Arctocephalus Pusillus Research Articles

The cost of a meal: factors influencing prey profitability in Australian fur seals.

Knowledge of the factors shaping the foraging behaviour of species is central to understanding their ecosystem role and predicting their response to environmental variability. To maximise survival and reproduction, foraging strategies must balance the costs and benefits related to energy needed to pursue, manipulate, and consume prey with the nutritional reward obtained. While such information is vital for understanding how changes in prey assemblages may affect predators, determining these components is inherently difficult in cryptic predators. The present study used animal-borne video data loggers to investigate the costs and benefits related to different prey types for female Australian fur seals (Arctocephalus pusillus doriferus), a primarily benthic foraging species in the low productivity Bass Strait, south-eastern Australia. A total of 1,263 prey captures, resulting from 2,027 prey detections, were observed in 84.5 h of video recordings from 23 individuals. Substantial differences in prey pursuit and handling times, gross energy gain and total energy expenditure were observed between prey types. Importantly, the profitability of prey was not significantly different between prey types, with the exception of elasmobranchs. This study highlights the benefit of animal-borne video data loggers for understanding the factors that influence foraging decisions in predators. Further studies incorporating search times for different prey types would further elucidate how profitability differs with prey type.

Predatory species left stranded following the collapse of the sardine Sardinops sagax (Pappe, 1854) stock off the northern Benguela upwelling system: A review

Sardine Sardinops sagax (Pappe, 1854) is an important forage species, in the northern Benguela Upwelling System (nBUS). Sardine was a key forage species of the pelagic component in the nBUS, but the population collapsed due to a combination of overfishing and ecosystem change and variability in the nBUS. Multiple predators depended on sardine as high-quality food at the time when it was abundant. This study reviewed the current knowledge of predators' diet pre- and post-collapse of the sardine population stock in the nBUS. Data were sourced from previous studies on the trophic interaction in the nBUS. The historical and contemporary diets of commercially exploited species that prey on sardine were found to be relatively well documented while there are data deficiencies for non-commercially exploited species including cetaceans, sharks and some non-commercially exploited fish species. Amongst the species most reliant on sardine as prey are African penguin Spheniscus demersus, Cape gannet Morus capensis, Cape cormorant Phalacrocorax capensis, Cape monkfish Lophius vomerinus, shallow-water hake Merluccius capensis, deep-water hake M. paradoxus, snoek Thyrsites atun, Albacore tuna Thunnus alalunga, Cape fur seal Arctocephalus pusillus, Common dolphins Delphinus delphis, Dusky dolphins Lagenorhynchus obscurus, Heaviside's dolphins Cephalorhynchus heavisidii, six gills shark Hexanchus griseus, copper sharks Carcharhinus brachyurus, school shark Galeorhinus galeus and pelagic sharks Prionace glauca. Some predatory species such as the African penguin, Cape cormorant, Cape gannet, and school shark, are considered endangered as per the International Union for the Conservation of Nature (IUCN) Red List criteria. Populations of Albacore tuna and Cape monkfish are near threatened, while Cape fur seals, common dolphins, and shallow-water hake are considered the least concerned on the IUCN list. Although the collapse of sardine has affected the food webs it has not resulted in collapse, rather there have been changes. Three prey species; bearded goby, Cape horse mackerel, and jellyfish, were identified as alternative prey for some of the predators that previously fed on sardine. This review showed how overexploitation of sardine could have had far-reaching effects on the nBUS through feeding linkages. Goby, although a low-quality prey, is a successful substitute for sardine probably mostly due to its high abundance, tolerance to low oxygen and ability to thrive in warm waters. However, further studies are needed to establish the strength of the ecological linkages of the prey species that replaced sardine in the diets of the predators.

Seroprevalence of Toxoplasma gondii in Pinnipeds under Human Care and in Wild Pinnipeds.

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).

Comparative Study of the Gut Microbiota Among Four Different Marine Mammals in an Aquarium.

