Fur Seals Research Articles

The distribution, abundance, status and global importance of giant petrels (Macronectes giganteus and M. halli) breeding at South Georgia

Information on the status of giant petrels breeding at South Georgia was previously based on studies at a small number of the archipelago's breeding sites. Here, we report the results of the first complete archipelago-wide survey of breeding northern Macronectes halli and southern M. giganteus giant petrels in the austral summers 2005/2006 and 2006/2007. We estimate that 15,398 pairs of northern and 8803 pairs of southern giant petrels bred at South Georgia. These are the largest and second largest populations at any island group, representing 71.0% and 17.3%, respectively, of updated global estimates of 21,682 pairs of northern and 50,819 pairs of southern giant petrels. A comparison of counts at locations surveyed in both 1986/1987–1987/1988 and 2005/2006–2006/2007 indicated increases of 74% and 27% in northern and southern giant petrels, respectively, over the intervening 18–20 years. The greater increase in northern giant petrels was likely influenced by the recovery of the Antarctic fur seal Arctocephalus gazella population at South Georgia, which provides an abundant but transient food resource (carrion). Due to allochrony, this provides greater benefits to northern giant petrels. The large, and increasing, population of king penguins Aptenodytes patagonicus at South Georgia also provides a potentially valuable food resource. The flexible and opportunistic foraging behaviour of giant petrels has contributed to their positive population trends. Other, more specialised, seabirds such as albatrosses have declined at South Georgia in recent decades mainly because of problems at sea, compounded by greater predation pressure from the increasing populations of giant petrels.

Impacts of extreme ocean warming on the early development of a marine top predator: The Guadalupe fur seal

From fall 2013 through 2015, a large-scale, multi-year warm water anomaly occurred in the northeast Pacific Ocean. The phenomenon had negative impacts on some oceanic predators, including higher mortalities and poor body conditions. We studied the effect of this warm water anomaly on the weight gain of Guadalupe fur seal (Arctocephalus philippii townsendi) neonates off the coast of the Baja California Peninsula, Mexico. Individuals were captured, marked, and weighed every 13–15 days, up to 60 days of age, during the early nursing seasons (mid-June to mid-August) of 2014–2016 at this subspecies’ only reproductive colony, located on Guadalupe Island. The body weight was measured at each capture and recapture. A hierarchical Bayesian model was used to explore the impact of sea surface temperature (SST) anomalies on the neonates’ weights. The hierarchical structure included connected models for the spring-summer SST trend around the colony, the neonatal body weight gain with age, and the relationship between the anomalies of both variables. Marked neonates were also tracked in order to estimate survival rates during first two months of age. Overall, positive SST anomalies had a negative effect on neonatal body weight gain. The northeast Pacific Marine Heatwave precipitated the lowest weights at birth and the slowest weight gain in 2014, as well as low weights and the lowest survival rate in 2015, likely due to the persistence of the warm anomalies. The evident sensitivity of Guadalupe fur seal neonates to regional warming conditions highlights their vulnerability under scenarios of climate change, which could impede this subspecies’ continued recovery from near extinction.

Toxoplasmosis and Sarcocystis spp. infection in wild pinnipeds of the Brazilian coast.

The protozoans Toxoplasma gondii and Sarcocystis spp. (Sarcocystidae: Apicomplexa) affect a wide variety of vertebrates. Both have been reported to infect pinnipeds, with impacts on health ranging from inapparent to fulminant disease and death. However, little is known regarding their infections and associated pathology in South American pinnipeds. We used histological techniques to survey for the presence of T. gondii and Sarcocystis spp. in 51 stranded pinnipeds from Brazil. Immunohistochemical and molecular assays were employed in those cases consistent with Sarcocystidae infection. T. gondii cysts were detected in the central nervous system and heart of a South American fur seal Arctocephalus australis, associated with meningoencephalitis, myocarditis and endocarditis, and confirmed by immunohistochemistry. Additionally, this animal presented Sarcocystis sp. cysts in brain and heart tissues. Four additional specimens-2 Subantarctic fur seals A. tropicalis, an Antarctic fur seal A. gazella and another South American fur seal-presented intrasarcoplasmic cysts compatible with Sarcocystis spp. in muscle samples. There was no inflammation associated with the Sarcocystis spp. tissue cysts and all cysts were negative for S. neurona immunohistochemistry. The B1 gene of T. gondii was amplified in the 5 pinnipeds infected by Sarcocystidae protozoans. To our knowledge, this is the first report of toxoplasmosis in wild South American pinnipeds and of Sarcocystis spp. in South American fur seals. Detection of terrestrial parasites in aquatic mammals could be an indicator of their presence in the marine environment.

