Haul-out Research Articles

Diet of the harbour sealPhoca vitulina: implication for the flatfish nursery in the Bay of Somme (English Channel, France)

Changes in marine species abundance can impact ecosystems’ stability and sustainability of fisheries. In the eastern Atlantic Ocean, harbour seals (Phoca vitulina) are top predator occupying highest trophic level in coastal marine food webs. Although, the overall European population decline, harbour seals have increased dramatically since the 1990’s at the southern limit of their European distribution along the French coast of the English Channel. However, little is known about the feeding habits of the expanding peripheral populations limiting the assessment of the role and the impact of this predator in these coastal ecosystems. Here, we investigated the sex-specific diet of harbour seals during summer in the Bay of Somme, the largest colony in the English Channel. We collected 91 faecal samples from haul-out sites mainly used by harbour seal but also by few grey seals. Molecular methods have been used to discard grey seal samples and differentiate gender. Collectively, the 86 faecal samples of harbour seals contained the remains of 3327 prey belonging to at least 13 fish species, and represented ~109 kg of consumed fish (of which 85% were soles and plaices). Most of the fish consumed were juvenile and small flatfish (Buglossidium luteum, Microchirus variegatus, Solea vulgaris, Pegusa lascaris, Pleuronectes platessa and Platichthys flesus). Hard-part identification further showed a similar diet between the sexes in terms of primary prey consumed, but a greater diversity of preys in the male diet. The dependence of harbour seals on flatfish has not been reported elsewhere and has significant implications for the sustainability of the important flatfish nursery in the Bay of Somme. Consumption estimation and ecosystem modelling are now required to provide robust assessment of the effect of harbour seal predation on population dynamics of the flatfish nursery, on ecosystem of the Bay of Biscay at-large, and finally on interactions with fisheries.

Walrus <i>Odobenus rosmarus</i> research in Svalbard, Norway, 2000-2010

Herein we report results from studies on walruses in Svalbard conducted in 2000-2010. Data from newly developed satellite relay data loggers (SRDLs) revealed seasonal differences in habitat use of adult male walruses. During winter, they moved into areas of >90% ice concentration, traveling as far as 600 km from ice-free water. Breeding areas deep into the pack ice were identified based on timing of the occupancy and diving behaviour. When the breeding season was over, walruses with SRDLs that were still transmitting locations returned to the coast, showing high site fidelity to the previous year’s summering area. Haul-out data from the SRDLs provided correction factors for an aerial survey of walruses that covered all known haul-out sites within the Svalbard Archipelago. This survey estimated 2,629 (95 % CI; 2,318 – 2,998) walruses to be in Svalbard during August 2006. Blubber biopsies from adult male walruses analyzed for fatty acids (FAs) showed vertical stratification similar to that observed in many other marine mammals. However, differences between layers were less pronounced, possibly because the thick dermis of walruses provides an insulating shield, affecting the FA composition of the outer blubber. The FA composition of the inner blubber most closely resembled the lipids in Mya truncata and Buccinum spp., which are considered the most important walrus prey in Svalbard. A study investigating the use of skin biopsies for assessing levels of organochlorines (OCs) in walruses found a significant relationship between OC levels in skin and blubber. Another contaminant study found a significant decrease in levels of PCBs and DDE in walruses in Svalbard from 1993 to 2002-04. Large inter-individual variation in OC levels was found, although all of the study animals were adult males from roughly the same location. In FA analyses of the inner blubber this variation appeared to be diet-related, with high OC levels having FA compositions in the inner blubber that closely matched seal tissues, while those with low levels matched typical invertebrate prey. Various enzymes, proteins, metabolites, minerals, and hormones were measured in blood samples to serve as baseline data for future health-related studies of both wild and captive walruses. Historical sex-distribution of walruses in southern Svalbard was investigated based on mandible measurements of individuals hunted during the 19th century.The analyses showed that female walruses were once more common in south-eastern Svalbard than they are today.

