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Journal articles on the topic 'South African fur seal'

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Published: 4 June 2021

Last updated: 28 January 2023

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1

Almansa Ruiz, José Carlos, Carol Knox, Sonja Boy, and Gerhard Steenkamp. "Dentigerous cyst in a South African fur seal (Arctocephalus pusillus pusillus)." Veterinary Record Case Reports 8, no. 2 (June 2020): e001180. http://dx.doi.org/10.1136/vetreccr-2020-001180.

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The dental pathology of pinnipeds has been well studied with periodontal disease the most common dental pathology accounting for 19.4–91.8 per cent of all dental pathologies. An eight-month-old stranded South African fur seal (Arctocephalus pusillus pusillus) was rescued from the south coast of South Africa; during his rehabilitation process his handlers noticed the absence of his left maxillary canine tooth (204). Eleven years later, during a health examination, the veterinarian upon closed examination could visualise approximately 5 mm of a tooth crown in the area where tooth 204 should have been. A presumed diagnosis of a dentigerous cyst was made based on the radiological findings. Surgery was performed to surgically extract 204 and enucleate the cyst lining. The histological analysis of the enucleated cyst lining confirmed the first reported case of a dentigerous cyst in a marine mammal.

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2

Brunner, S., P. D. Shaughnessy, and M. M. Bryden. "Geographic variation in skull characters of fur seals and sea lions (family Otariidae)." Australian Journal of Zoology 50, no. 4 (2002): 415. http://dx.doi.org/10.1071/zo01056.

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Geographic variation was observed in skulls of several otariid species, with a general change in size corresponding with a change in latitude and primary productivity. The largest specimens were from cool temperate localities, conforming mostly to Rensch's rule. Skulls of Australian sea lions from Western Australia were generally smaller in condylobasal length, but were more robust than those from South Australia. The subantarctic fur seal did not conform to Bergmann's rule: skulls from Amsterdam Island (37�55´S) were largest, those from Gough Island (40�20´S) intermediate and those from Marion Island (46�55´S) the smallest. For both sexes, skulls of southern sea lions from the Falkland Islands were smaller than their equivalents from mainland South America. Similarly, skulls of South African fur seals from south-east South Africa appeared smaller than those from the west coast of South Africa and Namibia; skulls from Namibia grouped separately from those of south-east and west coast, South Africa. We postulate that the Otariidae are in the process of species divergence, much of which may be driven by local factors, particularly latitude and resources.

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3

Scholtyssek, C., and G. Dehnhardt. "Brightness discrimination in the South African fur seal (Arctocephalus pusillus)." Vision Research 84 (May 2013): 26–32. http://dx.doi.org/10.1016/j.visres.2013.03.003.

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4

Pervin, M., T. Izawa, S. Ito, M. Kuwamura, and J. Yamate. "Metastatic Liposarcoma in a South African Fur Seal (Arctocephalus pusillus)." Journal of Comparative Pathology 155, no. 1 (July 2016): 72–75. http://dx.doi.org/10.1016/j.jcpa.2016.05.008.

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5

martin, r. aidan, neil hammerschlag, ralph s. collier, and chris fallows. "predatory behaviour of white sharks (carcharodon carcharias) at seal island, south africa." Journal of the Marine Biological Association of the United Kingdom 85, no. 5 (October 2005): 1121–35. http://dx.doi.org/10.1017/s002531540501218x.

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between 1997 and 2003, there were 2088 natural predations by white sharks (carcharodon carcharias) on cape fur seals (arctocephalus pusillus pusillus) and 121 strikes on towed seal-shaped decoys were documented from observation vessels at seal island, south africa. white sharks at seal island appear to selectively target lone, incoming young of the year cape fur seals at or near the surface. most attacks lasted <1 min and consisted of a single breach, with predatory success rate decreasing rapidly with increasing duration and number of subsequent breaches. a white shark predatory ethogram, composed of four phases and 20 behavioural units, is presented, including four varieties of initial strike and 11 subsequent behaviour units not previously defined in the literature. behaviour units scored from 210 predatory attacks revealed that, for both successful and unsuccessful attacks, polaris breach was the most commonly employed initial strike, while surface lunge was the most frequent second event, closely followed by lateral snap. examination of video footage, still images, and tooth impressions in decoys indicated that white sharks at seal island bite prey obliquely using their anterolateral teeth via a sudden lateral snap of the jaws and not perpendicularly with their anterior teeth, as previously supposed. analysis of white shark upper tooth morphology and spacing suggest the reversed intermediate teeth of white sharks occur at the strongest part of the jaw and produce the largest wound. white shark predatory success at seal island is greatest (55%) within one hour of sunrise and decreases rapidly with increasing ambient light; the sharks cease active predation on seals when success rate drops to ±40%; this is the first evidence of cessation of foraging at unproductive times by any predatory fish. at seal island, white shark predatory success is significantly lower at locations where frequency of predation is highest, suggesting that white sharks may launch suboptimal strikes in areas of greatest intraspecific competition; this is the first evidence of social influence on predation in any elasmobranch. idiosyncratic predatory behaviours and elevated success rates of known individual white sharks at seal island suggest some degree of trial-and-error learning. a hypothetical decision tree is proposed that models predatory behaviour of white sharks attacking cape fur seals at the surface.