Despite an increasing appreciation in the importance of host–microbe interactions in ecological and evolutionary processes, information on the gut microbial communities of some marine mammals is still lacking. Moreover, whether diet, environment, or host phylogeny has the greatest impact on microbial community structure is still unknown. To fill part of this knowledge gap, we exploited a natural experiment provided by an aquarium with belugas (Delphinapterus leucas) affiliated with family Monodontidae, Pacific white-sided dolphins (Lagenorhynchus obliquidens) and common bottlenose dolphin (Tursiops truncatus) affiliated with family Delphinidae, and Cape fur seals (Arctocephalus pusillus pusillus) affiliated with family Otariidae. Results show significant differences in microbial community composition of whales, dolphins, and fur seals and indicate that host phylogeny (family level) plays the most important role in shaping the microbial communities, rather than food and environment. In general, the gut microbial communities of dolphins had significantly lower diversity compared to that of whales and fur seals. Overall, the gut microbial communities were mainly composed of Firmicutes and Gammaproteobacteria, together with some from Bacteroidetes, Fusobacteria, and Epsilonbacteraeota. However, specific bacterial lineages were differentially distributed among the marine mammal groups. For instance, Lachnospiraceae, Ruminococcaceae, and Peptostreptococcaceae were the dominant bacterial lineages in the gut of belugas, while for Cape fur seals, Moraxellaceae and Bacteroidaceae were the main bacterial lineages. Moreover, gut microbial communities in both Pacific white-sided dolphins and common bottlenose dolphins were dominated by a number of pathogenic bacteria, including Clostridium perfringens, Vibrio fluvialis, and Morganella morganii, reflecting the poor health condition of these animals. Although there is a growing recognition of the role microorganisms play in the gut of marine mammals, current knowledge about these microbial communities is still severely lacking. Large-scale research studies should be undertaken to reveal the roles played by the gut microbiota of different marine mammal species.

Vocal repertoire, micro-geographical variation and within-species acoustic partitioning in a highly colonial pinniped, the Cape fur seal.

Communication is fundamental for the survival of animal species as signals are involved in many social interactions (mate selection, parental care, collective behaviours). The acoustic channel is an important modality used by birds and mammals to reliably exchange information among individuals. In group-living species, the propagation of vocal signals is limited due to the density of individuals and the background noise. Vocal exchanges are, therefore, challenging. This study is the first investigation into the acoustic communication system of the Cape fur seal (CFS), one of the most colonial mammals with breeding colonies of hundreds of thousands of individuals. We described the acoustic features and social function of five in-air call types from data collected at two colonies. Intra-species variations in these vocalizations highlight a potential ability to convey information about the age and/or sex of the emitter. Using two classification methods, we found that the five call types have distinguishable frequency features and occupy distinct acoustic niches indicating acoustic partitioning in the repertoire. The CFS vocalizations appear to contain characteristics advantageous for discrimination among individuals, which could enhance social interactions in their noisy and confusing acoustic environment. This study provides a basis for our understanding of the CFS acoustic communication system.

Influence of environmental variation on spatial distribution and habitat-use in a benthic foraging marine predator.

The highly dynamic nature of the marine environment can have a substantial influence on the foraging behaviour and spatial distribution of marine predators, particularly in pelagic marine systems. However, knowledge of the susceptibility of benthic marine predators to environmental variability is limited. This study investigated the influence of local-scale environmental conditions and large-scale climate indices on the spatial distribution and habitat use in the benthic foraging Australian fur seal (Arctocephalus pusillus doriferus; AUFS). Female AUFS provisioning pups were instrumented with GPS or ARGOS platform terminal transmitter tags during the austral winters of 2001–2019 at Kanowna Island, south-eastern Australia. Individuals were most susceptible to changes in the Southern Oscillation Index that measures the strength of the El Niño Southern Oscillation, with larger foraging ranges, greater distances travelled and more dispersed movement associated with 1-yr lagged La Niña-like conditions. Additionally, the total distance travelled was negatively correlated with the current year sea surface temperature and 1-yr lagged Indian Ocean Dipole, and positively correlated with 1-yr lagged chlorophyll-a concentration. These results suggest that environmental variation may influence the spatial distribution and availability of prey, even within benthic marine systems.

