella bronchiseptica (4/8 seals), Streptococcus phocae (3/8), Salmonella dublin (1/8), and S. choleraesuis (1/8). A newly identified bacterium, Corynebacterium caspium, was associated with balanoposthitis in one seal. Several infectious and parasitic organisms, including poxvirus, Atopobacter phocae, Eimeria- and Sarcocystis-like organisms, and Halarachne sp. were identified in Caspian seals for the first time.

Summary 1 Harbour seals Phoca vitulina in eastern England were heavily exploited in the 1960s and 1970s, and affected by phocine distemper virus (PDV) epidemics in 1988 and 2002. Information on their historical and current status is required for their management. To maximize the effectiveness of limited population survey effort we need to both estimate and minimize error. 2 Presented here are data from annual aerial surveys of the population. Sporadic, synoptic surveys in The Wash, England, were used with more frequent counts of subpopulations in the Moray Firth, Scotland, to determine optimum timing of surveys. 3 We developed models that explicitly account for variability in both observation and population growth processes to show that the proportion of animals observed is much more variable than the annual growth rates. The latter can therefore be treated as constant within each period, and estimated along with the epidemic mortalities during the study and the precision of the survey results. 4 The Wash population increased at around 3·1% per annum (pa) [95% confidence interval (CI) 2·1–4·1] between 1973 and 1988. It fell by approximately 52% (95% CI 44–59) as a result of the 1988 PDV epidemic, and subsequently increased at 5·7% pa (95% CI 4·8–6·7). These growth rates were below those reported for European mainland populations, but showed no indication of density-dependent effects. 5 The recurrence of PDV in 2002 caused approximately 22% mortality (95% CI 9–33), significantly less than the 1988 epidemic and less than half that in European mainland populations in 2002. 6 Synthesis and applications. Combining sparse, systematic survey data with sporadic counts produced robust estimates of growth rates and epidemic mortality. The results indicate the value of even limited and sporadic survey effort for monitoring populations. The study has highlighted significant differences in both population dynamics and the severity of disease events between English and European harbour seal populations.

Pup production of southern sea lions in the Falkland Islands was estimated to be 80,550 (total population ca. 380,000) in 1937, but by 1965 it had fallen to around 6000; a 93% reduction in under 30 years. We describe the results of an aerial survey of part of the breeding population in 1990 and comprehensive ground counts of the entire population in 1995 and 2003. Results indicate that the decline continued. In 1995, 63 breeding and 42 non-breeding groups were found. Pup production was estimated at 2034 pups; less than 2.7% of the 1930s estimate. All known and potential sites were revisited in 2003. 2747 pups were counted at 68 breeding sites, seven of which were new since 1995. Results indicate that between 1965 and 1990 the population reached a minimum of less than 1.5% of the 1937 population. Since then, pup production has increased at a rate of 8.5% p.a. between 1990 and 1995 and at 3.8% p.a. between 1995 and 2003. The Falklands' trajectory is similar to that of the adjacent Argentinian population. The causes of these declines are not clear. Around 44,000 sea lions were killed in the Falklands between 1935 and 1962, more than 500,000 were taken in Argentina in the same period. We present the results of a simple population model which suggests that, if sea lions migrated between the two areas, the combined hunt may explain the initial decline in the Falklands population. However, the continued decline after 1965 is as yet unexplained.

Phocine distemper virus (PDV) may have killed a small number of grey seals Hali- choerus grypus in European waters in 2002, as it was thought to have done in 1988. PDV is known to affect harbour seal population and distribution patterns, but grey seal pup production trends did not correlate consistently with PDV outbreaks. Numbers of known mothers missing from study colonies do not increase in PDV years and pre-weaning pup mortality is similar to that in other years. Pup growth rates are similar in PDV and non-PDV years. Therefore, no direct evidence links PDV out- breaks to changes in grey seal reproductive parameters at the population, colony, or individual level. Investigation of exposure of grey seals to PDV used CDV virus-neutralisation tests on sera collected from breeding seals pre-1988, 1988, 2001 and 2002. No positive sera (≥titre 1:64) were detected prior to 1988. In 1988, 2001 and 2002 the prevalence was 96, 59 and 83%, respectively. In 2001, prevalence in 'old' mothers (of breeding age by 1988, ≥13 yr old) was 63% compared to 0% in 'young' mothers (born after 1989

