Haul-out Behaviour Research Articles

Factors influencing haulout behaviour of non-breeding weddell seals (Leptonychotes weddellii) at Cape Royds, Antarctica

The Weddell seal (Leptonychotes weddellii) is a fast-ice obligate species that plays an important role as both predator and prey within the high-latitude, coastal Southern Ocean. Weddell seals are affected by pressures of marine resource extraction and variation in sea-ice extent and characteristics that are affected by climate. Thus, monitoring their population dynamics provides an indicator of the effectiveness of fisheries management, and impacts of changing climate in the high latitude Southern Ocean ecosystem. Satellite imagery is increasingly being used to monitor the populations of this species, but assessment techniques require a better understanding of the environmental factors influencing the likelihood that individuals will be on the sea-ice and therefore visible in a satellite image. Addressing that goal, we captured 5054 trail camera photos during spring 2017 in the 24-h light at Cape Royds, Antarctica, and then counted seals on the fast ice every 30 min over 59 days. Using a generalised additive model (63% deviance explained) we described the haulout behaviour of non-breeding Weddell seals according to time of day, date, air temperature, pressure, solar radiation, and wind speed. We found that the seals’ haulout cycle is driven to a significant degree by weather variables, primarily temperature and wind speed. Quantifying these haulout patterns can be used to determine the time of day, and under what conditions, that most seals are hauled out. Integrating environmental parameters to correct time-of-day patterns would allow better cross-site abundance comparisons, leading to better Weddell seal population estimates for the Ross Sea region and the wider coastal Antarctica.

Assessing the Impact of Transportation on Seal Behaviour: A Case Study from Ísafjörður, Iceland.

This study explores the behavioural responses of seals to various disturbances while hauling out within a transport hub featuring diverse transport facilities. Utilising Factor Analysis of Mixed Data (FAMD) on observations from September 2021 to May 2023 in Ísafjörður, Iceland, the research reveals that watercraft, particularly kayaks, significantly affect seal haul-out behaviour, triggering vigilance and flush responses. Aerial vehicles also induce stress responses, whereas road-based vehicles have lower impacts. These findings highlight the substantial influence of human activities, especially transportation, on seal haul-out behaviour, suggesting a need for mitigating strategies to reduce these impacts.

Haulout Patterns of Harbour Seal Colonies in the Norwegian Skagerrak, as Monitored through Time-Lapse Camera Surveys

Harbour seals (Phoca vitulina) are part of the Norwegian coastal ecosystem and can be observed on skerries, islands, and sandbanks along the coastline, sometimes in close proximity to inhabited areas. In this study, we used time-lapse camera surveys to monitor the haulout patterns of harbour seals at two selected sites in the Norwegian Skagerrak, Lyngør and Østre Bolæren, over 12 and 4 months, respectively. The goal was to investigate how the number of seals hauling out on land varied seasonally and how it was influenced by environmental parameters (wind speed, air temperature, and water level), the time of the day, and anthropogenic disturbances. As expected, the number of seals hauled out increased with increasing air temperature and decreased with increasing wind speed and water level. Clear circadian patterns in the seal haulout behaviour were identified during autumn and winter when a significantly higher number of seals were observed on land at night. Moreover, haulout patterns showed significant seasonal variation, with a peak in haul outs being observed during the moulting season in August. Despite an expected high usage of land during the breeding season in early summer, the number of seals hauled out at the Lyngor study site was low during this period, especially during weekends and summer holidays, maybe due to increased disturbance from boats. This study provides valuable insights into the factors influencing the haulout behaviour of the species in the region and suggests possible effects of human disturbance on harbour seal behaviour in the area.

Spring haul-out behavior of seals in the Bering and Chukchi Seas: implications for abundance estimation.

