Characterization and causal investigations of an alopecia syndrome in Australian fur seals (<i>Arctocephalus pusillus doriferus</i>)

Lynch, Michael; Kirkwood, Roger; Gray, Rachael; Robson, David; Burton, G.; Jones, Leslie; Sinclair, Rodney; Arnould, John P. Y.

doi:10.1644/11-mamm-a-279.1

Cited by 18 publications

(11 citation statements)

References 61 publications

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“…More recently, research has identified PFAS at high concentrations in pups sampled at Seal Rocks [22]. The adverse health impacts of PFAS are yet to be elucidated but they may affect breeding rates or pup survival through disease and/ or endocrine disruption [27,61]. Also, human-associated antibiotic resistant bacteria have been found at very high levels at Seal Rocks, indicating that exposure to human waste is influential for this site [87].…”

Section: Plos Onementioning

confidence: 99%

Sustained reduction in numbers of Australian fur seal pups: Implications for future population monitoring

McIntosh

Sorrell

Thalmann³

et al. 2022

PLoS ONE

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Fur seal populations in the Southern Hemisphere were plundered in the late 1700s and early 1800s to provide fur for a clothing industry. Millions of seals were killed resulting in potentially major ecosystem changes across the Southern Hemisphere, the consequences of which are unknown today. Following more than a century of population suppression, partly through on-going harvesting, many of the fur seal populations started to recover in the late 1900s. Australian fur seals (Arctocephalus pusillus doriferus), one of the most geographically constrained fur seal species, followed this trend. From the 1940s to 1986, pup production remained at approximately 10,000 per year, then significant growth commenced. By 2007, live pup abundance had recovered to approximately 21,400 per year and recovery was expected to continue However, a species-wide survey in 2013 recorded a 20% decline, to approximately 16,500 live pups. It was not known if this decline was due to 2013 being a poor breeding year or a true population reduction. Here we report the results of a population-wide survey conducted in 2017 and annual monitoring at the most productive colony, Seal Rocks, Victoria that recorded a large decline in live pup abundance (-28%). Sustained lower pup numbers at Seal Rocks from annual counts between 2012–2017 (mean = 2908 ± 372 SD), as well as the population-wide estimate of 16,903 live pups in 2017, suggest that the pup numbers for the total population have remained at the lower level observed in 2013 and that the 5-yearly census results are not anomalies or representative of poor breeding seasons. Potential reasons for the decline, which did not occur range-wide but predominantly in the most populated and long-standing breeding sites, are discussed. To enhance adaptive management of this species, methods for future monitoring of the population are also presented. Australian fur seals occupy several distinct regions influenced by different currents and upwellings: range-wide pup abundance monitoring enables comparisons of ecosystem status across these regions. Forces driving change in Australian fur seal pup numbers are likely to play across other marine ecosystems, particularly in the Southern Hemisphere where most fur seals live.

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Section: Plos Onementioning

confidence: 99%

Sustained reduction in numbers of Australian fur seal pups: Implications for future population monitoring

McIntosh

Sorrell

Thalmann³

et al. 2022

PLoS ONE

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“…Thus, light microscopy and SEM are quite useful ways to identify mammal hair. Results from hair identification keys based on light microscopy and SEM observations have been applied to scientific research in fields, such as taxonomy [ 12 ], ecology [ 2 , 3 , 5 , 7 , 21 ], forensic science [ 11 ] and archeology [ 15 , 19 ]. For example, mammal hair found in the field could be useful for habitat studies of endangered species, as well as the study of feeding habits using scat analysis.…”

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confidence: 99%

Species Identification Key of Korean Mammal Hair

Lee

Choi

Woo

et al. 2014

The Journal of Veterinary Medical Science

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The hair microstructures of Korean terrestrial mammals from 23 species (22 wild and one domestic) were analyzed using light and scanning electron microscopy (SEM) to construct a hair identification key. The hairs were examined using the medulla structures and cuticular scales of guard hairs from the dorsal regions of mature adult animals. All cuticular scale structures in the hair of Rodentia, Lagomorpha, Carnivora and Insectivora showed the petal pattern, and those of Artiodactyla and Chiroptera showed the wave pattern and coronal pattern, respectively. Rodentia, Lagomorpha and Carnivora showed multicellular, and Insectivora and Artiodactyla showed unicellular regular, mesh or columnar in the medulla structures, respectively. Chiroptera did not show the medulla structures in their hair. We found that it is possible to distinguish between species and order based on general appearance, medulla structures and cuticular scales. Thus, we constructed a hair identification key with morphological characteristics from each species. This study suggests that hair identification keys could be useful in fields, such as forensic science, food safety and foraging ecology.