Entanglement of Cape fur seals (Arctocephalus pusillus pusillus) at colonies in central Namibia

Marine pollution is increasing, and pinnipeds are commonly affected by entanglement in waste. We investigated entanglement rates, common materials, and the demographic profile of Cape fur seals (Arctocephalus pusillus pusillus) affected at two Namibian colonies. Overall, we identified 366 cases of entanglement, and present a global rate of entanglement of 0.17%. Entanglement rates were 0.17% and 0.15% for the Pelican Point and Cape Cross colonies, respectively. We identified 17% more entanglements through photographs than binocular scans. Of the 347 entanglements analysed in detail, juveniles were most commonly affected and fishing materials were the primary cause of entanglements (53%), with 8% of entangled seals exhibiting ‘very severe’ injuries. Overall, 191 individuals were successfully disentangled, and citizen scientists contributed 51% of total entanglement data. We highlight the negative impact of plastic marine waste among seals and the importance of disentanglement for individual animal welfare.

Extreme ecological constraints lead to high degree of individual stereotypy in the vocal repertoire of the Cape fur seal (Arctocephalus pusillus pusillus)

The ability to recognize the identity of conspecifics is a key component for survival of many animal species and is fundamental to social interactions such as parental care, intra-sexual competition or mate recognition. In group-living species, the simultaneous co-existence of many individuals increases the number of interactions and reinforces the need for individual recognition. Acoustic signals are widely used by birds and mammals to communicate and to convey information about identity, but their use in very dense colonies becomes challenging due to the high level of background noise and the high risk of confusion among individuals. The Cape fur seal (CFS) is the most colonial pinniped species and one of the most colonial mammals in the world, with colonies of up to 210,000 individuals during the breeding season. Here, we investigated the individual stereotypy in vocalizations produced by pups, females and male CFS using Random Forests and index of vocal stereotypy (IVS). We thus compared IVS values of CFS to other pinniped species. Within CFS we identified individuality in all call types but the degree of individual stereotypy varies in regard to their social function: affiliative calls produced in a mother–pup reunion context and territorial calls produced by mature bulls holding harem were more individualized than vocalizations involved in agonistic interactions. Our inter-species comparisons among pinnipeds showed that CFS affiliative and territorial calls displayed higher degrees of individuality compared to other species with similar or lower ecological constraints (colony density and social structure). Individual recognition is primordial for the establishment of social interactions and notably occurs through acoustic signals in many birds and mammalian species. Understanding the role of social complexity in the development of individual vocal recognition improves our general knowledge on acoustic communication in a social system. This study investigated the vocal stereotypy in the Cape fur seal (CFS), a species that is an extreme illustration of social complexity. The CFS is the most colonial pinniped species, and this results in high selective pressure for individual recognition during mother–pup reunions and male territorial behaviour. By comparing the degree of individuality contained in CFS vocalizations with other pinniped species, we can assess how ecological (environmental and social) constraints drive communication systems in vertebrates.

Disentanglement of Cape fur seals (Arctocephalus pusillus pusillus) with reversible medetomidine-midazolam-butorphanol.