Ice-associated seals rely on sea ice for a variety of activities, including pupping, breeding, molting, and resting. In the Arctic, many of these activities occur in spring (April through June) as sea ice begins to melt and retreat northward. Rapid acceleration of climate change in Arctic ecosystems is therefore of concern as the quantity and quality of suitable habitat is forecast to decrease. Robust estimates of seal population abundance are needed to properly monitor the impacts of these changes over time. Aerial surveys of seals on ice are an efficient method for counting seals but must be paired with estimates of the proportion of seals out of the water to derive population abundance. In this paper, we use hourly percent-dry data from satellite-linked bio-loggers deployed between 2005 and 2021 to quantify the proportion of seals hauled out on ice. This information is needed to accurately estimate abundance from aerial survey counts of ice-associated seals (i.e., to correct for the proportion of animals that are in the water, and so are not counted, while surveys are conducted). In addition to providing essential data for survey 'availability' calculations, our analysis also provides insights into the seasonal timing and environmental factors affecting haul-out behavior by ice-associated seals. We specifically focused on bearded (Erignathus barbatus), ribbon (Histriophoca fasciata), and spotted seals (Phoca largha) in the Bering and Chukchi seas. Because ringed seals (Phoca (pusa) hispida) can be out of the water but hidden from view in snow lairs analysis of their 'availability' to surveys requires special consideration; therefore, they were not included in this analysis. Using generalized linear mixed pseudo-models to properly account for temporal autocorrelation, we fit models with covariates of interest (e.g., day-of-year, solar hour, age and sex class, wind speed, barometric pressure, temperature, precipitation) to examine their ability to explain variation in haul-out probability. We found evidence for strong diel and within-season patterns in haul-out behavior, as well as strong weather effects (particularly wind and temperature). In general, seals were more likely to haul out on ice in the middle of the day and when wind speed was low and temperatures were higher. Haul-out probability increased through March and April, peaking in May and early June before declining again. The timing and frequency of haul-out events also varied based on species and age-sex class. For ribbon and spotted seals, models with year effects were highly supported, indicating that the timing and magnitude of haul-out behavior varied among years. However, we did not find broad evidence that haul-out timing was linked to annual sea-ice extent. Our analysis emphasizes the importance of accounting for seasonal and temporal variation in haul-out behavior, as well as associated environmental covariates, when interpreting the number of seals counted in aerial surveys.

Effects of anthropogenic noise on haul-out numbers of harbor seals (Phoca vitulina)

Haul-out sites of harbor seals, Phoca vitulina Linnaeus, 1758, include areas with high levels of anthropogenic noise. In some cases, seals haul out at night when there are lower in-air noise levels. However, it is unclear whether there are additional responses to noise pollution. To determine potential impacts of anthropogenic noise on haul-out behavior, we compared numbers of hauled-out harbor seals relative to in-air noise levels at two sites in Washington state, USA—one close to human activities (Bellingham waterfront) and one more distant (Semiahmoo marina)—between July 2020 and August 2021. We used generalized linear mixed models to identify predictors of seal numbers. The marina had lower mean noise levels than the waterfront (39.7 ± SD 6.1 dB, n = 29 observations versus 51.2 ± SD 5.2 dB, n = 126 observations). The plotted model prediction showed a significantly negative association between noise and seals at the marina, and no association was found at the waterfront. Results indicate that in-air noise levels may influence seal numbers at sites where human activities are low. They also suggest that, besides hauling out at night, seals may become tolerant to in-air noise levels at sites where human activities are high.

The nightlife of a Ross seal: diving and haul-out behaviour from the eastern Weddell Sea

AbstractRoss seals (Ommatophoca rossii) travel away from the pack ice and spend most of their year foraging pelagically. Here, we augment the few existing records of Ross seal diving and haul-out behaviour, providing novel insights into how these are influenced diurnally and seasonally. We used biologging devices that recorded the dive behaviour (n = 5) and/or haul-out behaviour (n = 9) of Ross seals in the eastern Weddell Sea (2016–2019). Ross seals mostly dived between 100 and 200 m deep, often > 300 m, and for 5–12 min in duration, often > 20 min. During March–July, when Ross seals forage pelagically, diving metrics varied diurnally. The seals dived deeper during twilight and shallowest at night, while the number of dives and diving duration did not follow a clear diurnal pattern. Consequently, diving effort was highest during the night. Ross seals preferentially hauled out in the middle of the day during September, October, February and December, but not during the rest of the year. Three females that entered the pack ice during breeding season were hauled out continuously for 5–7 days, punctuated by water entries for 1–3 h during and/or after such continuous haul-outs over the breeding season. This behaviour might suggest that Ross seals alternate between capital and facultative income breeding.