Pre-weaning pup mortality of grey seals Halichoerus grypus in a breeding colony (North Rona, Scotland, U.K.) was examined in relation to the density of local adult females over two breeding seasons. Accurate, fine-scale maps of daily seal locations within a GIS database permitted the extraction of measures of female density determined at a range of spatial scales from 5 to 50 m around each pup on the date of death. Adult densities around live pups provided the null distribution of adult densities, which were tested against the distribution of densities where deaths occurred. Pre-weaning pup mortality at this colony was not related to any of our density measures. The proportion of pups dying each day showed no seasonal trends. Analysis of topographic features from a sub-meter digital terrain model for locations where deaths occurred suggested that there were fewer mortalities in prime pupping habitats. This could have been a direct effect of habitat or the relative quality of mothers in these habitats. The distance separating mothers and pups tended to be greater on the periphery of the colony compared to more central areas. Pups in the peripheral areas may be more exposed to predation by gulls.

Many phocids are capital breeders, relying on stored reserves to sustain energetic requirements while on land. Their large body size, high energy expenditure during lactation, and the insulative effects of the blubber layer can lead to thermal stress from overheating, especially in warm and temperate climates. Thermal stress can influence fine-scale site choice on breeding colonies, and behavioral thermoregulation has been proposed as an explanation for the clear preferences shown by breeding female gray seals for proximity to pools of water. However, anecdotal observations suggest that pools of water may also be preferred for drinking, though water intake is difficult to verify without real-time physiological monitoring. Here, an alternative approach demonstrates that gray seals also require access to water for drinking. Using Ecological Niche Factor Analysis to examine fine-scale physical determinants of pupping site choice at North Rona, Scotland, we found that lactating mothers showed preference for lower salinity pools. This is most pronounced early in the season, when ambient temperatures and presumably thermal stress are greatest. Given that the cooling effect of fresh and salt water should be equivalent, the most parsimonious explanation for this preference for fresh water pools is that lactating females use these pools for drinking. Postprint

Until the mid 1970s only a few grey seal Halichoerus grypus pups were born each year on the Isle of May, Scotland, but 1408 pups were born there in 1994. We examined changes in overall site use, individual pupping site fidelity and success in relation to local population density and topography. The area of the island used by seals for breeding has increased as the population increased. Between 1988 and 1994 an index of the proportion of the island's northern area occupied by seals increased from 0.48 to 0.65, while the average population density in these occupied areas decreased over the same period. Although seals have begun to breed in southern parts of the island that were unused previously, other apparently suitable breeding areas on the island remain vacant. Fine scale digital elevation models were constructed using a GIS to evaluate the topographic characteristics of occupied areas and assign topographic ‘costs’ to areas used by seals for breeding on the Isle of May. Seals were associated generally with areas close to the numerous access points from the sea. New areas occupied in the later years of the study had a higher topographical ‘cost’ than the traditional sites. Thus, in an expanding colony such as the Isle of May, areas colonized early in the colony's history were those close to access points and/or standing water and at low elevations. Subsequent expansion resulted in an increase in the areas occupied by seals, but these newly colonized areas were less suitable, and their occupiers were subject to increased topographic ‘costs’. Pup mortality rates were similar in areas of high and low breeding density. Aggressive behaviour between breeding females is the likely mechanism which acts to limit local animal density. Mothers marked at the Isle of May since 1987 returned there to breed with few exceptions, and most females that returned were faithful to their previous pupping sites (median distance between sites used in consecutive breeding seasons = 25 m). Site fidelity persisted even when a previous pupping was unsuccessful and most individuals' pupping locations did not change gradually with time. Comparison with other colonies suggests that the spatial scale of site fidelity is related to the scale of topographic variation within the breeding site.

Organochlorine contaminants (pesticides and individual polychlorinated biphenyl congeners, PCBs) were measured in Caspian (Phoca caspica) seal blubber and compared with concentrations in Harbour (Phoca vitulina) seal blubber. Concentrations of total dichlorodiphenyltrichloroethane (DDT) and its metabolites were significantly higher in Caspian seal than Harbour seal samples, whereas PCB congeners were significantly higher in Harbour than Caspian seals. Our finding suggests that Caspian seals are exposed to high levels of DDT pesticides. In contrast, PCBs are circulating in this population at much lower levels than in marine mammals from the North Sea.