Seals, Empires and Mass Politics: The 1893 Fur Seal Arbitration

The 1893 Paris Arbitration sought to resolve an ecological crisis in the North Pacific Fur Seal population that had become an economic and political crisis. Overlapping webs of capital, identity and commodities created a series of seasonal ‘war scares’ between the United States and the British Empire. Mass Politics in Canada and the United States served to propel the crisis, and to prevent its resolution by normal diplomatic means. Seeking an escape from the conundrum, the powers submitted the question to Arbitration. This episode sheds light, therefore, on the mechanisms by which the diplomatic services of global empires reacted to the late-nineteenth century pressures of mass consumption, mass politics, and mass ecological destruction.

Prevalence of serum antibodies to Coxiella burnetii in Alaska Native Persons from the Pribilof Islands.

Q fever is a febrile illness caused by infection with the bacterium Coxiella burnetii. It is most often transmitted by inhalation of the bacteria after it is shed by infected livestock. Recent studies have found very high C. burnetii infection rates among marine mammals, but it is not known if shedding by marine mammals creates a risk of Q fever among humans. To better understand infection of humans with exposure to marine mammals, the prevalence of antibodies against C. burnetii in serum samples taken from Alaskan Native persons residing on the Pribilof Islands was evaluated. The Pribilof Islands support large populations of northern fur seals infected with C. burnetii that may increase the risk of exposure for island residents. Serum testing for IgG antibodies against C. burnetii (phase I and phase II) was performed, and demographic data were analysed utilizing banked serum specimens drawn from island residents from 1980 to 2000. The overall seroprevalence rate was 11.6% (95% CI=9.3%-14.4%; 72/621). This is higher than the previously reported 3.1% (95% CI=2.1%-4.3%) seroprevalence for the U.S. These results suggest that Alaskan Native persons may be at higher risk for exposure to C. burnetii than the general US. population, possibly due to proximity to large populations of infected marine mammals.

Lifetime coastal and oceanic foraging patterns of male Guadalupe fur seals and California sea lions

AbstractCarcasses of adult and subadult male Guadalupe fur seals (GFSs) are beached on Isla Magdalena, representing about 73% of all GFSs beachings since 2003. Analysis of carbon and nitrogen stable isotopes in dentin collagen from male GFSs was used in an attempt to distinguish animals from two possible locations of origin: the oceanic Guadalupe Island (GI) and the coastal San Benito Islands (SBI). Samples of conterminous and contemporary California sea lions (CSLs) were included as representative of coastal predators. Two distinct groups of GFSs were evident based on δ13C values: coastal GFSs with higher δ13C values than CSLs, and oceanic GFSs with lower δ13C values than CSLs. Significant temporal trends were observed in the δ15N values; values for oceanic GFSs and CSLs increased annually (0.082‰ and 0.089‰, respectively), while those for coastal GFS decreased annually by 0.183‰. The isotopic segregation of oceanic and coastal GFS males, presumably from GI and SBI respectively, has been present at least since the mid‐1990s. This segregation may be due to dissimilar ingestion of prey from oceanic vs. coastal origin prior to their seasonal co‐occurrence in the Gulf of Ulloa.

Increased alertness behavior in Australian fur seals (Arctocephalus pusillus doriferus) at a high vessel traffic haul‐out site

AbstractVessel impacts on marine mammals are of growing concern, and marine mammals in urbanized marine environments are at particular risk of exposure. Port Phillip Bay (Victoria, Australia) is one such environment, in which Australian fur seals (AUFS; Arctocephalus pusillus doriferus) haul‐out to rest, yet little is known about the impacts of vessels on resting seals. We used remote camera traps to investigate the influence of vessel traffic on AUFS behavior at a nonbreeding haul‐out site. Environmental, temporal, and vessel‐related variables were all associated with changes in AUFS alertness at this site. All vessel types elicited increased alertness above base‐line levels (25%), with recreational and commercial motorized vessels associated with a 5.7%–10.8% increase in alertness. Unidentified vessels, the government vessel, and kayaks were associated with significantly increased alertness of 21.7%, 46.4%, and 60.7%, respectively, though accounted for only 6.2% of vessel observations. Vessels breaching current approach regulations (<5 m) showed a 32% increase in alertness, significantly higher than nonbreach approaches. Partial and complete flushing of the platform was rare, occurring in 1.0% of images analyzed. These results suggest that vessels do elicit a response from AUFS at this haul‐out site, and that further monitoring of vessel activity and compliance is required.