Bearded seals in the Atlantic Arctic: review of post 2010 knowledge available for informing stock assessments

The last extensive (pan-Arctic) review on knowledge available on the bearded seal (Erignathus barbatus) was conducted by Cameron et al. in 2010. As bearded seals are hunted off Svalbard and Greenland but no stock assessments are available, NAMMCO requested a status review, and if possible, an assessment of the species in its area. This literature review attempts to summarise the knowledge that has become available post 2010, with a focus on the Atlantic Arctic. A large amount of information has become available on the behaviour of the bearded seal, with hearing, vocalisation, haul-out behaviour and movement patterns (through satelitte tagging), and their phenology, being well studied. A database of baseline blood parameters is slowly being built but is still limited. New data on distribution has emerged from PAM studies and non-targeted surveys. Abundance estimates are missing for Svalbard, but partial estimates have become available for the North Water Polynya in 2009 and 2014. Additionally, observations of bearded seals from aerial line-transect surveys are available for several areas of Greenland but have not been analysed. More information has become available on the impact of anthropogenic stressors, such as climate change and other related environmental changes, although demographic impacts of changes are missing. Catch data exists for both Svalbard and Greenland, but for the latter the data needs to be thoroughly validated. In summary, information on stock structure as well as local and global abundance estimates, which are both important to assess the sustainability of current catches, are still missing. However other lines of evidence can inform the delineation of management areas and the results of a pan-arctic genetic study should become available shortly. There is survey data available from Greenland that could be used to generate local abundance estimates, the analysis of which should be prioritised.

So happy together: juvenile crabeater seal behavior improves lice transmission.

Lice from family Echinophthiriidae are of the few insects that have successfully colonized marine environment living as ectoparasites of pinnipeds, i.e., sea lions, seals, and the walrus. They have developed unique adaptations to cope with the amphibious lifestyle of their hosts. Because eggs do not survive underwater, lice could only reproduce when their host remains on pack ice enough time. Consequently, lice generations per year are limited by host haul-out behavior. The objective of this work is to study the effect of host sex and age class, and the annual variation on the prevalence and mean abundance of Antarctophthirus lobodontis in crabeater seals from the Antarctic Peninsula. During three consecutive field-seasons, we collected lice from 41 crabeater seals (23 females, 16 males, 2 indeterminate, being 24 adults, and 17 juveniles). We investigated this effect on the prevalence and mean abundance by a generalized linear model formulation in a Bayesian framework. According to the lowest Deviance Index Criterion model, sex host does not affect prevalence nor mean abundance. We found that juveniles present greater abundance and prevalence than adults, possibly due to foraging habits. They spent more time on the ice than adults in groups of dozens of animals. This behavior would favor both egg development and lice transmission. We do not find adult females with lice, which suggests that transmission of A. lobodontis should be horizontal. The high mean abundance of lice in 2014 could be associated with an unusual increase in Lobodon carcinophaga population, probably related to the pack-ice availability and zooplankton abundance.

Ringed seal (Pusa hispida) seasonal movements, diving, and haul-out behavior in the Beaufort, Chukchi, and Bering Seas (2011-2017).

Continued Arctic warming and sea‐ice loss will have important implications for the conservation of ringed seals, a highly ice‐dependent species. A better understanding of their spatial ecology will help characterize emerging ecological trends and inform management decisions. We deployed satellite transmitters on ringed seals in the summers of 2011, 2014, and 2016 near Utqiaġvik (formerly Barrow), Alaska, to monitor their movements, diving, and haul‐out behavior. We present analyses of tracking and dive data provided by 17 seals that were tracked until at least January of the following year. Seals mostly ranged north of Utqiaġvik in the Beaufort and Chukchi Seas during summer before moving into the southern Chukchi and Bering Seas during winter. In all seasons, ringed seals occupied a diversity of habitats and spatial distributions, from near shore and localized, to far offshore and wide‐ranging in drifting sea ice. Continental shelf waters were occupied for >96% of tracking days, during which repetitive diving (suggestive of foraging) primarily to the seafloor was the most frequent activity. From mid‐summer to early fall, 12 seals made ~1‐week forays off‐shelf to the deep Arctic Basin, most reaching the retreating pack‐ice, where they spent most of their time hauled out. Diel activity patterns suggested greater allocation of foraging efforts to midday hours. Haul‐out patterns were complementary, occurring mostly at night until April‐May when midday hours were preferred. Ringed seals captured in 2011—concurrent with an unusual mortality event that affected all ice‐seal species—differed morphologically and behaviorally from seals captured in other years. Speculations about the physiology of molting and its role in energetics, habitat use, and behavior are discussed; along with possible evidence of purported ringed seal ecotypes.

