ORCID Profile
0000-0003-4221-4050
Current Organisations
University of Tasmania
,
SARDI - Aquatic Sciences
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Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/WR06094
Abstract: Cabergoline is a potent inhibitor of prolactin release and a potential fertility control agent for foxes. To understand how cabergoline could behave in baits deployed for fox control, we conducted laboratory and field trials to investigate the stability of cabergoline when (1) in solution, (2) injected into a bait (deep-fried liver and Foxoff®) and (3) exposed to a range of environmental conditions, including burial. Cabergoline, dissolved in a 1% acetic acid solution, and its carboxylic acid hydrolysis product can be assayed using high-performance liquid chromatography. When stored at 4°C and at room temperature, cabergoline in solution was stable for up to 36 days. When stored under cool (≤15°C), dry conditions, cabergoline (800 µg) in commercial Foxoff® and deep-fried ox-liver baits was stable for 28 and 7 days, respectively stability was reduced by increases in temperature (tested up to 40°C) and humidity. Recovery of cabergoline from buried baits exposed to a range of field conditions decreased rapidly in the first week, but after 56 days remained detectable at levels of 6–22% of the injected amounts. This study has important implications for baiting c aigns that use cabergoline for fox control.
Publisher: American Geophysical Union (AGU)
Date: 21-10-2019
DOI: 10.1029/2019GL084347
Abstract: The emperor penguin, an iconic species threatened by projected sea ice loss in Antarctica, has long been considered to forage at the fast ice edge, presumably relying on large/yearly persistent polynyas as their main foraging habitat during the breeding season. Using newly developed fine‐scale sea icescape data and historical penguin tracking data, this study for the first time suggests the importance of less recognized small openings, including cracks, flaw leads and ephemeral short‐term polynyas, as foraging habitats for emperor penguins. The tracking data retrieved from 47 emperor penguins in two different colonies in East Antarctica suggest that those penguins spent 23% of their time in ephemeral polynyas and did not use the large/yearly persistent, well‐studied polynyas, even if they occur much more regularly with predictable locations. These findings challenge our previous understanding of emperor penguin breeding habitats, highlighting the need for incorporating fine‐scale seascape features when assessing the population persistence in a rapidly changing polar environment.
Publisher: Wiley
Date: 07-2003
Publisher: Elsevier BV
Date: 2014
Publisher: Inter-Research Science Center
Date: 07-2021
DOI: 10.3354/ESR01129
Abstract: 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.
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/WR02057
Abstract: This study aimed to adapt M-44 ejectors for use in sandy soils and to assess the feasibility of incorporating the modified M-44s into a long-term fox-control program on Phillip Island, Victoria. M-44s were adapted by burying a plastic cylinder around them, which prevented sandy soil from collapsing and inhibiting the trigger mechanism, and at the same time orientated the fox's mouth vertically over the M-44 to maximise the dose of poison delivered. The fast-acting poison sodium cyanide was used to ensure the collection of fox bodies and any non-target animals. A fox was killed on 78.6% of occasions that an M-44 was triggered. No non-target species triggered M-44s, although rodents and birds occasionally ate the unpoisoned baits. The modified M-44 ejector technique accounted for 19% of foxes killed by all techniques during one year on Phillip Island. To assess whether M-44s were a worthwhile technique to include in the fox-control program on Phillip Island, we compared their catch per unit effort (number of foxes killed per 1000 person-hours) with other control techniques (spotlight shooting, treadle snaring and hunting with fox hounds). Deployment of M-44s with cyanide was labour intensive, due to safety considerations, and cyanide can be used only as a research tool. Future management use of the M-44s would be with sodium monofluoroacetate (1080), so an estimate was made of the catch per unit effort of M-44s with this poison. Results suggest that deployment of M-44s with 1080 is likely to be more time-effective than the other techniques.
