Dietary analysis of regurgitates and stomach samples from free-living Australian sea lions

McIntosh, Rebecca R.; Page, Brad; Goldsworthy, Simon

doi:10.1071/wr06025

Cited by 32 publications

(45 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Limited dietary analysis of Australian sea lions suggests a broad range of prey from crustacean, teleost fish, elasmobranchs, and Little penguins Eudyptula minor spanning several trophic levels (Richardson & Gales 1987, Gales & Cheal 1992, McIntosh et al 2006. This is consistent with our findings of δ 15 N variation spanning almost 3 trophic levels.…”

Section: Individual Long-term Specialisation In Foraging Behavioursupporting

confidence: 82%

Creatures of habit: foraging habitat fidelity of adult female Australian sea lions

Lowther¹,

Harcourt²,

Hamer³

et al. 2011

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

We examined the movement characteristics and seasonality of feeding behaviour for an endemic Australian otariid, the Australian sea lion Neophoca cinerea. By combining tracking data and stable isotope analysis of serially subsampled vibrissae from 20 adult females at 7 colonies, we were able to characterise individual foraging specialisation across 80% of the species range. Adult females expressed long-term temporal consistency in both foraging site (offshore vs. inshore) and prey selection. When seasonality in foraging behaviour was detected (n = 7), there was no consistency in variation of isotope ratios between individuals or colonies. Offshore-foraging sea lions fed at higher trophic levels than inshore foragers. Potentially, inshore foragers could be subdivided into those which targeted heterogeneously distributed seagrass meadows or calcarenite reef sys tems for different payoffs. This data highlights the importance of understanding individual specialisation and the dangers of generalising behaviour at the colony level. Individual specialisation in foraging behaviour may be a mechanism that reduces intra-specific competition, but its effectiveness will be a function of the temporal stability of individual differences. The present study is the first to identify multi-season consistency of individual foraging behaviour for any otariid. Given the long-term stability of adult female foraging behaviour, categorising individuals using a proxy measure such as whisker isotopic signature appears robust, economical, and appropriate. Such data is critical to modelling population response to anthropogenically driven fine-scale habitat modification.

show abstract

Section: Individual Long-term Specialisation In Foraging Behavioursupporting

confidence: 82%

Creatures of habit: foraging habitat fidelity of adult female Australian sea lions

Lowther¹,

Harcourt²,

Hamer³

et al. 2011

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

show abstract

“…Captive Australian sea lions are fed fish with a limited range in terms of both species and size that have been processed through fish markets, while wild sea lions have a broad diet of primarily benthic prey, including octopus (Octopus spp. ), giant cuttlefish (Sepia apama), squid (Sepioteuthis australis), and southern rock lobster (Jasus edwardsii) from inshore to the shelf edge (McIntosh et al 2007;Gibbs et al 2011). The introduction of microbes from unnatural prey may be contributing to variations in microbial diversity in captivity.…”

Section: Discussionmentioning

confidence: 99%

MOLECULAR DETECTION OF ANTIBIOTIC-RESISTANCE DETERMINANTS INESCHERICHIA COLIISOLATED FROM THE ENDANGERED AUSTRALIAN SEA LION (NEOPHOCA CINEREA)

Delport

Harcourt

Beaumont

et al. 2015

Journal of Wildlife Diseases

View full text Add to dashboard Cite

ABSTRACT:Greater interaction between humans and wildlife populations poses significant risks of anthropogenic impact to natural ecosystems, especially in the marine environment. Understanding the spread of microorganisms at the marine interface is therefore important if we are to mitigate adverse effects on marine wildlife. We investigated the establishment of Escherichia coli in the endangered Australian sea lion (Neophoca cinerea) by comparing fecal isolation from wild and captive sea lion populations. Fecal samples were collected from wild colonies March 2009-September 2010 and from captive individuals March 2011-May 2013. Using molecular screening, we assigned a phylotype to E. coli isolates and determined the presence of integrons, mobile genetic elements that capture gene cassettes conferring resistance to antimicrobial agents common in fecal coliforms. Group B2 was the most abundant phylotype in all E. coli isolates (n537), with groups A, B1, and D also identified. Integrons were not observed in E. coli (n521) isolated from wild sea lions, but were identified in E. coli from captive animals (n516), from which class I integrases were detected in eight isolates. Sequencing of gene cassette arrays identified genes conferring resistance to streptomycin-spectinomycin (aadA1) and trimethoprim (dfrA17, dfrB4). Class II integrases were not detected in the E. coli isolates. The frequent detection in captive sea lions of E. coli with resistance genes commonly identified in human clinical cases suggests that conditions experienced in captivity may contribute to establishment. Identification of antibiotic resistance in the microbiota of Australian sea lions provides crucial information for disease management. Our data will inform conservation management strategies and provide a mechanism to monitor microorganism dissemination to sensitive pinniped populations.