Use of Multiple Methods to Estimate Walrus (<i>Odobenus rosmarus rosmarus</i>) Abundance in the Penny Strait-Lancaster Sound and West Jones Sound Stocks, Canada

Surveys to estimate walrus abundance at terrestrial haulout sites in the Penny Strait-Lancaster Sound (PS-LS) and West Jones Sound (WJS) stocks were conducted in 1977 and 1998-2009. The Minimum Counted Population (MCP) was similar in 1977 (565) to recent years (557) for the PS-LS stock. The MCP for the WJS stock was higher in recent surveys (404) than in 1977 (290). Regression analysis of MCP and density (number of walrus divided by number of haulouts surveyed) showed no significant trends over time. We also calculated bounded count estimates for comparison. Finally, we used broad-scale behavioural data to estimate the proportion of the total stock that could be considered countable, to produce two adjusted estimates. We selected recent surveys with good coverage and ignored adjusted estimates that were lower than MCP. For the PS-LS stock, the adjusted MCP (with 95% CL) was 672 (575-768) and 727 (623-831) walrus in 2007 and 2009, respectively. For WJS, the best estimates were the adjusted MCP of 503 (473-534) in 2008 and the adjusted bounded count of 470 (297-1732) in 2009. While both stocks appear to have remained stable over three decades, differences in survey coverage and possible differences in walrus distribution make precise population estimation difficult.

Molecular epidemiology of Cryptosporidium spp. and Giardia spp. in mussels (Mytilus californianus) and California sea lions (Zalophus californianus) from Central California.

Cryptosporidium and Giardia are of public health importance, with recognized transmission through recreational waters. Therefore, both can contaminate marine waters and shellfish, with potential to infect marine mammals in nearshore ecosystems. A 2-year study was conducted to evaluate the presence of Cryptosporidium and Giardia in mussels located at two distinct coastal areas in California, namely, (i) land runoff plume sites and (ii) locations near sea lion haul-out sites, as well as in feces of California sea lions (CSL) (Zalophus californianus) by the use of direct fluorescent antibody (DFA) detection methods and PCR with sequence analysis. In this study, 961 individual mussel hemolymph samples, 54 aliquots of pooled mussel tissue, and 303 CSL fecal samples were screened. Giardia duodenalis assemblages B and D were detected in hemolymph from mussels collected near two land runoff plume sites (Santa Rosa Creek and Carmel River), and assemblages C and D were detected in hemolymph from mussels collected near a sea lion haul-out site (White Rock). These results suggest that mussels are being contaminated by protozoa carried in terrestrial runoff and/or shed in the feces of CSL. Furthermore, low numbers of oocysts and cysts morphologically similar to Cryptosporidium and Giardia, respectively, were detected in CSL fecal samples, suggesting that CSL could be a source and a host of protozoan parasites in coastal environments. The results of this study showed that Cryptosporidium and Giardia spp. from the feces of terrestrial animals and CSL can contaminate mussels and coastal environments.

Use of Haul-Out Sites by Spotted Seals (Phoca largha) on Rebun and Todojima Islands in the Japan Sea from 2008 to 2009

Use of Haul-Out Sites by Spotted Seals (<i>Phoca largha</i>) on Rebun and Todojima Islands in the Japan Sea from 2008 to 2009

Using movement data of Baltic grey seals to examine foraging-site fidelity: implications for seal-fishery conflict mitigation