What do we know about the fossil record of pinnipeds? A historiographical investigation.

The fossil record of pinnipeds (seals, fur seals and walruses) is globally distributed, spanning from the late Oligocene to the Holocene. This record shows a complex evolutionary history that could not otherwise be inferred from their extant relatives, including multiple radiations and iterative ecomorphological specializations among different lineages, many of which are extinct. The fossil record of pinnipeds is not uniformly represented in space and time, however, leaving some gaps in our knowledge. We performed a historiographical investigation of the published fossil record of pinnipeds based on the information available in the Paleobiology Database, with the aim to broadly characterize and evaluate it from a taxonomic, geographical and temporal perspective. We identified major trends, strengths and weaknesses of the pinniped fossil record, including potential biases that may affect our interpretations. We found that 39% of the record corresponds to extant taxa, which are essentially from the Pleistocene and Holocene. There is a larger record from the Northern Hemisphere, suggesting biases in sampling and collection effort. The record is not strongly biased by sedimentary outcrop bias. Specifically, for extinct species, nearly half of them are represented by a single occurrence and a large proportion have type specimens consisting of single isolated postcranial elements. While the pinniped fossil record may have adequate temporal and taxonomic coverage, it has a strong geographical bias and its comparability is hindered by the incompleteness of type specimens. These results should be taken into account when addressing patterns of their past diversity, evolutionary history and paleoecology.

Re‐evaluating the population size of South American fur seals and conservation implications

Abstract South American fur seals (Arctocephalus australis) are widely distributed, yet surprisingly little is known about their ecology. In particular, population data are sparse and outdated for many breeding locations, including the Falkland Islands. Data deficiency impedes the development of coherent conservation and management strategies. To address knowledge gaps, for the first time since 1965 an archipelago‐wide census of South American fur seals breeding at the Falkland Islands was undertaken, which provided the first pup abundance estimate since 1926 – data that are critical for assessing population trends. In total, 36,425 South American fur seal pups were counted at the Falkland Islands in 2018, a greater than four‐fold increase since the last census, and far greater than the 7,990 pups counted in Uruguay, which was presumed to be the largest South American fur seal population in the world. Hence, based on pup abundance, the Falkland Islands is presently the largest population of South American fur seals, even when considering a correction factor of 3.9 that was applied to pup counts in Uruguay, which yielded an estimated 31,160 pups. The results redefine South American fur seal abundance, the contribution of breeding locations (Falkland Islands, Uruguay, Argentina, Chile) and the distribution of breeding colonies at the Falkland Islands, which has far reaching implications for conservation and management. In particular, the present study has effectively doubled the Atlantic population size of the species, which is now estimated to comprise about 76,000 pups, of which the Falkland Islands accounts for 48% and Uruguay 41%. Accordingly, changes in the number of South American fur seals breeding at the Falkland Islands will influence the global population trends and conservation status of the species. Monitoring South American fur seals breeding at the Falkland Islands is therefore crucial to understand the impacts of anthropogenic pressures, such as fisheries, and to inform management and conservation policy. The results provide a baseline from which to measure changes in abundance.

Study on Present Scenario of Bangladesh Ship Building Industries, Underlying Problems and Probable Solution

We are living in a competitive world. To develop economic condition of any country, industrial sector plays a major role. There are so many industries in our country in our country. Among these sector ship building is an important activity in context of Bangladesh. Ship building industries have been located along the coastal belt and riverbanks of Bangladesh. Ship building industry generates large amount of revenues for the country. The sea borne cargo growth is increasing 6-8% per year and demand of new ship building is increasing at the rate of 3-4% per year. Considering the world market and internal market, it is assumed that Bangladesh has a bright future to elevate herself as a ship building nations in the world market and surely that factor should encourage more Bangladeshi entrepreneurs to come forward in this business. Experts say more than 55% of the world`s ship are more than 20 years old and need replacing. Globally, this small and medium sized ship market is worth around $400 billion. If Bangladesh can get 1% of this market, then it amounts to $4 billion. Our research deals with the last few condition of ship building industry in Bangladesh. We also discuss about the condition of worker and environmental pollution & underlying problems of shipbuilding in Bangladesh. Finally, we formulating some suggestion which can be taken by the government and the private sector to improve the condition of ship building industry and creating demand for our ships in the world market.