show abstract

“…Recent studies observing the influence of diet on gut microbiota of fish and mammalian livestock species have shown that animals that forage manifest greater microbial diversity than those fed from artificial or concentrate sources (47)(48)(49). The varied diet of wild Australian sea lions includes a number of species with chitinous body parts, including small crustaceans, rock lobster, and cephalopods such as cuttlefish, octopus, and squid (27,28). This contrasts with the diet of captive animals, which are fed fresh or frozen fish almost entirely (28).…”

Section: Discussionmentioning

confidence: 99%

“…The varied diet of wild Australian sea lions includes a number of species with chitinous body parts, including small crustaceans, rock lobster, and cephalopods such as cuttlefish, octopus, and squid (27,28). This contrasts with the diet of captive animals, which are fed fresh or frozen fish almost entirely (28). Studies looking at the chitinolytic bacteria in the feces of wild herbivores (50), sheep (51), and humans (52) found that the majority of identified bacteria belonged to the genus Clostridium.…”

Section: Discussionmentioning

confidence: 99%

“…Despite their broad population distribution, both male and female sea lions from individual colonies exhibit strong natal-site philopatry and a tendency for localized foraging (25,26). In the wild, these animals are opportunistic foragers; their diet includes a broad range of shallow-water benthic prey, such as teleost fish, cuttlefish, octopus, squid, rock lobster, rays, small sharks, penguins, and small crustaceans (27,28).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Colony Location and Captivity Influence the Gut Microbial Community Composition of the Australian Sea Lion (Neophoca cinerea)

Delport

Power

Harcourt

et al. 2016

Appl Environ Microbiol

View full text Add to dashboard Cite

Gut microbiota play an important role in maintenance of mammalian metabolism and immune system regulation, and disturbances to this community can have adverse impacts on animal health. To better understand the composition of gut microbiota in marine mammals, fecal bacterial communities of the Australian sea lion (Neophoca cinerea), an endangered pinniped with localized distribution, were examined. A comparison of samples from individuals across 11 wild colonies in South and Western Australia and three Australian captive populations showed five dominant bacterial phyla: Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteria, and Fusobacteria. The phylum Firmicutes was dominant in both wild (76.4% ؎ 4.73%) and captive animals (61.4% ؎ 10.8%), while Proteobacteria contributed more to captive (29.3% ؎ 11.5%) than to wild (10.6% ؎ 3.43%) fecal communities. Qualitative differences were observed between fecal communities from wild and captive animals based on principal-coordinate analysis. SIMPER (similarity percentage procedure) analyses indicated that operational taxonomic units (OTU) from the bacterial families Clostridiaceae and Ruminococcaceae were more abundant in wild than in captive animals and contributed most to the average dissimilarity between groups (SIMPER contributions of 19.1% and 10.9%, respectively). Differences in the biological environment, the foraging site fidelity, and anthropogenic impacts may provide various opportunities for unique microbial establishment in Australian sea lions. As anthropogenic disturbances to marine mammals are likely to increase, understanding the potential for such disturbances to impact microbial community compositions and subsequently affect animal health will be beneficial for management of these vulnerable species. IMPORTANCEThe Australian sea lion is an endangered species for which there is currently little information regarding disease and microbial ecology. In this work, we present an in-depth study of the fecal microbiota of a large number of Australian sea lions from geographically diverse wild and captive populations. Colony location and captivity were found to influence the gut microbial community compositions of these animals. Our findings significantly extend the baseline knowledge of marine mammal gut microbiome composition and variability. It is predicted that global change will have many major, but as yet unknown, impacts on aquatic ecosystems. Marine mammal species, including bottlenose dolphins, sea otters, manatees, and gray whales, have been proposed as sentinels for diverse threats to aquatic health, including disease transmission, changes in food webs, and contaminant levels (1-6). The key roles and contributions of microbes to mammalian host health are becoming increasingly recognized, yet remain largely unexplored for marine mammals (7). An understanding of the impacts of anthropogenic pressures on marine mammal microbial communities and of the potential cascade of impacts on marine health is necessary for full exploration of the roles a...

show abstract

Dietary analysis of regurgitates and stomach samples from free-living Australian sea lions

Cited by 32 publications

References 35 publications

Creatures of habit: foraging habitat fidelity of adult female Australian sea lions

Creatures of habit: foraging habitat fidelity of adult female Australian sea lions

MOLECULAR DETECTION OF ANTIBIOTIC-RESISTANCE DETERMINANTS INESCHERICHIA COLIISOLATED FROM THE ENDANGERED AUSTRALIAN SEA LION (NEOPHOCA CINEREA)

Colony Location and Captivity Influence the Gut Microbial Community Composition of the Australian Sea Lion (Neophoca cinerea)

Contact Info

Product

Resources

About