Publisher: Oxford University Press (OUP)
Date: 15-04-2011
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/WR04039
Abstract: The day roosting behaviour of the little forest bat (Vespadelus vulturnus), Australia’s smallest bat, was investigated in the context of the planned removal of dead timber within managed woodlands on Phillip Island, Victoria. Between August 1999 and March 2000, 14 female little forest bats were fitted with VHF microtransmitters and tracked to a total of 16 roost trees. All roosts were located in dead timber, 11 in severely decayed remains of eucalypt trees, and five in dead sections of live trees. Roost trees were compared with randomly chosen trees from within the available habitat, for a range of tree characteristics. Female little forest bats selected roosts in trees with dead timber offering many hollows and reduced canopy cover. Furthermore, roost trees were located in areas (0.1-ha plots) with higher densities of these types of trees than in the available habitat. However, there was no difference in the height or diameter of roost trees or roost plots compared with available habitat. Emergence time from roosts was strongly associated with civil twilight (when the centre of the sun is 6° below an ideal horizon), and the number of bats exiting a single roost tree ranged from 1 to 120 (median = 20). Dead trees provide critical roosting habitat and we recommend retention of dead standing trees for conserving little forest bat roosts in managed woodlands.
Publisher: CSIRO Publishing
Date: 2000
DOI: 10.1071/WR99046
Abstract: The abundance of Australian fur seal pups was determined at Seal Rocks, Westernport, Victoria in late December 1997 using a mark–recapture procedure with repeated recapture sessions. Pups (n = 1291) were marked by clipping the black guard hair on the head to reveal lighter underfur. Recaptures from the whole colony were made on eight occasions 1–3 days later. In the recapture sessions, a mean of 32% of sighted pups had been marked. Estimates of pup numbers over the eight recapture sessions were calculated using the Petersen estimate and then combined by taking their arithmetic mean. The combined estimate was 4024 (95% confidence range 3908–4141). In 1991–92, a similar procedure led to an estimate of pup numbers of 2817 (95% confidence range 2703–2930). For both breeding seasons, estimates of pup numbers from each recapture session were also combined assuming a joint hypergeometric distribution there was little difference in the results from the two procedures, although the confidence intervals for the hypergeometric mean were smaller than those for the arithmetic mean. From 1991–92 to 1997–98, pup numbers increased by 43%, at an exponential rate of 0.059 (95% confidence range 0.0526–0.0664), equivalent to 6.1% per annum (5.4–6.9%). This is greater than the rate of increase of pups at the colony between 1968–69 and 1991–92, which was 0.023 (95% confidence range 0.0198–0.0268), equivalent to 2.4% per annum (2.0–2.7%). Because of the rapid rate of increase of the Australian fur seal colony at Seal Rocks and the importance of the locality for tourism, we recommend that the abundance of pups there be determined every 3–5 years using a mark–recapture technique.
Publisher: Springer Science and Business Media LLC
Date: 19-07-2007
Publisher: Wiley
Date: 12-2007
DOI: 10.1002/AQC.908
Publisher: Springer Science and Business Media LLC
Date: 1989
DOI: 10.1007/BF00391967
Publisher: University of Chicago Press
Date: 1997
DOI: 10.1086/639535
Abstract: Captive emperor penguins in Antarctica hand-fed Antarctic krill assimilated an average of 70.5% +/- 1.7% (n = 3) of the energy in the diet. Water intake estimated by tritiated water turnover was 9.4% +/- 2.4% less than that measured gravimetrically. Tritium took 1.5 h from injection to equilibrate with the penguins' body water pools.