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 507:297-308 (2014) - DOI: https://doi.org/10.3354/meps10846 Using movement data of Baltic grey seals to examine foraging-site fidelity: implications for seal-fishery conflict mitigation Sari M. Oksanen1,*, Markus P. Ahola2, Esa Lehtonen3, Mervi Kunnasranta1 1Department of Biology, University of Eastern Finland, PO Box 111, 80101 Joensuu, Finland 2Finnish Game and Fisheries Research Institute, Itäinen Pitkäkatu 3, 20520 Turku, Finland 3Finnish Game and Fisheries Research Institute, PO Box 2, 00791 Helsinki, Finland *Corresponding author: sari.oksanen@uef.fi ABSTRACT: Knowledge of the intensity of spatial overlap between aquatic top predators and fisheries is required to efficiently alleviate the negative effects of marine mammal-fishery interactions. We used satellite telemetry to study the movements and habitat use of Baltic grey seals Halichoerus grypus, with special focus on the degree of site fidelity to foraging and haul-out areas and spatio-temporal overlap with coastal fisheries. Most of the tracked seals (14/16 individuals) were ‘residents’, which remained within 120 ± 62 km (mean ± SD) of their capture sites during the open-water season, whereas 2 ‘transient’ seals occupied much larger areas, over 400 km from their capture sites. Residents used on average 4.3 ± 2.5 haul-out sites, indicating high haul-out site fidelity during the open-water season. Residents had active core areas (58 ± 35 km2, 50% local nearest-neighbour convex hull [LoCoH], excluding haul-out locations) near river estuaries or at other shallow water areas, indicating foraging-site fidelity to these foraging grounds. They overlapped both spatially and temporally with trap-net fishing. The high site fidelity of grey seals indicates that foraging and haul-out areas should be taken into account in population management. Selective removal of seals overlapping with fishery could be a locally focused method to mitigate seal-fishery interactions. However, removal of individuals in foraging areas may also compromise the conservation needs of the population by targeting the same animals that are hauling out in seal sanctuaries. KEY WORDS: Baltic Sea · GPS phone tag · Habitat preference · Halichoerus grypus · Home range · Seal-fishery overlap · Trap-net fishery Full text in pdf format Erratum PreviousCite this article as: Oksanen SM, Ahola MP, Lehtonen E, Kunnasranta M (2014) Using movement data of Baltic grey seals to examine foraging-site fidelity: implications for seal-fishery conflict mitigation. Mar Ecol Prog Ser 507:297-308. https://doi.org/10.3354/meps10846 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 507. Online publication date: July 17, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

A re-evaluation of the size of the white shark (Carcharodon carcharias) population off California, USA.

White sharks are highly migratory and segregate by sex, age and size. Unlike marine mammals, they neither surface to breathe nor frequent haul-out sites, hindering generation of abundance data required to estimate population size. A recent tag-recapture study used photographic identifications of white sharks at two aggregation sites to estimate abundance in “central California” at 219 mature and sub-adult individuals. They concluded this represented approximately one-half of the total abundance of mature and sub-adult sharks in the entire eastern North Pacific Ocean (ENP). This low estimate generated great concern within the conservation community, prompting petitions for governmental endangered species designations. We critically examine that study and find violations of model assumptions that, when considered in total, lead to population underestimates. We also use a Bayesian mixture model to demonstrate that the inclusion of transient sharks, characteristic of white shark aggregation sites, would substantially increase abundance estimates for the adults and sub-adults in the surveyed sub-population. Using a dataset obtained from the same sampling locations and widely accepted demographic methodology, our analysis indicates a minimum all-life stages population size of >2000 individuals in the California subpopulation is required to account for the number and size range of individual sharks observed at the two sampled sites. Even accounting for methodological and conceptual biases, an extrapolation of these data to estimate the white shark population size throughout the ENP is inappropriate. The true ENP white shark population size is likely several-fold greater as both our study and the original published estimate exclude non-aggregating sharks and those that independently aggregate at other important ENP sites. Accurately estimating the central California and ENP white shark population size requires methodologies that account for biases introduced by sampling a limited number of sites and that account for all life history stages across the species' range of habitats.