Anaesthesia in pinnipeds is considered a much higher risk than in most terrestrial mammals because of their frequent proximity to water and physiological and anatomical adaptations related to diving, which also influence their anaesthesia management. Anaesthetising and immobilising entangled seals does not allow for selection of animals that are at a safe distance from the water’s edge. Medetomidine-midazolam-butorphanol (MMB) sedation was trialled on eight entangled Cape fur seals (CFS) (Arctocephalus pusillus pusillus) to determine if it was safe to use on animals that entered the water post-darting. The MMB was given at an estimated dose of 0.03 mg/kg, 0.2 mg/kg and 0.2 mg/kg, respectively, via remote darting. Sedation was reversed with intramuscular atipamezole (0.15 mg/kg) and naltrexone (0.4 mg/kg) to antagonise the effects of medetomidine and butorphanol, respectively. Moderate sedation was achieved in six animals. Six of the animals entered the water after being darted. There was a single mortality and a single animal that was too lightly sedated for capture. The preliminary results indicate that MMB produces suitable sedation for disentanglement of CFS. Additionally, MMB might be suitable for application to field-based biological research.

Machine learning to detect marine animals in UAV imagery: effect of morphology, spacing, behaviour and habitat

AbstractMachine learning algorithms are being increasingly used to process large volumes of wildlife imagery data from unmanned aerial vehicles (UAVs); however, suitable algorithms to monitor multiple species are required to enhance efficiency. Here, we developed a machine learning algorithm using a low‐cost computer. We trained a convolutional neural network and tested its performance in: (1) distinguishing focal organisms of three marine taxa (Australian fur seals, loggerhead sea turtles and Australasian gannets; body size ranges: 0.8–2.5 m, 0.6–1.0 m, and 0.8–0.9 m, respectively); and (2) simultaneously delineating the fine‐scale movement trajectories of multiple sea turtles at a fish cleaning station. For all species, the algorithm performed best at detecting individuals of similar body length, displaying consistent behaviour or occupying uniform habitat (proportion of individuals detected, or recall of 0.94, 0.79 and 0.75 for gannets, seals and turtles, respectively). For gannets, performance was impacted by spacing (huddling pairs with offspring) and behaviour (resting vs. flying shapes, overall precision: 0.74). For seals, accuracy was impacted by morphology (sexual dimorphism and pups), spacing (huddling and creches) and habitat complexity (seal sized boulders) (overall precision: 0.27). For sea turtles, performance was impacted by habitat complexity, position in water column, spacing, behaviour (interacting individuals) and turbidity (overall precision: 0.24); body size variation had no impact. For sea turtle trajectories, locations were estimated with a relative positioning error of &lt;50 cm. In conclusion, we demonstrate that, while the same machine learning algorithm can be used to survey multiple species, no single algorithm captures all components optimally within a given site. We recommend that, rather than attempting to fully automate detection of UAV imagery data, semi‐automation is implemented (i.e. part automated and part manual, as commonly practised for photo‐identification). Approaches to enhance the efficiency of manual detection are required in parallel to the development of effective implementation of machine learning algorithms.

Per and polyfluoroalkyl substances (PFAS) at high concentrations in neonatal Australian pinnipeds

Per and polyfluorinated substances (PFAS) exposure was investigated in Australian pinnipeds. Concentrations of 16 PFAS were measured in the livers of Australian sea lion (Neophoca cinerea), Australian fur seal (Arctocephalus pusillus doriferus) and a long-nosed Fur Seal (Arctocephalus forsteri) pup sampled between 2017 and 2020 from colonies in South Australia and Victoria. Findings reported in this study are the first documented PFAS concentrations in Australian pinnipeds.Median and observed range of values in ng/g wet weight were highest for perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) in the liver of N. cinerea (PFOS = 7.14, 1.00–16.9; PFOA = 2.73, 0.32–11.2; PFNA = 2.96, 0.61–8.22; n = 28), A. forsteri (PFOS = 15.98, PFOA = 2.02, PFNA = 7.86; n = 1) and A. p. doriferus (PFOS = 27.4, 10.5–2119; PFOA = 0.98, 0.32–52.2; PFNA = 2.50, 0.91–44.2; n = 20). PFAS concentrations in A. p. doriferus pups were significantly greater (p < 0.05) than in N. cinerea pups for all PFAS except PFOA and were of similar magnitude to those reported in northern hemisphere marine animals. These results demonstrate exposure differences in both magnitude and PFAS profiles for N. cinerea in South Australia and A. p. doriferus in Victoria.This study reports detectable PFAS concentrations in Australian pinniped pups indicating the importance of maternal transfer of these toxicants. As N. cinerea are endangered and recent declines in pup production has been reported for A. p. doriferus at the colony sampled, investigation of potential health impacts of these toxicants on Australian pinnipeds is recommended.