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6

Balmelli, M., and P. A. Wickens. "Estimates of daily ration for the South African (Cape) fur seal." South African Journal of Marine Science 14, no. 1 (June 1994): 151–57. http://dx.doi.org/10.2989/025776194784287111.

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7

Wickens, P. A., P. A. Shelton, J. H. M. David, J. G. Field, W. H. Oosthuizen, J.-P. Roux, and A. M. Starfield. "A Fur Seal Simulation Model to Explore Alternative Management Strategies." Canadian Journal of Fisheries and Aquatic Sciences 49, no. 7 (July 1, 1992): 1396–405. http://dx.doi.org/10.1139/f92-155.

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A simulation model is formulated for the South African fur seal (Arctocephalus pusillus pusillus) to evaluate the appropriate management action when culling to reduce population growth rate, culling to decrease fish consumption by seals, or harvesting to maximise numbers of seals removed. There is disturbance associated with bull sealing which increases pup mortality and reduces pregnancy rates, but this is not well quantified. Disturbance can be included or excluded from model runs. To reduce population growth, cow removal is most effective, but the population sex ratio becomes severely altered and this may be undesirable ecologically. Reduction of fish consumption is best achieved either by removing cows, with the same caveat regarding sex ratio, or by removing bulls and including disturbance effects. However, the acceptability of a reduction achieved by humans disrupting seals is questionable, and the continued removal of bulls may eventually lead to further decreases in pregnancy rate. To maximise a harvest, the relative commercial value of different seal products is considered, and bull removal, excluding disturbance effects, followed by removal of pups achieves this aim most effectively.

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8

Strydom, Zanri, Lauren J. Waller, Mark Brown, Hervé Fritz, Kevin Shaw, and Jan A. Venter. "Factors that influence Cape fur seal predation on Cape gannets at Lambert’s Bay, South Africa." PeerJ 10 (June 13, 2022): e13416. http://dx.doi.org/10.7717/peerj.13416.

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Seabird populations experience predation that can impact their breeding density and breeding success. The Cape gannet Morus capensis is endemic to the Benguela upwelling ecosystem and is classified as Endangered by the IUCN. They are affected by several threats, including predation by the Cape fur seal Arctocephalus pusillus pusillus. Many fledglings succumb to predation during their maiden flight across waters around the island. To curb predation, the selective culling of individual predatory seals was implemented in 2014, 2015, and 2018. Our first study objective was to determine if selective culling of Cape fur seals significantly reduced predation probability on Cape gannets. We tested whether predation probability in 2014, 2015, and 2018 was affected by fish biomass, gannet fledgling numbers, and/or the presence/absence of selective culling. Our second objective was to determine what led to fluctuations in Cape fur seal predation on Cape gannet fledglings between 2007 and 2018. We tested whether fish biomass and the amount of Cape gannet fledglings in the water affected predation probability on the fledglings. Results indicated that selective culling reduced predation within years. We found that with both increased fledgling numbers and increased fish biomass, seal predation probability was reduced. This suggests that a sustainable way to promote the conservation of Cape gannets would be to increase food availability for both the Cape fur seals and Cape gannets. Our findings, collectively with the global trend of the declining Cape gannet population and their endemism, provide reasons advocating for the conservation of the food resources of both the Cape fur seal and the Cape gannet in the Benguela system.

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9

Brunner, S. "Cranial morphometrics of the southern fur seals Arctocephalus forsteri and A. pusillus (Carnivora : Otariidae)." Australian Journal of Zoology 46, no. 1 (1998): 67. http://dx.doi.org/10.1071/zo97020.

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The identification and classification of unknown specimens of Arctocephalus from regions of Australasia has proven difficult. Skulls from the New Zealand fur seal (Arctocephalus forsteri) and the Australian fur seal (A. pusillus doriferus), and data from specimens of the South African fur seal (A. p. pusillus), were examined. A visual method was devised to identify and separate A. p. doriferus from A. forsteri for both sexes and for most physiological age-groups. A statistical method for morphometric separation of these species was applied to adult specimens. Characteristics of males and females for both species fell into two broad categories: sexually dimorphic – mainly those characters that increase the ability of males to hold and defend territories; and non-dimorphic – those of functional importance. Studies of geographical variation showed that adult male A. forsteri from Australia were generally larger than those from Macquarie Island and New Zealand. Characteristics of A. p. doriferus were generally larger than those of A. p. pusillus. Nine specimens of New Zealand fur seals were morphologically different from the typical A. forsteri, which indicates the presence of extreme outliers or hybrids in the sample.

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10

Thibault, Marc. "Sighting of a South African fur seal on a beach in south‐western Gabon." African Journal of Ecology 37, no. 1 (March 1999): 119–20. http://dx.doi.org/10.1046/j.1365-2028.1999.00170.x.