INCREASEDCONTRACAECUM OSCULATUMINFECTION IN BALTIC COD (GADUS MORHUA) LIVERS (1982–2012) ASSOCIATED WITH INCREASING GREY SEAL (HALICHOERUS GRYPHUS) POPULATIONS

Grey seals (Halichoerus gryphus), the main final host of the gastric parasitic nematode Contracaecum osculatum in the Baltic, have recently recolonized the southwestern Baltic Sea. This colonization could lead to an increase in prevalence and intensity of third-stage larvae of C. osculatum in livers of Baltic cod (Gadus morhua), which serve as transport host for this helminth. We performed a parasitologic study of cod in spring 2012 and compared the results with previously unpublished data from 1982/1983. Additionally, grey seals were counted annually from 2000 to 2011 at three haul-out sites in the southwestern Baltic. Of 97 cod livers examined in the 1982/1983 survey, 22% harbored C. osculatum larvae, whereas 55.1% of the examined cod livers (n=185) were infected in 2012; the mean intensity and mean abundance increased from 4.3 and 0.9 to 20.2 and 11.1, respectively. Molecular identification (PCR) confirmed the identity of the larvae. The grey seal population increased markedly during the 12-yr period. We suggest that the elevated parasitism of cod livers is associated with the successful re-establishment of grey seals in the southwestern Baltic.

Fine-Scale Variability in Harbor Seal Foraging Behavior

Understanding the variability of foraging behavior within a population of predators is important for determining their role in the ecosystem and how they may respond to future ecosystem changes. However, such variability has seldom been studied in harbor seals on a fine spatial scale (<30 km). We used a combination of standard and Bayesian generalized linear mixed models to explore how environmental variables influenced the dive behavior of harbor seals. Time-depth recorders were deployed on harbor seals from two haul-out sites in the Salish Sea in 2007 (n = 18) and 2008 (n = 11). Three behavioral bout types were classified from six dive types within each bout; however, one of these bout types was related to haul-out activity and was excluded from analyses. Deep foraging bouts (Type I) were the predominant type used throughout the study; however, variation in the use of bout types was observed relative to haul-out site, season, sex, and light (day/night). The proportional use of Type I and Type II (shallow foraging/traveling) bouts differed dramatically between haul-out sites, seasons, sexes, and whether it was day or night; individual variability between seals also contributed to the observed differences. We hypothesize that this variation in dive behavior was related to habitat or prey specialization by seals from different haul-out sites, or individual variability between seals in the study area. The results highlight the potential influence of habitat and specialization on the foraging behavior of harbor seals, and may help explain the variability in diet that is observed between different haul-out site groups in this population.

Population trends of the Kuril harbour seal Phoca vitulina stejnegeri from 1974 to 2010 in southeastern Hokkaido, Japan