Protected area use by two sympatric marine predators repopulating their historical range

As large carnivores recover from over-exploitation, managers often lack evidence-based information on species habitat requirements and the efficacy of management practices, particularly where species repopulate areas from which they have long been extirpated. We investigated the movement and habitat use by 2 semi-aquatic carnivores (Australian fur seals Arctocephalus pusillus doriferus and New Zealand fur seals A. forsteri) at the northern end of their distributions in Australia, where after a long absence both are recolonising their historic range. We also assessed male fur seal habitat use overlap with terrestrial and marine protected areas (PAs). While at the margin of the range during winter and early spring, the males remained inshore close to terrestrial sites and where interactions with humans often occur. From early spring, the males from the range margin showed uniform movement toward colonies in the core of the species’ range prior to their breeding seasons. This contrasts with males tracked from the core of the species’ range that returned periodically to colonies during the year, and highlights the importance of range-wide monitoring of a species to inform conservation planning. Habitat use by some males included over 90% of a marine PA at the margin of the species’ range. Most terrestrial haul-outs used were within terrestrial PAs, while sites not protected were on the margin of the range. Despite wide-ranging habits, their dependence on coastal sites, where human access and activities can be regulated and more readily enforced, suggests that terrestrial and marine PAs will continue to play an important role in managing the recovery of these fur seals.

Feel the beat Cape fur seal males encode their arousal state in their bark rate

Feel the beat Cape fur seal males encode their arousal state in their bark rate

Intertrip consistency in hunting behavior improves foraging success and efficiency in a marine top predator.

Substantial variation in foraging strategies can exist within populations, even those typically regarded as generalists. Specializations arise from the consistent exploitation of a narrow behavioral, spatial or dietary niche over time, which may reduce intraspecific competition and influence adaptability to environmental change. However, few studies have investigated whether behavioral consistency confers benefits at the individual and/or population level. While still recovering from commercial sealing overexploitation, Australian fur seals (AUFS; Arctocephalus pusillus doriferus) represent the largest marine predator biomass in south‐eastern Australia. During lactation, female AUFS adopt a central‐place foraging strategy and are, thus, vulnerable to changes in prey availability. The present study investigated the population‐level repeatability and individual consistency in foraging behavior of 34 lactating female AUFS at a south‐east Australian breeding colony between 2006 and 2019. Additionally, the influence of individual‐level behavioral consistency on indices of foraging success and efficiency during benthic diving was determined. Low to moderate population‐level repeatability was observed across foraging behaviors, with the greatest repeatability in the mean bearing and modal dive depth. Individual‐level consistency was greatest for the proportion of benthic diving, total distance travelled, and trip duration. Indices of benthic foraging success and efficiency were positively influenced by consistency in the proportion of benthic diving, trip duration and dive rate but not influenced by consistency in bearing to most distal point, dive depth or foraging site fidelity. The results of the present study provide evidence of the benefits of consistency for individuals, which may have flow‐on effects at the population level.