Post‐disturbance haulout behaviour of harbour seals

Abstract The impact of anthropogenic activity associated with marine renewable developments on harbour seals (Phoca vitulina) was investigated using controlled disturbance trials. Hauled‐out seals were approached by boat until all seals had entered the water, and this was repeated approximately every 3 days (weather permitting). The time taken for seal counts to return to pre‐disturbance levels was determined by monitoring haulout sites using time‐lapse photography. Mean post‐disturbance counts of hauled‐out seals returned to 52% (95% confidence interval [CI] 35–69%) of pre‐disturbance counts within 30 min. However, mean counts only returned to 94% (95% CI 55–132%) of pre‐disturbance counts after 4 hr. Eight seals were tagged with Global Positioning System phone tags to provide information on haulout location and at‐sea movements, allowing investigation of how disturbance may influence haulout site choice and seal distribution. Telemetry‐tagged seals displayed a high degree of haulout site fidelity. Disturbance trials did not have a significant effect on the probability of seals moving to a different haulout site. When seals hauled out again within the same low‐tide period after disturbance trials, the proportion of time spent hauled out was high, indicating that when seals are motivated to haul out they will do so despite past disturbance. Motivation to haul out more on disturbance trial days was not linked to a cyclic pattern of hauling out more over consecutive low‐tide periods. As there was no large‐scale redistribution after disturbance, we suggest that monitoring effort to determine the effects of short‐term increases in levels of disturbance caused by boat activity can be spatially localized. However, where disturbance is likely to be longer term or impact on important haulout sites for breeding and/or moulting, monitoring may be required over a larger geographical area.

Seasonal and diel differences in dive and haul-out behavior of adult and subadult ringed seals (Pusa hispida) in the Bering and Chukchi seas

Changing environmental conditions in the Pacific Arctic are expected to affect ice-adapted marine food webs. As such, understanding ringed seal (Pusa hispida) dive and haul-out behavior is vital to understanding if and how these environmental changes affect seal foraging behavior. Working with Alaska Native subsistence hunters, we tagged 14 adult and 20 subadult ringed seals with satellite-linked data recorders in Kotzebue Sound, Alaska, during late-September and October 2007–2009. Information about dive and haul-out behavior in the Bering and Chukchi seas was collected for 12–297 days. We analyzed indices of dive depth, duration, and rate, and haul-out probability using a model selection framework for adults during fall (late-September–November) and winter (December–March) and for subadults during fall, winter, and also spring (April–June). We found differences by season and time of day, but not by sex. Where subadults and adults occurred together, they dove to similar depths; although subadults were commonly located in deeper waters where they generally dove deeper than adults. Both age classes dove longer during winter and subadults tended to make a few more (~3.5) dives per hour than adults. Both age classes hauled out less and dove deeper, longer, and more frequently during midday than at other times of day. We suspect that seals dive deeper during midday because their prey migrates deeper. Dive and haul-out behaviors of ringed seals are influenced by a combination of factors, including prey distribution and abundance, sea ice, and seal diving physiology.

Seal Occurrence and Habitat Use during Summer in Petermann Fjord, Northwestern Greenland