A Study on Present Scenario of Bangladesh Ship Building Industries, Underlying Problems and Probable Solution

We are living in a competitive world. To develop economic condition of any country, industrial sector plays a major role. There are so many industries in our country in our country. Among these sector ship building is an important activity in context of Bangladesh. Ship building industries have been located along the coastal belt and riverbanks of Bangladesh. Ship building industry generates large amount of revenues for the country. The sea borne cargo growth is increasing 6-8% per year and demand of new ship building is increasing at the rate of 3-4% per year. Considering the world market and internal market, it is assumed that Bangladesh has a bright future to elevate herself as a ship building nations in the world market and surely that factor should encourage more Bangladeshi entrepreneurs to come forward in this business. Experts say more than 55% of the world`s ship are more than 20 years old and need replacing. Globally, this small and medium sized ship market is worth around $400 billion. If Bangladesh can get 1% of this market, then it amounts to $4 billion. Our research deals with the last few condition of ship building industry in Bangladesh. We also discuss about the condition of worker and environmental pollution & underlying problems of shipbuilding in Bangladesh. Finally, we formulating some suggestion which can be taken by the government and the private sector to improve the condition of ship building industry and creating demand for our ships in the world market.

Links between muscle phenotype and life history: differentiation of myosin heavy chain composition and muscle biochemistry in precocial and altricial pinniped pups.

In marine mammals, muscular development has been identified as a rate-limiting factor in achieving adult dive capacities. This study investigates the rate that myosin heavy chain (MHC) composition matures in a postural and locomotor skeletal muscle for four pinniped species with different lactation lengths: hooded seals, Cystophora cristata; harp seals, Pagophilus groenlandicus; northern fur seals, Callorhinus ursinus, and Steller sea lions, Eumetopias jubatus. The ontogeny of MHC isoform expression was compared with developmental rates of myoglobin concentrations, and aerobic (citrate synthase, β-hydroxyacyl-CoA dehydrogenase) and anaerobic (lactate dehydrogenase) enzyme activities. Within taxonomic families, species with shorter lactation periods had more mature muscles biochemically at birth, and fiber types differentiated earlier during ontogeny (Phocidae: hooded > harp seals, Otariidae: northern fur seals > Steller sea lions). Northern fur seal neonates had the most phenotypically-mature muscles in this study, with no immature MHC isoforms. The relationship between muscle biochemistry and MHC composition became more pronounced with age, and developed to reflect swimming mode and activity levels. In adults, phocids had more slow-twitch oxidative protein in their primary locomotor muscle, the Longissimus dorsi (LD), than otariids which likely reflects oxygen-sparing strategies for the phocids' longer dives. Conversely, northern fur seal muscles had higher proportions of fast-twitch MHCs in the Pectoralis and LD, likely indicative of this species' smaller size and higher mass-specific metabolic rates. Thus, muscle phenotype is linked with species life history, and a mismatch between muscle biochemistry and MHC composition at weaning has important implications for the first year of independent foraging in pinniped pups.

Squid in the diet of Antarctic fur seals: potential links to oceanographic conditions and Antarctic krill abundance

Squid in the diet of Antarctic fur seals: potential links to oceanographic conditions and Antarctic krill abundance

Prey differences drive local genetic adaptation in Antarctic fur seals

Prey differences drive local genetic adaptation in Antarctic fur seals

Identifying foraging habitats of adult female long-nosed fur seal Arctocephalus forsteri based on vibrissa stable isotopes