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11

Colitz, Carmen M. H., Jens-Christian Rudnick, and Steffen Heegaard. "Bilateral ocular anomalies in a South African fur seal (Arctocephalus pusillus pusillus)." Veterinary Ophthalmology 17, no. 4 (October 8, 2013): 294–99. http://dx.doi.org/10.1111/vop.12100.

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12

Stewardson, Carolyn L., Tania Prvan, and Raymond J. Ritchie. "Climate of a South African fur seal (Arctocephalus pusillus pusillus) breeding island off the south-east coast of South Africa." South African Geographical Journal 94, no. 1 (March 19, 2012): 22–45. http://dx.doi.org/10.1080/03736245.2012.667626.

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13

Lipinski, M. R., and J. H. M. David. "Cephalopods in the diet of the South African fur seal (Arctocephalus pusillus pusillus)." Journal of Zoology 221, no. 3 (July 1990): 359–74. http://dx.doi.org/10.1111/j.1469-7998.1990.tb04007.x.

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14

Penry, Gwenith S., Ashwynn C. Baartman, and Marthán N. Bester. "Vagrant elephant seal predation on Cape fur seal pups, Plettenberg Bay, South Africa." Polar Biology 36, no. 9 (June 8, 2013): 1381–83. http://dx.doi.org/10.1007/s00300-013-1350-4.

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15

Wickens, P. "Conflict between Cape (South African) fur seals and line fishing operations." Wildlife Research 23, no. 1 (1996): 109. http://dx.doi.org/10.1071/wr9960109.

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Cape (South African) fur seals (Arctocephalus pusillus pusillus) interact with line-fishermen in South Africa, particularly during fishing for the migratory species snoek (Thyrsites atun), and mostly when snoek are specifically being targeted. Loss of fish and tackle as a result of seals is estimated to be between at least a half and one million Rand (A$l75000-372000) annually or 3.3-7% of the total annual landed value of snoek. The presence of seals may also disturb fishing operations by causing fish to sound although this is difficult to quantify. Deliberate killing of seals by fishermen during line-fishing occurs indiscriminately and particularly during the peak snoek fishing period; however, estimation of this mortality is currently impossible.

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16

Klein, Richard G., Kathryn Cruz-Uribe, David Halkett, Tim Hart, and John E. Parkington. "Paleoenvironmental and Human Behavioral Implications of the Boegoeberg 1 Late Pleistocene Hyena Den, Northern Cape Province, South Africa." Quaternary Research 52, no. 3 (November 1999): 393–403. http://dx.doi.org/10.1006/qres.1999.2068.

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Boegoeberg 1 (BOG1) is located on the Atlantic coast of South Africa, 850 km north of Cape Town. The site is a shallow rock shelter in the side of a sand-choked gully that was emptied by diamond miners. Abundant coprolites, chewed bones, and partially digested bones implicate hyenas as the bone accumulators. The location of the site, quantity of bones, and composition of the fauna imply it was a brown hyena nursery den. The abundance of Cape fur seal bones shows that the hyenas had ready access to the coast. Radiocarbon dates place the site before 37,000 14C yr ago, while the large average size of the black-backed jackals and the presence of extralimital ungulates imply cool, moist conditions, probably during the early part of the last glaciation (isotope stage 4 or stage 3 before 37,000 14C yr ago) or perhaps during one of the cooler phases (isotope substages 5d or 5b) within the last interglaciation. Comparisons of the BOG1 seal bones to those from regional Middle Stone Age (MSA) and Later Stone Age (LSA) archeological sites suggest (1) that hyena and human seal accumulations can be distinguished by a tendency for vertebrae to be much more common in a hyena accumulation and (2) that hyena and LSA accumulations can be distinguished by a tendency for hyena-accumulated seals to represent a much wider range of individual seal ages. Differences in the way hyenas and people dismember, transport, and consume seal carcasses probably explain the contrast in skeletal part representation, while differences in season of occupation explain the contrast in seal age representation. Like modern brown hyenas, the BOG1 hyenas probably occupied the coast year-round, while the LSA people focused their coastal visits on the August–October interval when nine-to-eleven-month-old seals were abundant. The MSA sample from Klasies River Mouth Cave 1 resembles BOG1 in seal age composition, suggesting that unlike LSA people, MSA people obtained seals more or less throughout the year.

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17

Wickens, P. A., J. H. M. David, P. A. Shelton, and J. G. Field. "Trends in harvests and pup numbers of the South African fur seal: implications for management." South African Journal of Marine Science 11, no. 1 (December 1991): 307–26. http://dx.doi.org/10.2989/025776191784287745.

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18

Botha, JA, SP Kirkman, JPY Arnould, AT Lombard, GJG Hofmeyr, MA Meÿer, PGH Kotze, and PA Pistorius. "Geographic variation in at-sea movements, habitat use and diving behaviour of female Cape fur seals." Marine Ecology Progress Series 649 (September 10, 2020): 201–18. http://dx.doi.org/10.3354/meps13446.