Extreme ecological constraints lead to high degree of individual stereotypy in the vocal repertoire of the Cape fur seal (Arctocephalus pusillus pusillus)

Extreme ecological constraints lead to high degree of individual stereotypy in the vocal repertoire of the Cape fur seal (Arctocephalus pusillus pusillus)

Corynosoma australe and Bolbosoma vasculosum (Polymorphidae: Acanthocephala) from Arctocephalus pusillus pusillus (Otariidae) and Argyrosomus spp. (Sciaenidae) from the Namibian Coast of Africa

Five Cape fur seals, Arctocephalus pusillus pusillus, 1 dusky kob, Argyrosomus coronus, and 55 silver kob, A. inodorus, collected from Cape Cross, Henties Bay, and Skeleton Coast Park, Namibia, were examined for acanthocephalans. Adults of Bolbosoma vasculosum and Corynosoma australe were recovered from 5 Cape fur seals, and cystacanths of C. australe from the single dusky kob and 3 of the silver kobs that were examined. This is the first record of B. vasculosum and the second of C. australe from the Namibian coast. Scanning electron microscopy of specimens of C. australe revealed features such as bursal papillae and micropores both on the proboscis hook surfaces and across the epidermal surface of the trunk. X-ray analyses of gallium cut hook, egg, and spines of C. australe are presented with analyses of spines of Corynosoma strumosum for comparison.

Environmental influences on foraging effort, success and efficiency in female Australian fur seals

Understanding the factors which influence foraging behaviour and success in marine mammals is crucial to predicting how their populations may respond to environmental change. The Australian fur seal (Arctocephalus pusillus doriferus, AUFS) is a predominantly benthic forager on the shallow continental shelf of Bass Strait, and represents the greatest biomass of marine predators in south-eastern Australia. The south-east Australian region is experiencing rapid oceanic warming, predicted to lead to substantial alterations in prey diversity, distribution and abundance. In the present study, foraging effort and indices of foraging success and efficiency were investigated in 138 adult female AUFS (970 foraging trips) during the winters of 1998–2019. Large scale climate conditions had a strong influence on foraging effort, foraging success and efficiency. Foraging effort and foraging success were also strongly influenced by winter chlorophyll-a concentrations and sea-surface height anomalies in Bass Strait. The results suggest increasing foraging effort and decreasing foraging success and efficiency under anticipated environmental conditions, which may have population-level impacts.

Geographic variation in at-sea movements, habitat use and diving behaviour of female Cape fur seals

Knowledge of animal foraging behaviour has implications for management and conservation. While Cape fur sealsArctocephalus pusillus pusilluscomprise 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 &lt;500 m and slopes of &lt;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 (&gt;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.

Diversity and Distribution of Escherichia coli in Three Species of Free-Ranging Australian Pinniped Pups

Anthropogenic activities and pollution are impacting marine environments globally. This has resulted in increasing numbers of human-associated phylotypes of Escherichia coli, an indicator of faecal contamination, being found in both aquatic environments and upper trophic marine mammals that are considered sentinels for marine health. The objective of this study was to determine the presence and diversity of E. coli in pups of three species of free-ranging pinnipeds in Australia. Faecal samples (n = 964) were collected between 2016 and 2019 from Australian sea lion (Neophoca cinerea), Australian fur seal (Arctocephalus pusillus doriferus) and long-nosed fur seal (Arctocephalus forsteri) pups from eight breeding colonies extending along the Southern Australian coast. E. coli were isolated from 842 (87.3%) samples and molecular screening was applied to assign isolates to E. coli phylotypes and sub-types. The human associated E. coli phylotype B2 was the most frequently isolated in all species at seven of the eight colonies, with 73.7% of all E. coli isolates belonging to this phylotype. Phylotype distribution did not differ significantly within or across species, breeding colonies or breeding seasons. Further analysis of B2 isolates into sub-types showed a significant difference in sub-type distribution across breeding seasons at two colonies (Seal Rocks and Cape Gantheaume). The predominance of the B2 phylotype could indicate that all colonies are exposed to similar levels of anthropogenic pollution. This widespread occurrence of the human-associated E. coli phylotypes highlights the imperative for ongoing monitoring and surveillance of microbes in both the marine environment and sentinel species.

Dentigerous cyst in a South African fur seal (Arctocephalus pusillus pusillus)

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.