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 24:61-72 (2014) - DOI: https://doi.org/10.3354/esr00553 Population trends of the Kuril harbour seal Phoca vitulina stejnegeri from 1974 to 2010 in southeastern Hokkaido, Japan Yumi Kobayashi1,*, Tatsuya Kariya2, Jun Chishima2, Kei Fujii2, Kazuo Wada3, Shinya Baba1, Tetsuro Itoo4,†, Toshiyasu Nakaoka5, Miki Kawashima2, Sachiko Saito2, Noriyuki Aoki6, Shin-ichi Hayama7, Yuichi Osa8, Hidemi Osada2, Akio Niizuma9,†, Masatsugu Suzuki10, Yohjiro Uekane2,†, Kei Hayashi11, Mari Kobayashi12,13, Noriyuki Ohtaishi14, Yasunori Sakurai1 1Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido 041-8611, Japan 2Pinniped Research Group, Sapporo, Hokkaido 005-0018, Japan 3Primate Research Institute of Kyoto University, Inuyama, Aichi 484-8506, Japan 4North Pacific Pinniped Research Association, Gifu 501-1193, Japan 5Erimo Town Museum, Erimo, Hokkaido 058-0203, Japan 6Japanese Bird Banding Association, Nemuro, Hokkaido, 087-0036, Japan 7Center for Wildlife Conservation and Management, Nippon Veterinary and Animal Science University, Tokyo 180-8602, Japan 8Environmental and Geological Research Department, Institute of Environmental Sciences, Hokkaido Research Organization, Kushiro, Hokkaido 085-8588, Japan 9Faculty of Human and Social Studies, Keisen University, Tokyo 206-8586, Japan 10Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan 11Kuril Harbour Seal Research Group, Obihirio University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-0835, Japan 12Department of Aqua-Bioscience and Industry, Faculty of Bioindustry, Tokyo University of Agriculture, Abashiri, Hokkaido 099-2493 Japan 13Marine Wildlife Center of Japan, Incorporated Non Profit Organization, Abashiri, Hokkaido 093-0042, Japan 14The Hokkaido University Museum, Sapporo, Hokkaido 060-0812, Japan *Corresponding author: kobayumi_kotomasu@hotmail.com †Deceased ABSTRACT: The Kuril harbour seal Phoca vitulina stejnegeri is an endangered species which inhabits southeastern Hokkaido, Japan. Its population declined precipitously from between 1500 and 4800 individuals in the 1940s to a few hundred individuals in the early 1970s. The causes of this decline are thought to be commercial harvesting, bycatch in autumn set-net salmon fishing, and other human activities, including coastal fisheries. To quantify Kuril seal population trends, counts were performed each year at haul-out sites during the pupping season from 1974 to 2010 and during the moulting season from 1983 to 2010. The average population growth rate was ~4% per annum over the past 37 yr. Two haul-out sites (Kenbokki Island and Hattaushi) from which the species had disappeared in the early 1980s showed no evidence of being recolonized. Commercial harvesting ended in the late 1980s and probably had an effect on population trends until the 1990s. The bycatch of seals during autumn set-net salmon fishing in the 2000s remained similar to, or slightly greater than, that during the 1980s. Recently, seals have been observed at 9 haul-out sites during the pupping/moulting season along the coast of southeastern Hokkaido. Approximately 70% of the seals found were at Cape Erimo (~500 seals) and at Daikoku Island and Akkeshi (~250 seals). KEY WORDS: Population counts · Bayesian state-space models · Conservation · Pinnipeds · Endangered species · Japan Full text in pdf format Supplementary material PreviousNextCite this article as: Kobayashi Y, Kariya T, Chishima J, Fujii K and others (2014) Population trends of the Kuril harbour seal Phoca vitulina stejnegeri from 1974 to 2010 in southeastern Hokkaido, Japan. Endang Species Res 24:61-72. https://doi.org/10.3354/esr00553 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 24, No. 1. Online publication date: April 09, 2014 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2014 Inter-Research.

Walruses recovering after 60+ years of protection in Svalbard, Norway

Walruses were brought to the brink of extinction in Svalbard (Norway) during 350 years of unregulated harvesting. They became protected in 1952, when few remained. During the first 30 years of protection, approximately 100 animals became established within the archipelago, most of which likely came from Franz Josef Land, to the east. A marked recovery has taken place since then. This study reports the results of a photographic aerial survey flown in summer 2012, covering all current and historical haul-out sites for walruses in Svalbard. It provides updates regarding the increasing numbers of: (1) land-based haul-out sites (from 78 in 2006 to 91 in 2012); (2) occupied sites (from 17 in 2006 to 24 in the 2012 survey); (3) sites with mother–calf pairs (which increased from a single site with a single small calf in 2006 to 10 sites with a total of 57 small calves in 2012) and; (4) a 48% increase in abundance in the six-year period between the two surveys to 3886 (confidence interval 3553–4262) animals, including animals in the water at the time of the survey. Future environmental change might reduce benthic production in the Arctic, reducing the prey-base for walruses, and also impact walruses directly via declines in their sea-ice breeding habitat. But, currently the Svalbard walrus population is growing at a rate that matches the theoretical maximum rate of growth that has been calculated for recovering walrus populations under favourable environmental conditions with no food limitations.Keywords: Arctic; expansion; mother–calf distribution; pinniped; population trend.(Published: 7 October 2014)Citation: Polar Research 2014, 33, 26034, http://dx.doi.org/10.3402/polar.v33.26034

Changes in the abundance and distribution of the New Zealand fur seal (Arctocephalus forsteri) in Western Australia: are they approaching carrying capacity?