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Knowledge of animal foraging behaviour has implications for management and conservation. While Cape fur seals Arctocephalus pusillus pusillus comprise a major proportion of the southern African marine predator biomass, little is known about their at-sea movements. We investigated foraging distribution, habitat use and diving behaviour for 35 adult female Cape fur seals from 3 breeding colonies experiencing contrasting oceanographic regimes. Animals from Black Rocks, the smallest and eastern-most colony, undertook shorter foraging trips and utilised shallower waters over the shelf. In comparison, animals from the larger west coast colonies, at Kleinsee and False Bay, travelled further and utilised deeper shelf and shelf-slope waters. However, across colonies, females typically preferred depths of <500 m and slopes of <5°. Kleinsee and False Bay seals selected sea surface temperatures within the range typically preferred by pelagic prey species such as round herring, sardine and anchovy (14-19°C). Black Rocks individuals showed bimodal preferences for colder (16°C) and warmer waters (>22°C). Dive behaviour was similar between Kleinsee and False Bay individuals (unavailable from Black Rocks), with both pelagic and benthic foraging evident. Diel patterns were apparent at both sites, as dive depth and benthic diving increased significantly during daylight hours, likely reflecting vertical movements of prey species. We provide the first assessment of Cape fur seal movement behaviour for the South African component of the population. Observed geographic differences likely reflect the availability of suitable habitat but may also indicate differences in foraging strategies and density-dependent effects throughout the range of this species.

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19

David, J. H. M. "Diet of the South African fur seal (1974–1985) and an assessment of competition with fisheries in southern Africa." South African Journal of Marine Science 5, no. 1 (June 1, 1987): 693–713. http://dx.doi.org/10.2989/025776187784522568.

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20

Kirkman, S. P., D. P. Costa, A. L. Harrison, P. G. H. Kotze, W. H. Oosthuizen, M. Weise, J. A. Botha, and J. P. Y. Arnould. "Dive behaviour and foraging effort of female Cape fur seals Arctocephalus pusillus pusillus." Royal Society Open Science 6, no. 10 (October 2019): 191369. http://dx.doi.org/10.1098/rsos.191369.

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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.

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21

Pemberton, David, and Rosemary Gales. "Australian fur seals (Arctocephalus pusillus doriferus) breeding in Tasmania: population size and status." Wildlife Research 31, no. 3 (2004): 301. http://dx.doi.org/10.1071/wr02083.

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This study confirms the persistence of five major breeding colonies of Australian fur seals (Arctocephalus pusillus doriferus) in Tasmanian Bass Strait waters. Incidental births also occasionally occur in very low numbers at other sites. Data collected between 1989 and 1999 shows that estimates of the minimum number of pups born at the major colonies varies considerably between sites and years. No colony has shown a consistent trend in pup production over the last 11 seasons. The most recent count for all Tasmanian colonies for the 1999 breeding season provided a minimum estimate of 3254 pups produced, similar to the estimate of 3373 in 1989. The highest estimate was recorded in 1995 when at least 6024 pups were born. Combining the most recent counts with the numbers estimated for the four Victorian colonies (13 872) gives a minimum pup production of 17 126 for the species, with only one-fifth of all pups being born on Tasmanian islands. Application of population estimators to translate pup numbers to population size for the species results in a conservative estimate of 68 500 individuals with upper and lower bounds of 60 000 and 77 000 Australian fur seals. Numbers of Australian fur seals remain low relative to other fur seal populations, with Australian fur seals being less numerous by an order of magnitude compared with their South African counterpart (A. p. pusillus). The current estimate of the total population of Australian fur seals is approximately half that of pre-sealing levels. The current number of breeding colonies in Tasmania indicates that the population of Australian fur seals breeding in Tasmanian waters has stabilised at well below their historic pre-sealing levels, with at least four sites remaining vacant. The species remains vulnerable due to its small population size, with Tasmanian breeding colonies being particularly vulnerable because of low numbers and due to the profound influence of weather events on pup survival.

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22

Heinrich, Tamara, Andrea Ravignani, and Frederike D. Hanke. "Visual timing abilities of a harbour seal (Phoca vitulina) and a South African fur seal (Arctocephalus pusillus pusillus) for sub- and supra-second time intervals." Animal Cognition 23, no. 5 (May 9, 2020): 851–59. http://dx.doi.org/10.1007/s10071-020-01390-3.

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23

Wickens, Patti. "INTERACTIONS BETWEEN SOUTH AFRICAN FUR SEALS and THE PURSE-SEINE FISHERY." Marine Mammal Science 10, no. 4 (October 1994): 442–57. http://dx.doi.org/10.1111/j.1748-7692.1994.tb00500.x.

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24

Kim, Sunghee, Mats Amundin, and Matthias Laska. "Olfactory discrimination ability of South African fur seals (Arctocephalus pusillus) for enantiomers." Journal of Comparative Physiology A 199, no. 6 (September 26, 2012): 535–44. http://dx.doi.org/10.1007/s00359-012-0759-5.

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25

Laska, Matthias, Elin Lord, Sandra Selin, and Mats Amundin. "Olfactory discrimination of aliphatic odorants in South African fur seals (arctocephalus pusillus)." Journal of Comparative Psychology 124, no. 2 (2010): 187–93. http://dx.doi.org/10.1037/a0018189.