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 628:223-234 (2019) - DOI: https://doi.org/10.3354/meps13113 Identifying foraging habitats of adult female long-nosed fur seal Arctocephalus forsteri based on vibrissa stable isotopes Dahlia Foo1,*, Mark Hindell1, Clive McMahon2, Simon Goldsworthy3 1Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania 7004, Australia 2Sydney Institute of Marine Science, Mosman, New South Wales 2088, Australia 3Aquatic Sciences Centre, South Australian Research and Development Institute, West Beach, South Australia 5024, Australia *Corresponding author: dahlia.foo@utas.edu.au ABSTRACT: We investigated how foraging ecotypes of female long-nosed fur seals Arctocephalus forsteri could be identified from vibrissa stable isotopes. We collected regrowths of vibrissae from adult females (n = 18) from Cape Gantheaume, Kangaroo Island, South Australia, from 2 breeding seasons (2016, 2017). The period represented by the regrowth was known, and 8 individuals were administered with 15N-enriched glycine as a biomarker to mark the start date of the regrowth. Non-glycine-marked and glycine-marked vibrissae were used to estimate the rate of the individual vibrissa regrowth. Using individual growth rates (0.18 ± 0.04 mm d-1), we reconstructed a stable isotope (δ13C and δ15N) time series for each regrowth and allocated them to corresponding at-sea locations either based on geolocation tracks (n = 14) or foraging habitat type (shelf or oceanic) based on diving data (n = 2) of the sampled seals. Mean (±SD) δ15N from vibrissa segments was higher when females foraged on the continental shelf region (16.1 ± 0.7‰, n = 29) compared to oceanic waters (15.1 ± 0.7‰, n = 106) in 2017, whereas it was similar in both regions in 2016 (shelf: 15.3 ± 0.4‰, n = 13; oceanic: 15.4 ± 0.4‰, n = 15). Based on the stable isotope signatures of vibrissa segments, model-based clustering analysis correctly classified 79.8% as originating from shelf or oceanic foraging habitats. This demonstrates the potential of using vibrissa stable isotopes for studying the foraging ecology of an important top marine predator. KEY WORDS: Isoscape · Foraging strategies · Trophic dynamics · Continental shelf · Oceanic · Marine top predators Full text in pdf format Supplementary material PreviousCite this article as: Foo D, Hindell M, McMahon C, Goldsworthy S (2019) Identifying foraging habitats of adult female long-nosed fur seal Arctocephalus forsteri based on vibrissa stable isotopes. Mar Ecol Prog Ser 628:223-234. https://doi.org/10.3354/meps13113 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 628. Online publication date: October 10, 2019 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2019 Inter-Research.

Dive behaviour and foraging effort of female Cape fur seals Arctocephalus pusillus pusillus.

While marine top predators can play a critical role in ecosystem structure and dynamics through their effects on prey populations, how the predators function in this role is often not well understood. In the Benguela region of southern Africa, the Cape fur seal (Arctocephalus pusillus pusillus) population constitutes the largest marine top predator biomass, but little is known of its foraging ecology other than its diet and some preliminary dive records. Dive information was obtained from 32 adult females instrumented with dive recorders at the Kleinsee colony (29°34.17′ S, 16°59.80′ E) in South Africa during 2006–2008. Most dives were in the depth range of epipelagic prey species (less than 50 m deep) and at night, reflecting the reliance of Cape fur seals on small, vertically migrating, schooling prey. However, most females also performed benthic dives, and benthic diving was prevalent in some individuals. Benthic diving was significantly associated with the frequency with which females exceeded their aerobic dive limit. The greater putative costs of benthic diving highlight the potential detrimental effects to Cape fur seals of well-documented changes in the availability of epipelagic prey species in the Benguela.

New non-breeding colonies of the South American fur seal in central Chile. Is the distribution in the southeastern Pacific waters extending?

The South American fur seal (SAFS), Arctocephalus australis, has an estimated abundance of 219,000 individuals. The distribution range of this top marine predator along the Pacifc coast of South America is discontinuous, with a gap between 29°02’S-43°36’S, whereas the Atlantic coast presents a continuous distribution. Little is known aboutthe population dynamics of the species in Chile, as there have been few observations of vagrant individuals within the distribution gap and partial population censuses on dates that do not fit with the reproductive season in northern andsouthern Chile. The aim of this study is to identify the presence of A. australis colonies and summarize the sightings in central Chile. Aerial censuses were performed between 32°12’S-39°24’S during the austral winter and summer (2015) and between 41°44’S-44°55’S during summer (2013, 2016-2018). Official stranding records were also included to complementthe research sightings. We registered a total of 54 SAFS in the Chilean distribution gap, most of them during winter (89%) and with a higher proportion of females (72%). Two non-breeding colonies were found in the Biobío Region during the winter of 2015, Islote del Trabajo (38°25’S) and Islote Quechol (38°26’S), with 27 ± 1 and 16 ± 0 individuals, respectively. The sightings of adult individuals suggest their arrival at these latitudes to carry out foraging and resting activities, probably from Guafo Island (43°36’S). The last Pleistocene glaciation, hunting activities during the eighteenth century and ENSO events could have conditioned the current abundance and range of distribution of A. australis in South America; therefore, the establishment of new non-breeding colonies in the gap of distribution could lead to new breeding grounds in thefuture.