Ice-associated seals are considered especially susceptible and are potentially the first to modify distribution and habitat use in response to physical changes associated with the changing climate. Petermann Glacier, part of a unique ice-tongue fjord environment in a rarely studied region of northwestern Greenland, lost substantial sections of its ice tongue during major 2010 and 2012 calving events. As a result, changes in seal habitat may have occurred. Seal occurrence and distribution data were collected in Petermann Fjord and adjacent Nares Strait region over 27 days (2 to 28 August) during the multidisciplinary scientific Petermann 2015 Expedition on the icebreaker Oden. During 239.4 hours of dedicated observation effort, a total of 312 individuals were recorded, representing four species: bearded seal (Erignathus barbatus), hooded seal (Crystophora cristata), harp seal (Pagophilus groenlandicus), and ringed seal (Pusa hispida). Ringed seals were recorded significantly more than the other species (χ2 = 347.4, df = 3, p < 0.001, n = 307). We found significant differences between species in haul-out (resting on ice) behavior (χ2 = 133.1, df = 3, p < 0.001, n = 307). Bearded seals were more frequently hauled out (73.1% n = 49), whereas ringed seals were almost exclusively in water (93.9%, n = 200). Differences in average depth and ice coverage where species occurred were also significant: harp seals and bearded seals were found in deeper water and areas of greater ice coverage (harp seals: 663 ± 366 m and 65 ± 14% ice cover; bearded seals: 598 ± 259 m and 50 ± 21% ice cover), while hooded seals and ringed seals were found in shallower water with lower ice coverage (hooded seals: 490 ± 163 m and 38 ± 19% ice cover; ringed seals: 496 ± 235 m, and 21 ± 20% ice cover). Our study provides an initial look at how High Arctic seals use the rapidly changing Petermann Fjord and how physical variables influence their distribution in one of the few remaining ice-tongue fjord environments.

Assessing site-use and sources of disturbance at walrus haul-outs using monitoring cameras

The rapid growth of tourism in Polar Regions stimulates a need for investigating potential impacts on targeted species and sensitive areas. This study examines effects of tourist visitations on haul-out dynamics and site use by walruses (Odobenus rosmarus) in Svalbard, Norway. Automated camera stations were established at five traditional haul-out sites that experience variable levels of tourist visitation. The cameras took one photograph each hour, throughout June–November from 2007 to 2015 (3 sites) and 2010–2015 (2 additional sites). A total of 66,365 images were analysed. The approximate number of walruses on shore, and % sea-ice cover was estimated for each image; additionally, the presence/absence of tourists, boats and polar bears (Ursus maritimus) were recorded. A log-linear regression model was run on residuals from an ARIMA model, fitted to each season of counts from each site. Use of the terrestrial haul-out sites was sometimes restricted by sea-ice cover, but walruses were also absent (or present rarely) at some sites, despite a lack of sea ice. Tourists on land and boats near the haul-out sites (with a single exception) did not disturb walrus haul-out behaviour significantly (p > 0.05) at any of the sites. In addition, most polar bear visits were not associated with detectable disturbances. However, polar bears did significantly disturb walrus herds at Andreetangen (p = 0.003) and Storoya (p = 0.002) in some years. These disturbances were likely associated with predation attempts on calves.

Haul-out behaviour of Arctic ringed seals (Pusa hispida): inter-annual patterns and impacts of current environmental change

Hauling out onto a solid substrate is an integral part of most pinnipeds’ activity budgets. Ringed seals (Pusa hispida) are an Arctic species that hauls out on sea ice routinely throughout the year. In 2006, a sudden change in the sea-ice regime occurred in Svalbard (Norway). Amongst other changes, the amount of land-fast ice declined sharply. This study examined the intra- and inter-annual haul-out behaviour of 60 ringed seals equipped with Satellite Relay Data Loggers before [2002–2003 (n = 22)] and after [2010–2012 (n = 38)] the sea-ice decline occurred. In total, ringed seals hauled out 5–20% of the time (between August and May) with a mean haul-out duration of 3.3 h. The mean interval between haul-out events was 36 h, with a seasonal pattern that peaked in October (max 81 days). Haul-out probability was influenced by wind speed, temperature and solar hour to varying extents seasonally. After the sea-ice decline, intervals between haul-out events were significantly longer, and from December to March seals had shorter haul-out durations and hauled out a smaller proportion of the time. Haul-out probabilities in the winter and spring were more heavily influenced by weather conditions in 2010–2012 compared to 2002–2003, especially on the west coast where sea-ice declines have been greatest. These changes are likely due to ringed seals hauling out less often in snow lairs due to inadequate snow and ice conditions. Ringed seal haul-out behaviour will likely continue to be impacted negatively by ongoing environmental change, with concomitant impacts on their activity/energy budget and polar bears’ hunting behaviour.