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26

Martin, R. A. "Natural mortality of puffadder shysharks due to Cape fur seals and black-backed kelp gulls at Seal Island, South Africa." Journal of Fish Biology 64, no. 3 (March 2004): 711–16. http://dx.doi.org/10.1111/j.1095-8649.2004.00339.x.

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27

Scheumann, Marina, and Josep Call. "The use of experimenter-given cues by South African fur seals (Arctocephalus pusillus)." Animal Cognition 7, no. 4 (April 1, 2004): 224–30. http://dx.doi.org/10.1007/s10071-004-0216-0.

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28

Crawford, Robert J. M., Benedict L. Dundee, Bruce M. Dyer, Norbert T. W. Klages, Michael A. Meÿer, and Leshia Upfold. "Trends in numbers of Cape gannets (Morus capensis), 1956/1957–2005/2006, with a consideration of the influence of food and other factors." ICES Journal of Marine Science 64, no. 1 (November 2, 2006): 169–77. http://dx.doi.org/10.1093/icesjms/fsl011.

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Abstract Crawford, R. J. M., Dundee, B. L., Dyer, B. M., Klages, N. T., Meÿer, M. A., and Upfold, L. 2007. Trends in numbers of Cape gannets (Morus capensis), 1956/57–2005/06, with a consideration of the influence of food and other factors – ICES Journal of Marine Science, 64, 169–177. Cape gannets (Morus capensis) breed at six colonies in Namibia and South Africa. Population size averaged about 250 000 pairs over the period 1956/1957–1968/1969 and about 150 000 pairs from 1978/1979 to 2005/2006. Over the whole 50-y period, numbers at the three Namibian colonies fell by 85–98%, with greater proportional decreases in the south. There were increases at two South African colonies between 1956/1957 and 2005/2006. The colony at Lambert's Bay increased between 1956/1957 and 2003/2004, but attacks by Cape fur seals (Arctocephalus pusillus) on birds at nests caused abandonment of the entire colony in 2005/2006. Long-term changes at colonies are thought to be largely attributable to an altered abundance and distribution of prey, especially sardine (Sardinops sagax) and anchovy (Engraulis encrasicolus). In both Namibia and South Africa, the numbers of Cape gannets breeding were significantly related to the biomass of epipelagic fish prey. Over the 50-y period, there was also a marked similarity in the proportions of gannets and epipelagic fish in the Benguela system, which were present in Namibia and South Africa. In the 2000s, there was an eastward shift in the distribution of sardine off South Africa and a large increase in the number of gannets breeding at South Africa's easternmost colony. When sardine were scarce off South Africa, gannets fed on anchovy, but off Namibia anchovy only temporarily and partially replaced sardine. Ecosystem management measures that might improve the conservation status of Cape gannets are considered.

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29

Laska, Matthias, Madeleine Svelander, and Mats Amundin. "Successful acquisition of an olfactory discrimination paradigm by South African fur seals, Arctocephalus pusillus." Physiology & Behavior 93, no. 4-5 (March 2008): 1033–38. http://dx.doi.org/10.1016/j.physbeh.2008.01.019.

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30

Hofmeyr, GJG, M. du Toit, and SP Kirkman. "Early post-release survival of stranded Cape fur seal pups at Black Rocks, Algoa Bay, South Africa." African Journal of Marine Science 33, no. 3 (November 2011): 463–68. http://dx.doi.org/10.2989/1814232x.2011.637352.

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31

KASTELEIN, R. A., I. VERHOEVEN, and P. R. WIEPKEMA. "The food consumption of South African fur seals: Arctocephalus pusillus at the Harderwijk Marine Mammal Park." International Zoo Yearbook 29, no. 1 (January 1989): 175–79. http://dx.doi.org/10.1111/j.1748-1090.1989.tb01109.x.

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32

KASTELEIN, R. A., I. VERHOEVEN, and P. R. WIEPKEMA. "The food consumption of South African fur seals: Arctocephalus pusillus at the Harderwijk Marine Mammal Park." International Zoo Yearbook 29, no. 1 (December 18, 2007): 175–79. http://dx.doi.org/10.1111/j.1748-1090.1990.tb03348.x.

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33

Martins, Micaela, Nuno Urbani, Carla Flanagan, Ursula Siebert, Stephanie Gross, Jitender P. Dubey, Luís Cardoso, and Ana Patrícia Lopes. "Seroprevalence of Toxoplasma gondii in Pinnipeds under Human Care and in Wild Pinnipeds." Pathogens 10, no. 11 (October 31, 2021): 1415. http://dx.doi.org/10.3390/pathogens10111415.