Migratory strategies of juvenile northern fur seals (Callorhinus ursinus): bridging the gap between pups and adults

In species exhibiting differential migration by sex and age, understanding what differences exist, and the adaptive reasons for these differences is critical for determining how demographic groups will respond to environmental variability and anthropogenic perturbations. We used satellite-telemetered movement and diving data to investigate differential migration and its ontogeny in a highly migratory North Pacific Ocean predator, the northern fur seal (Callorhinus ursinus; NFS), with a focus on understudied juvenile (1- to 2-year-old) animals. We instrumented 71 juvenile NFS in two years (2006–07 and 2007–08) at three major North American breeding sites and compared their migratory strategies with pups and adults. Although sexual dimorphism is strong in adult NFS, only weak differences in body mass between sexes were found in juveniles, which had similar body mass to pups (~3–4 months). However, unlike widely-dispersed pups, juvenile male and female NFS dispersed in different directions, and used different habitats characterized by distinct hydrography and prey assemblages during migration, similar to breeding adults. Juvenile diving behavior differed only modestly among habitats and between sexes, consistent with weak differences in body mass. Evidence of habitat sexual segregation by juvenile NFS contradicts previous hypotheses that physiological differences predominantly drive the ontogeny of differential migration.

A method to estimate pre‐exploitation population size

Antarctic fur seals (Arctocephalus gazella) were commercially exploited on the subantarctic island of South Georgia for over 100 years and nearly driven to extinction. Since the cessation of harvesting, however, their populations have rebounded, and they are now often considered a nuisance species whose impact on the terrestrial landscape should be mitigated. Any evaluation of their current population requires the context provided by their historic, pre-exploitation abundance, lest ecologists fall prey to shifting baseline syndrome in which their perspective on current abundance is compared only with an altered state resulting from past anthropogenic disturbance. Estimating pre-exploitation abundance is critical to defining species recovery and setting recovery targets, both of which are needed for the International Union for the Conservation of Nature's recent efforts to develop a green list of recovering species. To address this issue, we reconstructed the South Georgia fur seal harvest from 1786 to 1908 from ship logbooks and other historical records and interpolated missing harvest data as necessary with a generalized linear model fit to the historical record. Using an approximate Bayesian computation framework, harvest data, and a stochastic age-structured population model, we estimated the pre-exploitation abundance of Antarctic fur seals on South Georgia was 2.5 million females (95% CI 1.5-3.5 million). This estimate is similar to recent abundance estimates, and suggests current populations, and the ecological consequences of so many fur seals on the island, may be similar to conditions prior to human harvest. Although the historic archive on the fur sealing era is unavoidably patchy, the use of archival records is essential for reconstructing the past and, correspondingly, to understanding the present. Article impact statement: Defining species recovery requires an understanding of baseline population state, which can be estimated through statistical methods.

Preferred, small-scale foraging areas of two Southern Ocean fur seal species are not determined by habitat characteristics

BackgroundTo understand and predict the distribution of foragers, it is crucial to identify the factors that affect individual movement decisions at different scales. Individuals are expected to adjust their foraging movements to the hierarchical spatial distribution of resources. At a small local scale, spatial segregation in foraging habitat happens among individuals of closely situated colonies. If foraging segregation is due to differences in distribution of resources, we would expect segregated foraging areas to have divergent habitat characteristics.ResultsWe investigated how environmental characteristics of preferred foraging areas differ between two closely situated Subantarctic fur seal (Arctocephalus tropicalis) colonies and a single Antarctic fur seal (A. gazella) colony that forage in different pelagic areas even though they are located well within each other’s foraging range. We further investigated the influence of the seasonal cycle on those environmental factors. This study used tracking data from 121 adult female Subantarctic and Antarctic fur seals, collected during summer and winter (2009–2015), from three different colonies. Boosted Regression Tree species distribution models were used to determine key environmental variables associated with areas of fur seal restricted search behaviour. There were no differences in the relative influence of key environmental variables between colonies and seasons. The variables with the most influence for each colony and season were latitude, longitude and magnitude of sea-currents. The influence of latitude and longitude is a by-product of the species’ distinct foraging areas, despite the close proximity (< 25 km) of the colonies. The predicted potential foraging areas for each colony changed from summer to winter, reflecting the seasonal cycle of the Southern Ocean. The model predicted that the potential foraging areas of females from the three colonies should overlap, and the fact they do not in reality indicates that factors other than environmental are influencing the location of each colony’s foraging area.ConclusionsThe results indicated that small scale spatial segregation of foraging habitats is not driven by bottom-up processes. It is therefore important to also consider other potential drivers, e.g. competition, information transfer, and memory, to understand animal foraging decisions and movements.