New Zealand fur seals have been increasing in abundance across Australia over the past 20 years, with annual population growth rates of 10–15%. Recent changes in distribution in Western Australia suggested that the population was increasing and expanding in range beyond the known historical distribution. We aimed to determine the growth rate of individual colonies and the overall population across Western Australia and identify new breeding and haulout sites. We used the direct count technique to estimate New Zealand fur seal pup production at 17 breeding sites. We estimated pup production to be 3518 in the 2010/11 austral summer, producing a resultant population estimate of ~17 200 New Zealand fur seals in Western Australia. This represented an exponential growth rate over the past 12 years of ~1% per annum, a significant reduction from the estimated rate of 10% per annum between 1989 and 1999. There were clusters of colonies that showed large annual declines of 6–7% in pup production over the past 12 years and at other colonies maximal rates of increase of pup production were 6–9% per annum. Three new breeding colonies were discovered. It appears that the New Zealand fur seal population is nearing its carrying capacity in Western Australia.

The influence of ice conditions on terrestrial haulouts of the pacific walrus Odobenus rosmarus divergens Illiger, 1815 in the Gulf of Anadyr, Bering Sea

The boundaries of the area of appropriate depths for feeding by the Pacific walrus were determined. Based on the ice maps for the period of 1997–2011, the long-term dynamics of ice breakup and formation in the Gulf of Anadyr (Bering Sea) were analyzed. There was a tendency towards a reduction in the ice-cover period in the Gulf of Anadyr, especially during 2007–2011. In 2008, the number and duration of stay of walruses at terrestrial haulout sites on Meeskyn Spit Island and on Retkyn Spit continued to decrease. Walruses also used other haulouts located in the Gulf of Anadyr at Cape Gek and Cape Retkyn. The age and sex structure of the walrus herd changed: the proportions of adult males and young animals decreased, while the proportion of females with calves increased.

Prey switching by killer whales in the north-east Atlantic: observational evidence and experimental insights

Studies in the Pacific have identified distinct killer whale ecotypes that are either specialized mammal- or fish-eaters. The different types have developed hunting strategies that would suggest specialization could be more advantageous than generalism. However, it has been suggested, based on long-term dietary markers of tooth wear and stable isotope values, that lineages in the North Atlantic are generalist, but with individual variation in the proportion of prey types consumed. Here, we present the results of ten years of observational and photo-identification data of a population of killer whales that follows the Norwegian spring-spawning stock of Atlantic herring. Although the whales were predominantly observed while feeding upon herring, one pod of herring-eating whales was also observed interacting with seals. This supports the hypothesis based on the long-term markers, of a degree of specialization, with a small number of groups persistently feeding upon mammals, but switching between herring and seals. We further investigated this prey switching by conducting playbacks of herring-eating killer whale sounds to harbour seals at haul-out sites on the herring spawning grounds. We recorded changes in behaviour consistent with an anti-predator response, suggesting the seals perceived the herring-eating killer whales as a potential predatory threat and had not habituated to their calls. This could be due to the risk of herring-eating killer whales switching to mammalian prey, or the difficulty of discriminating between killer whale pods due to the large population size and number of killer whale call dialects in this population, or a combination of both.