Publisher: Wiley
Date: 04-2009
Publisher: Wiley
Date: 04-2005
Publisher: Cold Spring Harbor Laboratory
Date: 08-03-2018
DOI: 10.1101/267567
Abstract: Historic hunting has led to severe reductions of many marine mammal species across the globe. After hunting ceased, some populations have recovered to pre-exploitation levels, and may again act as a top-down regulatory force on marine ecosystems. Also the harbour seal population in the international Wadden Sea grew at an exponential rate following a ban on seal hunting in 1960’s, and the current number ∼38,000 is close to the historic population size. Here we estimate the impact of the harbour seal predation on the fish community in the Wadden Sea and nearby coastal waters. Fish remains in faecal s les and published estimates on the seal’s daily energy requirement were used to estimate prey selection and the magnitude of seal consumption. Estimates on prey abundance were derived from demersal fish surveys, and fish growth was estimated using a Dynamic Energy Budget model. GPS tracking provided information on where seals most likely caught their prey. Harbour seals from the Dutch Wadden Sea fed predominantly on demersal fish, e.g. flatfish species (flounder, sole, plaice, dab), but also sandeel, cod and whiting. Total fish biomass in the Wadden Sea was insufficient to sustain the estimated prey consumption of the entire seal population year-round. This probably explains why seals also acquire prey further offshore in the adjacent North Sea, only spending 13% of their ing time in the Wadden Sea. Still, seal predation was estimated to cause an average annual mortality of 43% and 60% on fish in the Wadden Sea and adjacent coastal zone, respectively. There were however large sources of uncertainty in the estimate, including the migration of fish between the North Sea and Wadden Sea, and catchability estimates of the fish survey s ling gear, particularly for sandeel and other pelagic fish species. Our estimate suggested a considerable top-down control by harbour seals on demersal fish. However predation by seals may also alleviate density-dependent competition between the remaining fish, increasing fish growth, and partly compensating for the reduction in fish numbers. This study shows that recovering coastal marine mammal populations could potentially become an important component in the functioning of shallow coastal systems.
Publisher: Springer Science and Business Media LLC
Date: 18-03-2020
DOI: 10.1038/S41597-020-0406-X
Abstract: The Retrospective Analysis of Antarctic Tracking Data (RAATD) is a Scientific Committee for Antarctic Research project led jointly by the Expert Groups on Birds and Marine Mammals and Antarctic Bio ersity Informatics, and endorsed by the Commission for the Conservation of Antarctic Marine Living Resources. RAATD consolidated tracking data for multiple species of Antarctic meso- and top-predators to identify Areas of Ecological Significance. These datasets and accompanying syntheses provide a greater understanding of fundamental ecosystem processes in the Southern Ocean, support modelling of predator distributions under future climate scenarios and create inputs that can be incorporated into decision making processes by management authorities. In this data paper, we present the compiled tracking data from research groups that have worked in the Antarctic since the 1990s. The data are publicly available through bio ersity.aq and the Ocean Biogeographic Information System. The archive includes tracking data from over 70 contributors across 12 national Antarctic programs, and includes data from 17 predator species, 4060 in idual animals, and over 2.9 million observed locations.
Publisher: Pensoft Publishers
Date: 18-12-2018
DOI: 10.3897/NATURECONSERVATION.31.26263
Abstract: In Australia, a multi-million-dollar industry is based on viewing the Australian fur seal ( Arctocephaluspusillusdoriferus ), predominantly through boat visits to breeding colonies. Regulation of boat approaches varies by site and no systematic investigations have been performed to inform management guidelines. To investigate possible effects of disturbance, experimental boat approaches were made to a colony at Kanowna Island in northern Bass Strait and seal responses were monitored using instantaneous scan s ling. Colony attendance (in iduals remaining ashore) was found to be influenced by approach distance and time of day, but was not affected by environmental variables or season, whereas onshore resting behavior was influenced by approach distance, time of day, ambient temperature and wind direction. Onshore resting behavior decreased following experimental boat approaches to 75 m, but changes in abundance of in iduals ashore were not observed at this distance. In contrast, approaches to 25 m elicited a strong response, with a steep decline in the number of in iduals ashore. This response was strongest when approaches occurred in the morning, with a decline of approximately 47% of in iduals, compared to a decline of 21% during afternoon approaches. With regard to onshore resting behavior, afternoon approaches to 75 m led to minimal response. The remaining three combinations of approach distance and time of day had a similar pattern of reductions in the proportion of in iduals engaging in onshore resting behavior. The strongest response was again seen during approaches to 25 m conducted in the morning. These behavior changes suggest that unrestricted boat-based ecotourism at Australian fur seal colonies has the potential to increase energy expenditure and reduce the number of seals ashore. Increasing minimum approach distances to ≥75 m and/or restricting visits to afternoons may minimize these impacts at Kanowna Island during the post-molt and non-breeding seasons. As several studies have demonstrated considerable intra-species variation in seal responses to boat approaches, research at other colonies is needed before these findings can be generalized to the remainder of the Australian fur seal population.