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Toxoplasma gondii infection has been reported in numerous species of marine mammals, some of them with fatal consequences. A serosurvey for T. gondii infection was conducted in pinnipeds from an oceanographic park in Portugal (n = 60); stranded pinnipeds on the Portuguese coast (n = 10); and pinnipeds captured in Lorenzensplate, Germany (n = 99). Sera from 169 pinnipeds were tested for the presence of antibodies to T. gondii by the modified agglutination test with a cut-off titre of 25. An overall seroprevalence of 8.9% (95% confidence interval: 5.1–14.2) was observed. Antibody titres of 25, 50, 100, 1600 and ≥3200 were found in five (33.3%), two (13.3%), five (33.3%), one (6.7%) and two (13.3%) animals, respectively. Pinnipeds under human care had a seroprevalence of 20.0% (12/60), in contrast to 2.8% (3/109) in wild pinnipeds (p < 0.001). General results suggest a low exposure of wild pinnipeds to T. gondii, while the seroprevalence found in pinnipeds under human care highlights the importance of carrying out further studies. This is the first serological survey of T. gondii in pinnipeds in Portugal and the first infection report in South African fur seal (Arctocephalus pusillus pusillus).

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34

Hammerschlag, Neil, R. Aidan Martin, and Chris Fallows. "Effects of environmental conditions on predator–prey interactions between white sharks (Carcharodon carcharias) and Cape fur seals (Arctocephalus pusillus pusillus) at Seal Island, South Africa." Environmental Biology of Fishes 76, no. 2-4 (June 3, 2006): 341–50. http://dx.doi.org/10.1007/s10641-006-9038-z.

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Stewardson, C. L. "THE IMPACT OF THE FUR SEAL INDUSTRY ON THE DISTRIBUTION AND ABUNDANCE OF CAPE FUR SEALSARCTOCEPHALUS PUSILLUS PUSILLUSON THE EASTERN CAPE COAST OF SOUTH AFRICA." Transactions of the Royal Society of South Africa 54, no. 2 (January 1999): 217–45. http://dx.doi.org/10.1080/00359199909520626.

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Vrancken, Patrick. "Overview of the Skills Required for Marine Protection and Ocean Governance." South African Journal of Maritime Education and Training 1, no. 1 (2022): 1–7. http://dx.doi.org/10.47348/sajmet/2022/i1a1.

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This paper provides an overview of the skills required for marine protection and ocean governance by focusing on five aspects on a regional basis, namely maritime knowledge, maritime awareness, maritime safety, maritime security and maritime integrity. It is concluded that a focus on the development and retention of the skills required in these regards is necessary for the state to optimally govern the South African maritime domain in the interests of all South Africans, to ensure that South Africa protects its lawful interests on the high seas and to enable South Africa to make its full contribution to the integrated governance of the African maritime domain.

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Guinet, Christophe, Jean Paul Roux, Marielle Bonnet, and Valérie Mison. "Effect of body size, body mass, and body condition on reproduction of female South African fur seals (Arctocephalus pusillus) in Namibia." Canadian Journal of Zoology 76, no. 8 (August 1, 1998): 1418–24. http://dx.doi.org/10.1139/z98-082.

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The relationships between female reproductive parameters (fertility, pregnancy, and lactation status) and body mass, body condition, and body length in South African fur seals (Arctocephalus pusillus) were investigated over 4 years. Ovulation rate in every year was 100% despite interannual differences in female body condition index (BCI). The overall pregnancy rate was 79%. The proportion of pregnant females was related to BCI but not to body mass or body length. In good years, BCI decreased through the first part of the reproductive cycle to a minimum at implantation and increased again through pregnancy. In 1989, BCI declined over the whole reproductive cycle, and there was a higher proportion of nonpregnant females and failures of lactation. Thus, poor nutritional conditions may affect reproductive success through failure to rear a pup, and pup production the following year may also be reduced. This lower rate of pregnancy is partly explained by an increase in the incidence of spontaneous abortions, but other parameters such as a lower implantation rate are also likely to be involved.

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De Vos, Alta, M. Justin O'Riain, Michael A. Meyer, P. Gideon H. Kotze, and Alison A. Kock. "Behavior of Cape fur seals (Arctocephalus pusillus pusillus) in relation to temporal variation in predation risk by white sharks (Carcharodon carcharias)around a seal rookery in False Bay, South Africa." Marine Mammal Science 31, no. 3 (April 1, 2015): 1118–31. http://dx.doi.org/10.1111/mms.12208.

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39

Shaughnessy, Peter D., Catherine M. Kemper, David Stemmer, and Jane McKenzie. "Records of vagrant fur seals (family Otariidae) in South Australia." Australian Mammalogy 36, no. 2 (2014): 154. http://dx.doi.org/10.1071/am13038.

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Two fur seal species breed on the southern coast of Australia: the Australian fur seal (Arctocephalus pusillus doriferus) and the New Zealand fur seal (A. forsteri). Two other species are vagrants: the subantarctic fur seal (A. tropicalis) and the Antarctic fur seal (A. gazella). We document records of vagrant fur seals in South Australia from 1982 to 2012 based primarily on records from the South Australian Museum. There were 86 subantarctic fur seals: 49 specimens and 37 sightings. Most (77%) were recorded from July to October and 83% of all records were juveniles. All but two specimens were collected between July and November. Sightings were prevalent during the same period, but there were also nine sightings during summer (December–February), several of healthy-looking adults. Notable concentrations were near Victor Harbor, on Kangaroo Island and Eyre Peninsula. Likely sources of subantarctic fur seals seen in South Australia are Macquarie and Amsterdam Islands in the South Indian Ocean, ~2700 km south-east and 5200 km west of SA, respectively. There were two sightings of Antarctic fur seals, both of adults, on Kangaroo Island at New Zealand fur seal breeding colonies. Records of this species for continental Australia and nearby islands are infrequent.