This study investigated the foraging behaviour, diving behaviour, movements and diet of lactating southern sea lions in the Falkland Islands. They appeared to be primarily nocturnal, benthic foragers hunting at depths ranging from the surf line down to 250 m, and from just off their breeding sites out to 45 km offshore. Occasional longer trips may extend foraging ranges to over 150 km from breeding sites. Attendance patterns suggest that Falklands' sea lions do not haulout simply to feed their pups. Other factors such as predation and thermoregulation may cause them to come ashore. When at sea they travelled at approximately 1 m s −1 , slower than previous studies of otariids indicated. Absence from the breeding site did not imply continuous foraging; all study animals used remote haulout sites away from their pups. Repeated use of the same areas and the short duration of foraging trips suggest that they were able to catch enough food within a fairly small foraging range. Data on diet support the suggestion that lactating sea lions are mainly benthic foragers. They take a wide range of prey species. The most common cephalopods were Loligo gahi , similar in size to those taken by the fishery. There is therefore potential for competition between the sea lion population and the Loligo trawl fishery. There was considerable overlap between the diet of sea lions and those of Gentoo and Magellanic penguins, which suggests that sea lions may compete with both species.

The timing, location and duration of territorial tenure, and the mating success and return rates of male Antarctic fur seals (Arctocephalus gazella) were measured over four consecutive breeding seasons (1984–87) on Bird Island (54°00'S, 38°02'W), South Georgia. Tenure duration (days) followed a heavily skewed, Poisson-like distribution (median 13.08 days, maximum 75 days) and was positively related to the number of years of tenure (rs= 0.52, P 0.05 in both cases). The probability of a male returning to hold a territory in the next year was not related to the number of years tenure that had been achieved (P > 0.7) or to the level of mating success in the current year (P > 0.15). It was, however, positively related to the duration of tenure in the current year (P < 0.0001). The overall annual return rate was 43% which is not significantly different from the survival rate for the general male population and suggests that territorial tenure does not contribute to increased mortality in male Antarctic fur seals.

Declines in large vertebrate populations are widespread but difficult to detect from monitoring data and hard to understand due to a multiplicity of plausible biological explanations. In parts of Scotland, harbour seals (Phoca vitulina) have been in decline for 10 years. To evaluate the contributions of different proximate causes (survival, fecundity, observation artefacts) to this decline, we collated behavioural, demographic and population data from one intensively studied population in part of the Moray Firth (north-east Scotland). To these, we fit a state-space model comprising age-structured dynamics and a detailed account of observation errors. After accounting for culling (estimated by our model as 14 % of total mortality), the main driver of the historical population decline was a decreasing trend in survival of young individuals combined with (previously unrecognised) low levels of pupping success. In more recent years, the model provides evidence for considerable increases in breeding success and consistently high levels of adult survival. However, breeding success remains the most volatile demographic component of the population. Forecasts from the model indicate a slow population recovery, providing cautious support for recent management measures. Such investigations of the proximate causes of population change (survival, fecundity and observation errors) provide valuable short-term support for the management of population declines, helping to focus future data collection on those ultimate causal mechanisms that are not excluded by the demographic evidence. The contribution of specific ultimate drivers (e.g. shooting mortality or competitors) can also be quantified by including them as covariates to survival or fecundity.

This research was funded by the Scottish Government (www.scotland.gov.uk), Scottish Natural Heritage (www.snh.gov.uk) and the Natural Environment Research Council (www.nerc.ac.uk). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The harbour seal population in Orkney, off the north coast of Scotland, has reduced by 65% between 2001 and 2010. The cause(s) of this decline are unknown but must affect the demographic parameters of the population. Here, satellite telemetry data were used to test the hypothesis that increased pup mortality could be a primary driver of the decline in Orkney. Pup mortality and tag failure parameters were estimated from the duration of operation of atellite tags deployed on harbour seal pups from the Orkney population (n = 4) and from another population on the west coast of Scotland (n = 24) where abundance was stable. Survival probabilities from both populations were best represented by a common gamma distribution and were not different from one another, suggesting that increased pup mortality is unlikely to be the primary agent in the Orkney population decline. The estimated probability of surviving to 6 months was 0.390 (95% CI 0.297 – 0.648) and tag failure was represented by a Gaussian distribution, with estimated mean 270 (95% CI = 198 – 288) and s.d. 21 (95% CI = 1 – 66) days. These results suggest that adult survival is the most likely proximate cause of the decline. They also demonstrate a novel technique for attaining age-specific mortality rates from telemetry data. Publisher PDF