Publisher: Wiley
Date: 17-04-2009
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/AM05089
Abstract: THE introduction of feral cats (Felis catus) and red foxes (Vulpes vulpes) to Australia in the 1800s had a profound impact on resident ecosystems. Both predators colonised successfully and now are distributed across most of mainland Australia (Saunders et al. 1995 Abbott 2002). They consume mainly ground-dwelling mammals (Coman 1973 Croft and Hone 1978 Jones and Coman 1981 Lapidge and Henshall 2002 Hutchings 2003), but where these are scarce, birds, reptiles, insects and human refuse may become important dietary components (e.g., Bubela et al. 1998 Paltridge 2002). Although they prey on similar species, when compared at the same location differences in diet between the predators are evident (Triggs et al. 1984 Catling 1988 Risbey et al. 1999).
Publisher: Wildlife Disease Association
Date: 1995
DOI: 10.7589/0090-3558-31.1.83
Abstract: Tuberculosis was found in a wild, mature male Australian fur seal (Arctocephalus pusillus doriferus) at Hobart, Tasmania on 8 March 1992. We observed fibrogranulomatous and pyogranulomatous lesions in the lung, pleura, lymph nodes and spleen. The SDS/PAGE profile of this Tasmanian isolate was similar to other seal strains however, differences were detected using pTBN12 and insertion sequence IS6110 probes.
Publisher: SAGE Publications
Date: 11-2011
Abstract: Bacteria from the genus Mycoplasma are common inhabitants of the respiratory, gastrointestinal, and genital tracts of mammals. The understanding of the pathological significance of mycoplasmas in seals is poor, as few studies have utilized the specific culture techniques required to isolate these bacteria. The current study surveyed for the Mycoplasma species present in Australian fur seals ( Arctocephalus pusillus doriferus) and investigated the association between infection and pathology. Mycoplasmas were found in the nasal cavities of 55/80 (69%) of apparently healthy in iduals. Isolates from 18 in iduals were investigated through 16S ribosomal RNA sequencing, and 3 species were identified: M. zalophi, M. phocae, and Mycoplasma sp. (GenBank no. EU714238.1), all of which had previously been isolated from Northern Hemisphere pinnipeds. In addition, mycoplasmas were isolated from the lungs of 4 out of 16 juveniles and 1 out of 5 adults s led at necropsy. Isolates obtained were M. zalophi, Mycoplasma sp. EU714238.1, and M. phocicerebrale, but infection was not associated with lung pathology in these age classes. Inflammatory disease processes of the heart and/or lungs were present in 12 out of 32 (38%) aborted fetuses on microscopic examination. Predominant findings were interstitial pneumonia, pericarditis, and myocarditis. Mycoplasma phocicerebrale was isolated from the thymus of an aborted fetus, and 3 out of 11 (27%) fetuses with inflammatory heart or lung lesions were PCR-positive for Mycoplasma. In conclusion, several species of Mycoplasma are part of the normal flora of the nasal cavity of Australian fur seals, and some mycoplasmas may be associated with abortion in this species of seal.