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Guinet, Christophe, Jean Paul Roux, Marielle Bonnet, and Valérie Mison. "Effect of body size, body mass, and body condition on reproduction of female South African fur seals (Arctocephalus pusillus) in Namibia." Canadian Journal of Zoology 76, no. 8 (1998): 1418–24. http://dx.doi.org/10.1139/cjz-76-8-1418.

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Shaughnessy, Peter D., Jane McKenzie, Melanie L. Lancaster, Simon D. Goldsworthy, and Terry E. Dennis. "Australian fur seals establish haulout sites and a breeding colony in South Australia." Australian Journal of Zoology 58, no. 2 (2010): 94. http://dx.doi.org/10.1071/zo10017.

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Australian fur seals (Arctocephalus pusillus doriferus) breed on Bass Strait islands in Victoria and Tasmania. They have been recorded in South Australia (SA) for many years as non-breeding visitors and on Kangaroo Island frequently since 1988, mostly in breeding colonies of the New Zealand fur seal (A. forsteri) which is the most numerous pinniped in SA. Australian fur seals have displaced New Zealand fur seals from sections of the Cape Gantheaume colony on Kangaroo Island. North Casuarina Island produced 29 Australian fur seal pups in February 2008. Australian fur seal pups were larger than New Zealand fur seal pups in the same colony and have been identified genetically using a 263-bp fragment of the mitochondrial DNA control region. North Casuarina Island has been an important breeding colony of New Zealand fur seals, but pup numbers there decreased since 1992–93 (contrary to trends in SA for New Zealand fur seals), while numbers of Australian fur seals there have increased. This study confirms that Australian fur seals breed in SA. The two fur seal species compete for space onshore at several sites. Australian fur seals may compete for food with endangered Australian sea lions (Neophoca cinerea) because both are bottom feeders.

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Scharpegge, Julia, Manuel García Hartmann, and Klaus Eulenberger. "THORACIC AUSCULTATION IN CAPTIVE BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS), CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS), AND SOUTH AFRICAN FUR SEALS (ARCTOCEPHALUS PUSILLUS) WITH AN ELECTRONIC STETHOSCOPE." Journal of Zoo and Wildlife Medicine 43, no. 2 (June 2012): 265–74. http://dx.doi.org/10.1638/2011-0022.1.

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Vetter, Walter, Marion Weichbrodt, Elke Scholz, Bernd Luckas, and Herbert Oelschläger. "Levels of Organochlorines (DDT, PCBs, Toxaphene, Chlordane, Dieldrin, and HCHs) in Blubber of South African Fur Seals (Arctocephalus pusillus pusillus) from Cape Cross/Namibia." Marine Pollution Bulletin 38, no. 9 (September 1999): 830–36. http://dx.doi.org/10.1016/s0025-326x(99)00071-5.

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44

Townrow, K., and P. D. Shaughnessy. "Fur seal skull from sealers' quarters at Sandy Bay, Macquarie Island, Southern Ocean." Polar Record 27, no. 162 (July 1991): 245–48. http://dx.doi.org/10.1017/s0032247400012651.

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AbstractFur seals were exterminated from Macquarie Island about 20 years after discovery of the island in 1810. Their specific identity is unknown. Few fur seals were reported at the island until it was occupied by the Australian National Antarctic Research Expeditions in 1948. Fur seal numbers are now increasing. An archaeological excavation at a sealers' quarters at Sandy Bay in 1988 revealed the fragmented skull of a young Antarctic fur sealArctocephalus gazella1.1 m below the surface in a layer dated in the 1870s and 1880s. This period coincides with the recovery of fur seal populations in the South Atlantic Ocean following earlier harvesting. Elsewhere it has been argued that the Antarctic fur seal is unlikely to have been the original fur seal at Macquarie Island because few individuals of that species are ashore in winter, which is the season when the island was discovered and fur-seal harvesting began. It is concluded that the Sandy Bay skull is from a vagrant animal.

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Bamford, Connor C. G., Victoria Warwick-Evans, Iain J. Staniland, Jennifer A. Jackson, and Philip N. Trathan. "Wintertime overlaps between female Antarctic fur seals (Arctocephalus gazella) and the krill fishery at South Georgia, South Atlantic." PLOS ONE 16, no. 3 (March 4, 2021): e0248071. http://dx.doi.org/10.1371/journal.pone.0248071.

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The diet of Antarctic fur seals (Arctocephalus gazella) at South Georgia is dominated by Antarctic krill (Euphausia superba). During the breeding season, foraging trips by lactating female fur seals are constrained by their need to return to land to provision their pups. Post-breeding, seals disperse in order to feed and recover condition; estimates indicate c.70% of females remain near to South Georgia, whilst others head west towards the Patagonian Shelf or south to the ice-edge. The krill fishery at South Georgia operates only during the winter, providing the potential for fur seal: fishery interaction during these months. Here we use available winter (May to September) tracking data from Platform Terminal Transmitter (PTT) tags deployed on female fur seals at Bird Island, South Georgia. We develop habitat models describing their distribution during the winters of 1999 and 2003 with the aim of visualising and quantifying the degree of spatial overlap between female fur seals and krill harvesting in South Georgia waters. We show that spatial distribution of fur seals around South Georgia is extensive, and that the krill fishery overlaps with small, highly localised areas of available fur seal habitat. From these findings we discuss the implications for management, and future work.