Modelling harbour seal habitat by combining data from multiple tracking systems

Technological developments over the last 20years have meant that telemetry studies have used a variety of techniques, each with different levels of accuracy and temporal resolution. This presents a challenge when combining data from these different tracking systems to obtain larger sample sizes or to compare habitat use over time. In this study, we used a Bayesian state-space modelling approach to integrate tracking data from multiple tag types and standardise position estimates while accounting for location error. Harbour seal (Phoca vitulina) telemetry data for the Moray Firth, Scotland, were collated from three tag types: VHF, Argos satellite and GPS–GSM. Tags were deployed on 37 seals during 1989 to 2009 resulting in 37 tracks with a total of 2886 tracking days and a mean duration of 87days per track. A state-space model was applied to all of the raw tracks to provide daily position estimates and a measure of the uncertainty for each position. We used this standardised tracking dataset to model their habitat use and preference, which was then scaled by the population size estimated from haul-out counts to give an estimate of the absolute number of harbour seals using different parts of the Moray Firth. As expected for a central place forager, harbour seals most frequently occurred in areas close to their inshore haul-out sites. However, our analyses also demonstrated consistent use of offshore foraging grounds, typically within 30km of haul-out sites in waters <50m deep. The use of these statistical models to integrate and compare different datasets is especially important for assessing longer-term responses to environmental variation and anthropogenic activities, allowing management advice to be based upon datasets that integrate information from all available tracking technologies.

Haulout patterns of Saimaa ringed seals and their response to boat traffic during the moulting season

Conservation of the Critically Endangered ringed seal Phoca hispida saimensis pop- ulation in Lake Saimaa in Finland requires broader knowledge of the behavioural ecology of this subspecies. Understanding Saimaa ringed seal haulout patterns and their response to boat traffic is crucial for designing sustainable land use and tourism guidelines. Responses of unidentified seals to small outboard motor boat traffic were studied during the moulting season. The median distance at which the seals responded to an approaching boat was 240 m. GPS-phone tags were used to study both circadian and seasonal haulout behaviour patterns of individual seals (n = 8) during the open-water season. The average post-moulting haulout duration was 6 ± 5 h (SD), with a maximum of over 26 h. The seals spent more time hauled out at night (between 21:00 and 06:00 h) after the moult. The time spent hauled out and the haulout frequency declined from early summer to autumn. An individual seal had an average of 13 haulout sites, which were an average of 2.5 km apart. Approximately half of these haulout sites were located in the core 50% of the indi- vidual seals' home ranges. The high level of site fidelity emphasizes the need to identify suitable haulout areas and to develop measures for protecting the main resting sites of this endangered population. Additionally, guidelines for seal watching should be developed in order to mitigate the potential disturbance caused by increasing tourism on Lake Saimaa.

Status of the harbour seal (&lt;i&gt;Phoca vitulina&lt;/i&gt;) in Southern Scandinavia

The harbour seal population in Southern Scandinavia has experienced repeated declines caused by hunting and epizootics. These events have shaped the current distribution and abundance of the population. This paper assesses the current status of the population. We estimate trends in abundance of harbour seals from long term survey data, compare these with historic trends inferred from previously published material, and discuss past and potential threats to the harbour seal population of Southern Scandinavia. It is evident that harbour seals have disappeared from haulout areas along the Danish shores of Kattegat and in the westernmost part of the Baltic Sea, where they were previously numerous. In the 1920-30s, when abundance was at its lowest, the population is estimated to have been only a fraction of its original size. Following 30 years of protection the population is currently approaching historic abundance and might have reached the carrying capacity in some areas. Further development depends largely on effects of future epizootics, anthropogenic disturbance, and availability of suitable haulout sites.