Publisher: Wiley
Date: 11-2010
DOI: 10.2193/2009-482
Publisher: Inter-Research Science Center
Date: 18-01-2008
DOI: 10.3354/ESR00069
Publisher: Wildlife Disease Association
Date: 04-2011
DOI: 10.7589/0090-3558-47.2.352
Abstract: Novel members of the bacterial genus Brucella have recently emerged as pathogens of various marine mammal species and as potential zoonotic agents. We investigated the epizootiology of Brucella infection in Australian fur seals (Arctocephalus pusillus doriferus) by establishing demographic and temporal variations in antibody prevalence, attempting isolation of the causative agent, and determining whether this potential pathogen is involved in frequent abortions observed in this pinniped species. Two competitive enzyme-linked immunosorbent assays (cELISAs), an indirect ELISA, and a fluorescence polarization assay (FPA) were used to test sera for Brucella antibodies. The FPA and cELISA proved suitable for use in this species. Significant differences in antibody prevalence were found between age classes of seals s led between 2007 and 2009 at one colony. Pups s led at this site (n=134) were negative for Brucella antibodies by all serologic tests but 17 of 45 (38%) of juveniles were antibody-positive. Antibody prevalence in adult females was significantly higher than in juveniles (P=0.044). Antibody prevalence for adult females between 2003 and 2009 varied significantly over time (P=0.011), and for in iduals s led between 2003 and 2005, the likelihood of pregnancy was greater in in iduals positive for Brucella antibodies (P=0.034). Inflammatory lesions suggestive of infectious agents were found in 14 of 39 aborted Australian fur seal pups, but pathologic changes were not uniformly consistent for Brucella infection. Culture and PCR investigations on fetal tissues were negative for Brucella. Culture and PCR on selected fresh or frozen tissues from 36 juvenile and adult animals were also negative. We suspect that the prevalence of active infection with Brucella in Australian fur seals is low relative to antibody prevalence.
Publisher: Canadian Science Publishing
Date: 12-2006
DOI: 10.1139/Z06-164
Abstract: Foraging by adult male otariids, a demographic component that often interacts with commercial fisheries, are poorly known. To assess movement patterns and habitat use, nine adult male Australian fur seals ( Arctocephalus pusillus doriferus Wood Jones, 1925) from Seal Rocks, in northern Bass Strait, southeastern Australia, were tracked for periods ranging from 66 to 223 d during 1999–2001. Mean ± SD at-sea and on-land durations were 6.9 ± 2.1 d (range 2.3–10.3 d, n = 9 seals) and 2.4 ± 0.9 d (range 0.8–4.1 d), respectively. All seals foraged almost exclusively in continental shelf waters and mostly (65%–97% of time at sea) in water columns that were between 40 and 100 m deep. Six of nine seals tracked for d spent 64%–98% of their time-at-sea foraging at distances km from Seal Rocks, although the maximum distance achieved from the colony was 1208 km. The seals’ foraging ranges overlapped with the ranges of operation of virtually all fin-fish fisheries in southeastern Australia, but fisheries overlap was low in the most frequented foraging area of central-western Bass Strait.
Publisher: Waterbird Society
Date: 06-2007
Publisher: Wiley
Date: 2008
DOI: 10.1002/AQC.857
Publisher: Springer Science and Business Media LLC
Date: 18-04-2020
Publisher: Regional Euro-Asian Biological Invasions Centre Oy (REABIC)
Date: 2016
Publisher: Oxford University Press (OUP)
Date: 30-04-2012
Publisher: PeerJ
Date: 16-10-2018
DOI: 10.7717/PEERJ.5786
Abstract: Global warming is leading to many unprecedented changes in the ocean-climate system. Sea levels are rising at an increasing rate and are lifying the impact of storm surges along coastlines. As variability in the timing and strength of storm surges has been shown to affect pup mortality in the Australian fur seal ( Arctocephalus pusillus doriferus ), there is a need to identify the potential impacts of increased sea level and storm surges on the breeding areas of this important marine predator in Bass Strait, south-eastern Australia. Using high-resolution aerial photography and topographic data, the present study assessed the impacts of future inundation levels on both current and potential breeding habitats at each colony. Inundation from storm surges, based on a predicted rise in sea level, was modeled at each colony from 2012 to 2100. As sea level increases, progressively less severe storm surge conditions will be required to exceed current inundation levels and, thus, have the potential for greater impacts on pup mortality at Australian fur seal colonies. The results of the present study indicate that by 2100, a 1-in-10 year storm will inundate more habitat on average than a present-day 1-in-100 year storm. The study highlights the site-specific nature of storm surge impacts, and in particular the importance of local colony topography and surrounding bathymetry with small, low-lying colonies impacted the most. An increased severity of storm surges will result in either an increase in pup mortality rates associated with storm surges, or the dispersal of in iduals to higher ground and/or new colonies.