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Daneri, Gustavo A., César M. García Esponda, Luciano J. M. De Santis, and Laura Pla. "Skull morphometrics of adult male Antartic fur seal, Arctocephalus gazella, and South American fur seal A. australis." Iheringia. Série Zoologia 95, no. 3 (September 2005): 261–67. http://dx.doi.org/10.1590/s0073-47212005000300006.

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The skull morphometrics of adult male Antarctic fur seal, Arctocephalus gazella (Peters, 1875) and South American fur seal, A. australis (Zimmermann, 1783) were investigated using a collection of 45 and 38 skulls, respectively. Eighteen measurements were taken for each specimen. Comparative univariate and multivariate statistical analyses included standard statistics, one-way analysis of variance, principal component analysis and discriminant analysis. Individual variation was relatively high for some variables, as expressed by the coefficient of variation. Skulls of A. gazella were larger than those of A. australis for all but two variables: squamosal jugal suture and rostral length. Both species differed significantly as shown by both univariate and multivariate analyses. The discriminant function correctly classified all specimens. The standardized canonical coefficients showed that the variables which most contribute to the differentiation between species were, in decreasing order, the rostral length, palatal length, palatal width at postcanine 5 and braincase width. The present study corroborates that A. gazella and A. australis are phenotipically distinct species.

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BONNER, W. NIGEL. "NOTES ON THE SOUTHERN FUR SEAL IN SOUTH GEORGIA." Proceedings of the Zoological Society of London 130, no. 2 (August 20, 2009): 241–52. http://dx.doi.org/10.1111/j.1096-3642.1958.tb00571.x.

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48

Shaughnessy, P. D. "Instances of predation on fur seals by white sharks in South Australia." Australian Mammalogy 28, no. 1 (2006): 107. http://dx.doi.org/10.1071/am06015.

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Shaughnessy, PD, SV Briggs, and R. Constable. "Observations on Seals at Montague Island, New South Wales." Australian Mammalogy 23, no. 1 (2001): 1. http://dx.doi.org/10.1071/am01001.

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Australian fur-seals Arctocephalus pusillus doriferus and New Zealand fur-seals A. forsteri haul-out (come ashore) at the north end of Montague Island. They were counted from study boats on 82 occasions during nine trips to the island, each of about one week, between November 1997 and November 1998, and in July 1999 and April 2000. Highest numbers were recorded between August and October 1998, and more animals were ashore during 1997 and 1998 than Irvine et al. (1997) observed in 1993 and 1994. The maximum number of A. p. doriferus recorded ashore in this study was 540 in October 1998, compared with a little over 300 observed in September 1993. There are reports of a few fur-seal pups on Montague Island. An A. forsteri pup born there in the 1999/2000 summer survived for at least 4 months. Nevertheless, the island should be considered as supporting haul-out sites rather than breeding sites. A Subantarctic fur-seal A. tropicalis and an Australian sea-lion Neophoca cinerea were also recorded during the study. Seven juvenile A. p. doriferus were observed ashore with manmade debris (straps or portions of a trawl net) around their necks. Fur-seals at Montague Island generate interest because of tourism and interactions with local fisheries. Trends in their abundance should be monitored annually in March, for which there is a long-term data set, and in October, when they are most abundant.

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Reinero, Francesca Romana, Emilio Sperone, Gianni Giglio, Antonio Pacifico, Makenna Mahrer, and Primo Micarelli. "Influence of Environmental Factors on Prey Discrimination of Bait-Attracted White Sharks from Gansbaai, South Africa." Animals 12, no. 23 (November 24, 2022): 3276. http://dx.doi.org/10.3390/ani12233276.

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The influence of environmental factors on prey discrimination of bait-attracted white sharks was studied over a six-year period (2008–2013) at Dyer Island Nature Reserve (Gansbaai, South Africa). Across 240 bait-attracted feeding events observed in this period, both immature and mature white sharks were attracted by the seal-shaped decoy rather than the tuna bait, except for the years 2008 and 2011. Tide ranges, underwater visibility, water temperature, and sea conditions were, in decreasing order, the factors which drove white sharks to select the seal-shaped decoy. High tide lowered the minimum depth from which sharks could approach seals close to the shore, while extended visibility helped the sharks in making predatory choices towards the more energy-rich prey source, the odorless seal-shaped decoy. On the contrary, warmer water is associated with an increase in phytoplankton that reduces underwater visibility and increases the diversity of teleosts including tuna—a known prey of white sharks—driving the sharks to favor the tuna bait. Overall, sea conditions were almost always slightly rough, ensuring a good average underwater visibility. Recommendations for future research work at this site are presented.

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