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“…If proper nutrients are not obtained through diet, this can directly impact the body's ability to sustain hair growth (Rushton 2002) or indirectly increase susceptibility to infectious disease (Trites & Donnelly 2003). Juvenile Australian fur seals Arctocephalus pusillus with partial alopecia had significantly lower concentrations of zinc and tyrosine in their fur compared to unaffected individuals (Lynch et al 2012). The authors described breakage in the hair shaft and suggested reduced hair strength was caused by low zinc content.…”

Section: A Factor Of Age Classmentioning

confidence: 99%

“…The authors described breakage in the hair shaft and suggested reduced hair strength was caused by low zinc content. Investigation into variation in diet and foraging areas was suggested by Lynch et al (2012). Similarly, investigation into the nutritional value of prey items and analysis of hair samples for amino acid and mineral composition in juvenile gray seals with and without alopecia is warranted.…”

Section: A Factor Of Age Classmentioning

confidence: 99%

“…Exposure to contaminants, specifically endocrine disruptors, alters hair growth and cell signaling pathways that could impact the hair growth cycle and incite inflammatory responses (Bergman et al 2003, Gregory & Cyr 2003, Novak & Meyer 2009). Observations of alopecia have been linked to contaminant-induced hyperadrenocorticism in Baltic gray seals (Bergman et al 2003) and high levels of heavy metals and persistent organic pollutants in Australian fur seals (Lynch et al 2012). On a more local level, high levels of perfluorochemicals (PFCs) have been measured from the liver of northwest Atlantic harbor seals Phoca vitulina with <1 yr olds having 2.6-fold higher concentration than adult females (Shaw et al 2009).…”

Section: Increase Over Time May Correlate To Changes In Environmentmentioning

confidence: 99%

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Prevalence of alopecia in gray seals Halichoerus grypus atlantica in Massachusetts, USA, 2004-2013

Pugliares-Bonner¹,

McKenna²,

Sette³

et al. 2018

Dis. Aquat. Org.

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There has been an increase in the presence of alopecia among gray seals Halichoerus grypus atlantica in Massachusetts, USA. To understand the prevalence and describe the presentation of this condition, data records and photographs of 10 070 gray seals from 2004−2013 were reviewed; there were sufficient data to confidently assess the presence or absence of alopecia in 2134 seals. Mild hair loss presented in multifocal patches with minimal to no skin lesions or erythema. In severe cases, alopecia was concentrated over the dorsal head, neck, and shoulders and extended down the ventrum, affecting > 50% of the body. Associated skin lesions and erythema were often present. Alopecia was documented in 7.1% of the surveyed seals, and was centered in Nantucket. Alopecia was more prevalent in stranded/sighted animals in spring and summer, with 81% of cases documented from April to July. There was no sex bias, and weanlings were the most affected age class (38%). The etiology for alopecia in Massachusetts gray seals is unknown. Possible causes of alopecia in wildlife are infectious disease, nutritional deficiencies, endo crino pathies, or chronic physiologic stress. High population density around Nantucket may escalate intraspecific competition for resources, which may indirectly lead to stress-induced immuno suppression or nutritional deficiencies. Crowded haul-out sites increase the opportunity for disease transmission. The weanling age class may be prone to alopecia due to naïve immune systems and inexperienced foraging capabilities. Diagnostic sample collection from gray seals will be required to characterize the etiology, pathogenesis, and significance of alopecia in this population.

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Characterization and causal investigations of an alopecia syndrome in Australian fur seals (Arctocephalus pusillus doriferus)

Cited by 18 publications

References 61 publications

Sustained reduction in numbers of Australian fur seal pups: Implications for future population monitoring

Sustained reduction in numbers of Australian fur seal pups: Implications for future population monitoring

Species Identification Key of Korean Mammal Hair

Prevalence of alopecia in gray seals Halichoerus grypus atlantica in Massachusetts, USA, 2004-2013

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