Publisher: Springer Science and Business Media LLC
Date: 04-08-2008
Publisher: Inter-Research Science Center
Date: 1997
DOI: 10.3354/MEPS156205
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.MARPOLBUL.2015.10.007
Abstract: Methods of calculating wildlife entanglement rates are not standardised between studies and often ignore the influence of observer effort, confounding comparisons. From 1997-2013 we identified 359 entangled Australian fur seals at Seal Rocks, south-eastern Australia. Most entanglement materials originated from commercial fisheries most frequently entangling pups and juveniles. Using Generalized Additive Mixed Models, which incorporated observer effort and survey frequency, we identified that entanglements were observed more frequently amongst pups from July to October as they approached weaning. Neither the decline in regional fishing intensity nor changing seal population size influenced the incidence of entanglements. Using the models, we estimated that 302 (95% CI=182-510) entangled seals were at Seal Rocks each year, equivalent to 1.0% (CI=0.6-1.7%) of the site population. This study highlights the influence of observer effort and the value of long-term datasets for determining the drivers of marine debris entanglements.
Publisher: Public Library of Science (PLoS)
Date: 18-03-2022
DOI: 10.1371/JOURNAL.PONE.0265610
Abstract: 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.
Publisher: Informa UK Limited
Date: 03-1999
DOI: 10.1071/MU99006
Publisher: Informa UK Limited
Date: 09-2007
DOI: 10.1071/MU07028
Publisher: Springer Science and Business Media LLC
Date: 09-08-2006
Publisher: The Royal Society
Date: 10-2022
DOI: 10.1098/RSOS.211723
Abstract: Marine ecosystems in southeastern Australia are responding rapidly to climate change. We monitored the diet of the Australian fur seal ( Arctocephalus pusillus doriferus ), a key marine predator, over 17 years (1998–2014) to examine temporal changes. Frequency of occurrence (FO) of prey was used as a proxy for ecosystem change. Hard part analysis identified 71 prey taxa, with eight dominant taxa in greater than 70% of s les and predominantly included benthic and small pelagic fish. FO changed over time, e.g. redbait ( Emmelichthys nitidus ) reduced after 2005 when jack mackerel ( Trachurus declivis ) increased, and pilchard ( Sardinops sajax ) increased after 2009. Using generalized additive models, correlations between FO and environmental variables were evident at both the local (e.g. wind, sea surface temperature (SST)) and regional (e.g. El Niño–Southern Oscillation Index (SOI), Southern Annular Mode (SAM)) scales, with redbait and pilchard showing the best model fits (greater than 75% deviance explained). Positive SAM was correlated to FO for both species, and wind and season were important for redbait, while SOI and SST were important for pilchard. Both large-scale and regional processes influenced prey taxa in variable ways. We predict that the erse and adaptable diet of the Australian fur seal will be advantageous in a rapidly changing ecosystem.
Publisher: Aquatic Mammals Journal
Date: 15-05-2018
Publisher: Wiley
Date: 12-04-2017
DOI: 10.1111/MMS.12404
Publisher: Public Library of Science (PLoS)
Date: 05-09-2018
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/ZO11080
Abstract: Australian fur seals (Arctocephalus pusillus doriferus) are the most conspicuous and abundant marine mammal in shelf waters of south-eastern Australia. To successfully rear offspring, the females must encounter sufficient prey on each foraging trip out of a central place for periods up to11 months each year. We investigated foraging trip strategies and habitat use by the females in three winter–spring periods, 2001–03, from four colonies that span the species’ latitudinal range and contribute 80% of pup production. Trip durations of 37 females averaged 6.1 ± 0.5 (s.e.) days, although % of the seal’s time at sea was spent km travel ( days) away. Most females exhibited strong fidelities to in idually preferred hot-spots. Females from colonies adjacent to productive shelf-edge waters generally had shorter trips, had smaller ranges, foraged closer to colonies and exhibited less ersity in trip strategies than did those from colonies more distant from a shelf-edge. From a management perspective, there was minimal overlap ( %) between where females foraged and a system of marine reserves established in 2007, suggesting that habitats visited by lactating Australian fur seals currently receive minimal legislative protection.