1. For British grey seals, as with many pinniped species, population monitoring is implemented by aerial surveys of pups at breeding colonies. Scaling pup counts up to population estimates requires assumptions about population structure; this is straightforward when populations are growing exponentially, but not when growth slows, since it is unclear whether density dependence affects pup survival or fecundity. 2. We present an approximate Bayesian method for fitting pup trajectories, estimating adult population size and investigating alternative biological models. The method is equivalent to fitting a density dependent Leslie matrix model, within a Bayesian framework, but with the forms of the density dependent effects as outputs rather than assumptions. 3. This approach requires fewer assumptions than the state space models currently used, and produces similar estimates. The simplifications made the models easier to fit, reducing their computational intensity and allowing regional differences in demographic parameters to be considered. 4. The approach is not restricted to situations where only a single component of the population is observable, but, particularly in those cases, provides a practical method for extracting information from limited datasets. 5. We discuss the potential and limitations of the method and suggest that this approach provides a useful tool for at least the preliminary analysis of similar datasets. Publisher PDF

Thousands of Caspian seals (Phoca caspica) died in the Caspian Sea from April to August 2000. Lesions characteristic of morbillivirus infection were found in tissue specimens from dead seals. Canine distemper virus infection was identified by serologic examination, reverse transcriptase- polymerase chain reaction, and sequencing of selected P gene fragments. These results implicate canine distemper virus infection as the primary cause of death.

Energy expenditure of fasting territorial male Antarctic fur seals at South Georgia was measured by mass loss and analysis of carcass composition using tritium dilution in 1987 and 1988. Mean mass loss was 1.52 ± 0.04 kg • d⁻¹, mean length of territory tenure was 30.7 ± 2.21 d, mean mass at the start of tenure was 188.0 ± 1.92 kg; there were no differences between the two years (P > 0.1). Mass loss was 53.8% fat (80% of which was from blubber), 36% water, and 10.2% protein. Fat accounted for 91.6% of energy expenditure, the remainder being from protein. Energy expenditure was 42.1 ± 2.34 MJ • d⁻¹, or 3.16 ± 0.34 W • kg⁻¹, which is 3.3 times the predicted basal metabolic rate. Large body size in male compared to female fur seals may be related to the energy requirements of territoriality, but only in 1988 was there a significant correlation between starting mass and duration of tenure. This suggests that energy reserves are only one of several factors influencing tenure duration. Male fur seals are compose...

The arrival of Antarctic fur seals at a breeding beach on Bird Island, South Georgia, was studied over five consecutive breeding seasons, 1983 to 1987. Experienced bulls arrived first and established breeding territories on the beaches in anticipation of the arrival of the cows. Male arrival, which is less synchronous within years than female arrival, was significantly later in 1987 than in any other year. Female arrival, estimated by pup birth date where necessary, was highly synchronous; it usually started when 80% or more of potential territory sites were occupied by males. Cows arrived significantly later in 1984 and 1987 than in 1983, 1985 or 1986. The late arrival of both males and females in 1987 is attributed to unusually severe climatic conditions during the preceding winter. The late arrival and reduced fecundity of females in 1984 is attributed to markedly reduced food availability during the austral winter and summer of 1983. Males were not affected in 1984 because they could move away from the area of reduced food availability earlier than females and because they have a more varied diet. Factors influencing the winter distribution, the timing and pattern of arrival and the breeding of male and female Antarctic fur seals are discussed.