Faecal DNA amplification in Pacific walruses (Odobenus rosmarus divergens)

Dietary information is critical for assessing the population status of seals, sea lions and walruses—and is determined for most species of pinnipeds using non-inva- sive methods. However, diets of walruses continue to be described from the stomach contents of dead individuals. Our goal was to assess whether DNA could be extracted from the faeces of Pacific walruses (Odobenus rosmarus divergens) collected at haulout sites, and whether potential prey species or taxa could be amplified from that DNA. We extracted DNA from 70 faecal samples collected from ice pans in the Bering Sea during the spring of 2008 and 2009 (with between 4.6 and 308.9 ng/ll of DNA in every sam- ple). We also extracted DNA from 12 potential prey spe- cies or taxa collected by bottom-grabs in 2009 to identify positive controls for primers and to test the ability of pre- viously published taxon-specific and species-specific primers to correctly identify the prey using conventional PCR. We tested primers that successfully amplified DNA from the tissue of at least one potential prey species or taxon on all 70 walrus faecal samples. We found that two sets of primers successfully amplified many of the potential prey species or taxa using DNA from their tissue, and that one of these primer sets produced positive amplification in 4 of the 70 faecal samples. The band size that was pro- duced for prey organisms and in the faecal samples was consistent with expectations, although prey identities were not verified with sequencing. Our pilot study demonstrates that DNA can be successfully extracted and amplified from walrus faeces, providing a stepping stone towards describing the diets of walruses from faecal DNA.

Food Habits of Harbor Seals (Phoca vitulina) in Two Estuaries in the Central Salish Sea

This study describes the seasonal diet composition of the Pacific harbor seal (Phoca vitulina) in two estuaries, Padilla Bay and Drayton Harbor, in the central Salish Sea. Prey remains were recovered from harbor seal fecal samples (scats) collected at haul-out sites during spring and summer/ fall in 2006. Top prey taxa (≥ 25% frequency of occurrence) were compared between seasons, estuaries, and between estuarine and non-estuarine haul-out sites. Overall, prey from at least 26 taxonomic families were identified in 198 harbor seal scats. In Padilla Bay, the most common prey were gunnel (family Pholidae; 88.6%), snake prickleback (Lumpenus sagitta; 59.1%), Pacific staghorn sculpin (Leptocottus armatus; 50.0%), and shiner perch (Cymatogaster aggregata; 47.7%). Threespine stickleback (Gasterosteus aculeatus; 95.5%) and Pacific herring (Clupea pallasi; 83.1%) were the most frequently consumed species in Drayton Harbor; shiner perch, snake prickleback, mammal, and Pacific staghorn sculpin also each occurred in ≥ 50% of samples from at least one season. Occurrences of top prey taxa varied by season, estuary, and habitat type. Diet composition suggests that harbor seals in Padilla Bay and Drayton Harbor foraged primarily within estuarine habitats such as those found near the haul-out sites. Temporal and spatial variations in diet appeared to reflect differences in the availability of prey taxa. This study also identifies mammals as a potentially novel prey item for harbor seals in Drayton Harbor.

Causes and Patterns of Harbor Seal (Phoca vitulina) Pup Mortality at Smith Island, Washington, 2004–2010

Harbor Seals (Phoca vitulina) are the most common and widely distributed pinniped in Washington State coastal waters. Serving as sentinels of marine ecosystem health, stranded animals are useful in detecting environmental disease and contaminant levels. From 2004 to 2010, we examined mortality rates and causes of death of Harbor Seal pups at Smith Island, a principal haulout site in the eastern Strait of Juan de Fuca, Washington, conducting 21 site surveys during the pupping season (June through August). We documented and externally examined 245 dead pups and of these, 72 were deemed suitable for more detailed internal examination and were collected for necropsy to determine cause of death. Minimum estimated neonatal mortality varied widely by year and ranged from 3 to 25%. The highest number of dead pups, nearly half of the total for the study, were found in 2005; this was also the year with the highest estimate of pups born and highest proportion of pups born that were documented dying. Infection was the leading primary cause of death in most years including 2005, when 40% of the pups died from an infectious process. The 2nd leading cause of death was malnutrition; other causes included prematurity and dystocia. This study documents some of the major annual differences that can occur in both mortality rates and causes of death in Harbor Seals.