Publisher: The Royal Society
Date: 08-2022
Abstract: Past climatic change as a driving force of marine ersification is still largely unclear, particularly for Southern Hemisphere species. Here, we present a case using the brown fur seal, Arctocephalus pusillus, assessing the geographical structure and demographic history using mitochondrial and nuclear data. Results show the two previously defined subspecies (one from Australia and the other from southern Africa) are phylogeographically distinct. Migration analyses based on nuclear data suggest the absence of migrants among the two genetically close assemblages. The demographic history of A. pusillus is characterized by a glacial population expansion (approx. 18 kya) in the southern African lineage, which coincides with time estimates of population expansion of prey species of seals. Approximate Bayesian calculations support an eastward dispersal event during the Last Glacial Maximum when sea levels were lower, followed by a postglacial ergence event, approximately 13 kya. The demographic history of the brown fur seal in the Southern Oceans provides support that recent palaeoclimatic changes could have facilitated expansions in some marine species and that postglacial sea-level rise may have acted as a dispersal barrier for species mostly confined to continental shelves.
Publisher: Springer Science and Business Media LLC
Date: 02-1989
DOI: 10.1007/BF00391143
Publisher: Wiley
Date: 29-08-2013
DOI: 10.1111/ACV.12065
Publisher: CSIRO Publishing
Date: 2000
DOI: 10.1071/AM00087
Abstract: The diet of red foxes (Vulpes vulpes) on Phillip Island, Victoria, was assessed from the frequency of occurrence and volume of food items in stomachs of foxes killed during a 16-year control program (1983 to 1998). Of the 289 stomachs examined, 244 (85%) contained recognisable food items. Based on frequency of occurrence, the most common prey were shorttailed shearwaters (Puffinus tenuirostris, 47%), European rabbits (Oryctolagus cuniculus, 30%), house mice (Mus musculus, 15%), insects (15%), little penguins (Eudyptula minor, 12%), other birds (12%), sheep (Ovis aries 8%) and black rats (Rattus rattus 5%). The seasonal attendance patterns of P. tenuirostris caused substantial variations in the fox diet. When P. tenuirostris were present, between September and April each year, they were the most common food item, and when absent, they were replaced by rabbits. The sex of foxes did not appear to influence diet, but age did. Juvenile (Rubus fructicosus), than did adult foxes.
Publisher: Wiley
Date: 05-1997
Publisher: Wiley
Date: 1993
Publisher: Wiley
Date: 25-12-2013
DOI: 10.1111/MMS.12095
Publisher: Wiley
Date: 27-04-2010
Publisher: Elsevier BV
Date: 03-2014
Publisher: Inter-Research Science Center
Date: 15-08-2019
DOI: 10.3354/MEPS13036
Publisher: Wiley
Date: 2019
DOI: 10.1002/ECS2.2538
Publisher: CSIRO Publishing
Date: 2002
DOI: 10.1071/AM02073
Abstract: In May 1999, four adult male, Australian fur seals (Arctocephalus pusillus doriferus) from the Seal Rocks colony, Victoria, were fitted with satellite transmitters that provided locations for between 2 and 7 months. Foraging trips during winter and early spring averaged 7.4 days (range for all trips 0.9 to 24.6) and between-trip rests lasted 2.8 days (range 0.3 to 5.7). Between-trip rest sites included Seal Rocks, other colonies and other haul-out sites. The seals foraged mostly in western Bass Strait and in water depths 100 m.