Adult Antarctic fur seals (Arctocephalus gazella) were immobilized with Zoletil® (n= 172), ketamine (n= 30), ketamine mixed with diazepam (n= 23) and with ketamine mixed with xylazine (n= 45). Response to all drugs was highly variable. There was a relationship between dose rate and level of immobilization in females given Zoletil®. Males were slightly more sensitive to Zoletil® than females but this could have been due to the greater body mass and lower mass-specific metabolic rate of males. The dose required to achieve a level of immobilization declined with greater body mass for Zoletil® and ketamine but not for ketamine-diatepam. Ketamine and ketamine-sedative mixtures commonly caused mild tremoring and occasionally caused convulsions. Neither reaction was seen with Zoletil®. Mean doses were, Zoletil® 1.5 mg/ kg, ketamine 6.9 mg/kg, ketamine-diazepam 6.3 mg/kg ketamine and 6.3 μg/kg diazepam, and ketamine-xylazine 7.3 mg/kg ketamine and 0.62 mg/ kg xylazine. Zoletil® performs at least as well on Antarctic fur seals as ketamine but it may cause respiratory depression. The dose of ketamine required for Antarctic fur seals was greater than for most other species of seals.

The UK holds approximately 40% of the European harbour seal population, with the majority found around the coasts of Scotland. Harbour seal populations in the UK have been monitored through a series of repeated aerial surveys of animals hauled out during the annual moult in early August. This moult count is used as a consistent index of population size. Survey methods and frequencies vary. The Scottish and English east coast populations mainly haul out in tidal estuariesand are surveyed annually, using fixed wing aircraft and digital photography. Populations in north and west Scotland often haul out on rocky shores and are surveyed less frequently, using helicopters fitted with thermal imagers. Overall, the most recent minimum estimate of the UK harbour seal population is 24,250 seals of which 19,800 are in Scotland, 3,200 in England and 1,250 in Northern Ireland. The results show that the number of harbour seals in eastern Englandwas increasing before the 1988 and 2002 phocine distemper (PDV) epizootic but has not increased since the end of the 2002 epizootic. There is also evidence of a general decline in most of the large harbour seal colonies around Scotland. The populations along the north and northwest mainland coast were an exception, with numbers appearing to be stable. Between 2001 and 2008, the population in Orkney declined by 67% and Shetland declined by 40%, indicating harbourseals in these areas experienced substantially increased mortality or very low recruitment over this period. The widespread declines, ranging from Shetland to The Wash, suggest that the causes may have been present over a large part of the North Sea and waters off western Scotland.

This research examines the energy budget of breeding female Antarctic fur seals, both when food was plentiful and when it was scarce. The energy expenditure and change in body mass of lactating female Antarctic fur seals, Arctocephalus gazella, foraging at sea was measured in two years using doubly labeled water at South Georgia Island. There was no difference between years in mass gain, water influx, mass-specific field metabolic rate (FMR), or absolute FMR. Mean at-sea FMR over both years was 9.52 ? 0.55 W/kg (n = 22), a value that is 6.7 times the predicted basal rate but only 1.9 times the FMR measured onshore. Comparable results have been reported for similar-sized northern fur seals. Krill, the nearly exclusive prey of breeding females, were very scarce in 1984 at South Georgia. Fur seal foraging trips were twice as long in 1984 as in 1985 and total mass- specific energy expended by females during these trips was significantly greater. In addition, females were significantly lighter at parturition in 1984, and both pup mortality and the proportion of pups that died from starvation were double the 1985 values. Female condition at parturition and average foraging-trip duration (i.e., offspring-pro- visioning rate) appear to reflect prey availability. The similarity between years in mass increase suggests that females do not return to feed their pups until they replenish their own reserves. Antarctic fur seal females may have a limited ability to increase the relative time spent foraging because even in normal years only 5% of their time at sea is spent resting. This contrasts with northern fur seals, Callorhinus ursinus, which typically spend 17% of their time at sea inactive. Apparently these northern seals can increase their foraging effort by increasing the proportion of time spent foraging. This would account for the observed between-year difference in at-sea FMR of C. ursinus while foraging-trip duration remained fairly constant.

Description des effets de la fertilisation naturelle des sols par les oiseaux marins sur la vegetation et comment cet enrichissement local affecte le choix de l'habitat et le succes reproducteur de Cervus elaphus