Attempted Predation of a Harbor Seal Pup (Phoca vitulina) by an American Mink (Neovison vison) in the Salish Sea

Abstract A single incident of attempted predation of a Harbor Seal (Phoca vitulina) pup by an American Mink (Neovision vision) was observed on Blakely Island, Washington in 2015. San Juan County Marine Mammal Stranding Network members responded, investigated the event, and performed a necropsy on the seal. Predation is the most parsimonious explanation for the attack due to the American Mink's opportunistic predatory tendencies and the vulnerability of the moribund Harbor Seal. With both the American Mink and Harbor Seal populations documented as abundant or at carrying capacity, respectively, mink predation on vulnerable Harbor Seal pups could increase or influence Harbor Seal haul-out behavior.

Bimodal Winter Haul-Out Patterns of Adult Weddell Seals (Leptonychotes weddellii) in the Southern Weddell Sea.

Hauling out is an essential component of pinniped life-history. Haul-out behaviour may be affected by biological (e.g. sex, age and condition) and physical factors (e.g. food availability and environmental conditions), and identifying these factors may help explain the spatio-temporal distribution and habitat use of pinnipeds. The aim of this study is to describe observed winter haul-out patterns of adult Weddell seals in the Weddell Sea and investigate the role of potential predictors to gain insight into the way these animals interact with the physical environment in this region. We examined the haul-out behaviour in relation to available biological (i.e., diving effort, sex) and physical information (i.e., sun angle). Thirty-three satellite telemetry tags were deployed on adult Weddell seals in the southern Weddell Sea during February 2007, 2009 and 2011, following their annual moult recording information on the behavioural mode of the animal: at surface, hauled out or diving. At the end of the austral summer Weddell seals spent, on average, more than 40% of their time hauled out on the ice. Under constant light conditions, it appears that physiological factors drive sex differences in the timing and duration of haul-out behaviour, with females spending on average more time hauled out than males during daylight hours. This time spent hauled-out declined to around 15% in both sexes by the beginning of autumn and remained at this level with a clear nocturnal haul-out pattern during the winter. The time spent diving increased during this period, indicating an increase in foraging effort during the winter months, and led to a common haul-out pattern in both sexes over winter. We found a positive relationship between haul-out duration and the percentage of time spent diving prior to a haul-out in both sexes, with the exception of female daytime haul-outs early in the year.

Seasonal, meteorological, tidal and diurnal effects on haul-out patterns of harbour seals (Phoca vitulina) in Iceland

It is of critical importance to identify factors that affect harbour seal haul-out patterns to improve the accuracy of harbour seal censuses. In this study, haul-out patterns of harbour seals (Phoca vitulina) were investigated during different conditions at several major haul-out sites on Vatnsnes peninsula, NW Iceland (65°40′N and 20°48′W), over the 2008–2011 period. A seasonal haul-out pattern was detected among the seals, with the maximum number of seals on land found in July for most of the sites. Analyses of data for harbour seals on Vatnsnes indicate that the main pupping period occurs during late May to the beginning of June and moulting during late July to early August. Abundance at the sites increased with rising air temperature and decreased with increased windspeed and rising tides. However, no evidence that precipitation or cloud cover affected haul-out behaviour of the seals was detected. The diel haul-out pattern was investigated thoroughly in one of the haul-out sites and the results underlined the effect of tidal flucturation, air temperature and wind direction on the haul-out behaviour of harbour seals in the area. Results from this study can be used to improve the survey design when estimating the population size of harbour seals in Iceland and applied more broadly to the study of haul-out behaviour of harbour seals.

Variability in haul-out behaviour by male Australian sea lions Neophoca cinerea in the Perth metropolitan area, Western Australia

Pinnipeds spend significant time hauled out, and their haul-out behaviour can be dependent on environment and life stage. In Western Australia, male Australian sea lions Neo - phoca cinerea haul out on Perth metropolitan islands, with numbers peaking during aseasonal (~17.4 mo in duration), non-breeding periods. Little is known about daily haul-out patterns and their association with environmental conditions. Such detail is necessary to accurately monitor behavioural patterns and local abundance, ultimately improving long-term conservation manage- ment, particularly where, due to lack of availability, typical pup counts are infeasible. Hourly counts of N. cinerea were conducted from 08:00 to 16:00 h on Seal and Carnac Islands for 166 d over 2 yr, including 2 peak periods. Generalised additive models were used to determine effects of temporal and environmental factors on N. cinerea haul-out numbers. On Seal Island, numbers increased significantly throughout the day during both peak periods, but only did so in the second peak on Carnac. During non-peak periods there were no significant daytime changes. Despite high day-to-day variation, a greater and more stable number of N. cinerea hauled out on the sig- nificantly smaller beach of Seal Island during 1 peak. Overall, numbers hauled out were associ- ated with temperature and tidal height, but not wind speed. Relative percentages of age classes hauled out also varied with time of breeding cycle. Due to high variability in haul-out behaviour in space and time, and its association with environmental conditions, we conclude that counts for monitoring relative abundance in management decisions should be conducted systematically, using robust survey designs with relatively large sample sizes.

Factors Affecting Haul-Out Behavior of Harbor Seals (Phoca vitulina) in Tidewater Glacier Inlets in Alaska: Can Tourism Vessels and Seals Coexist?

Large numbers of harbor seals (Phoca vitulina) use habitat in tidewater glaciers in Alaska for pupping, breeding, and molting. Glacial fjords are also popular tourist destinations; however, visitation by numerous vessels can result in disturbance of seals during critical life-history phases. We explored factors affecting haul-out behavior of harbor seals at a glacial site frequented by tourism vessels. In 2008-10, we deployed VHF transmitters on 107 seals in Endicott Arm, Alaska. We remotely monitored presence and haul-out behavior of tagged seals and documented vessel presence with time-lapse cameras. We evaluated the influence of environmental and physical factors on the probability of being hauled out, duration of haul-out bouts, and as factors associated with the start and end of a haulout. Location, season, hour, and interactions of location by year, season, hour, and sex significantly influenced haul-out probability, as did ice, weather, and vessels. Seals were more likely to be hauled out with greater ice availability during the middle of the day, and less likely to be hauled out if vessels were present. Cruise ships had the strongest negative effect; however, most vessel types negatively affected haul-out probability. Haul-out duration was longest in association with starting on incoming tides, clear skies, no precipitation, occurring in the middle of the day, and ending in the late afternoon or evening. End of haulouts was associated with increasing cloud cover, low ice availability, and vessel presence; large-sized tourism vessels or all-vessel-types combined were significant predictors of ending a haul-out bout. Probability of being hauled out was highest in June, during pupping season. Potential disturbances of harbor seals could be reduced, enabling longer resting times for seals and fewer interruptions for nursing pups, if vessels focused the majority of visits to glacial habitat to before or after the hours of 08:00-17:00 or, less optimally, 09:00-16:00.

Year-round haul-out behaviour of male walruses Odobenus rosmarus in the Northern Barents Sea

Haul-out behaviour is a central component in the life history of pinnipeds; seasonal patterns in this behaviour reveal insights into annual energy budgets and basic biology. In this study, custom-designed satellite-relay data loggers were deployed on 17 male walruses Odobenus rosmarus in Svalbard, Norway. Individual animals transmitted data for a mean ± SD of 255 ± 132 d (range = 54�471 d), performing on average 110 ± 65 haul-out events (range = 30�247 events); the data records for 5 animals were longer than 1 yr. Clear seasonal patterns occurred in the percent- age of time hauled out and average haul-out duration; both variables reached maxima in summer and minima in winter. Time between haul-out events reached a maximum during the breeding season in winter. The walruses moved away from shore-based haul-out sites and onto sea ice in November and December, and returned to land again in June. Analyses using generalized addi- tive mixed models and Cox proportional hazard models demonstrated that wind chill and time in the water prior to a haul-out event had the largest impacts on haul-out probability and duration, although wind chill had little impact during the summer when temperatures were not challenging, and also had reduced influence during the breeding period. Long periods at sea were followed by long periods hauled out, resulting in a relatively constant proportion of time spent hauled out over time scales of weeks. Our results indicate the importance of breeding in dictating male haul-out patterns during winter, and provide a baseline to assess impacts of future climate change.