Publisher: Wildlife Disease Association
Date: 07-2011
DOI: 10.7589/0090-3558-47.3.555
Abstract: The introduction of pathogens into populations of animals with no previous exposure to them and, therefore, no immunologic protection, can result in epizootics. Predicting the susceptibility of populations to infectious diseases is crucial for their conservation and management. Australian fur seals (Arctocephalus pusillus doriferus) have a relatively small population size, a restricted range, and form dense aggregations. These factors make this species vulnerable to epizootics of infectious diseases that spread by direct animal-to-animal contact. Blood s les were collected from 125 adult female Australian fur seals between 2007 and 2009 and tested for exposure to selected pathogens. The testing protocol was based on pathogens important to marine mammal health or those significant to public and livestock health. No antibodies were detected to morbilliviruses, influenza A viruses, six Leptospira serovars, Mycobacterium tuberculosis-complex species, or Toxoplasma gondii. Overall antibody prevalence to an unidentified Brucella sp. was 57% but varied significantly (P<0.02) between 2007 (74%) and 2008 (53%). The findings indicate Brucella infection may be enzootic in the Australian fur seal population. Further investigations are required to isolate the bacteria and establish if infection results in morbidity and mortality. Australian fur seals remain vulnerable to the threat of introduced disease and should be managed and monitored accordingly.
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/MF09213
Abstract: Australian fur seals (Arctocephalus pusillus doriferus) are conspicuous, top-level predators in coastal waters of south-eastern Australia that were over-harvested during the 1800s and have had a delayed recovery. A previous species-wide estimate of live pups in 2002 recorded a near-doubling of annual pup production and a 5% annual growth rate since the 1980s. To determine if pup production increased after 2002, we estimated live pup numbers in 2007. Pups were recorded at 20 locations: 10 previously known colonies, three newly recognised colonies and seven haul-out sites where pups are occasionally born. Two colonies adjacent to the Victorian coast accounted for 51% of live pups estimated: Seal Rocks (5660 pups, 25.9%) and Lady Julia Percy Island (5574 pups, 25.5%). Although some colonies were up and some were down in pup numbers, the 2007 total of 21 882 ± 187 (s.e.) live pups did not differ significantly from a recalculated estimate of 21 545 ± 184 in 2002, suggesting little change to overall population size. However, the colonisation of three new sites between 2002 and 2007 indicates population recovery has continued.
Publisher: CSIRO Publishing
Date: 1994
DOI: 10.1071/WR9940341
Abstract: In Tasmanian waters Australian fur seals, Arctocephalus pusillus doriferus, breed on five islands in Bass Strait with non-breeding haul-out sites situated in Bass Strait and along the south-eastern and southern Tasmanian coastline. Estimates of pup production were obtained over four breeding seasons between 1989 and 1993 by aerial photography, ground counts and mark-recapture censuses. Pupping commences in late October, with 90% of pups born between 2 and 20 December. Pup mortality is estimated at 15% by early January, when ground censusing was conducted. Pup production of breeding colonies in Tasmanian waters was highest in 1991, with 5130 pups estimated to have been born.
Publisher: CSIRO Publishing
Date: 2002
DOI: 10.1071/WR01056
Abstract: The abundance of Australian fur seal pups was determined at Lady Julia Percy Island in early January 2000 when the average age of pups was 5 weeks. A mark-recapture procedure with repeated recapture sessions was used to estimate abundance of pups in six accessible breeding areas. Pups (n = 1836) were marked by clipping guard hair on the head. Recaptures were conducted visually on 2-4 occasions, when a mean of 41% of sighted pups had been marked. Pup numbers were calculated using a modified Petersen estimate and combined by taking their arithmetic mean. The combined estimate in the accessible breeding areas was 4487 380 pups were counted at two inaccessible sites and 347 dead pups were recorded. Overall, the estimate of abundance for Lady Julia Percy Island was 5214 pups. This exceeds three previous estimates of doubtful veracity for pupping seasons in 1935-36, 1975-76 and 1986-87, and is the greatest number of pups recorded at any Australian fur seal colony. Summation of the most recent estimates of abundance of Australian fur seal pups in all colonies indicates pup production of 16 900 per annum in the 1990s. New Zealand fur seals were also breeding on the island (a mating and four new-born pups were recorded) and two adult male Australian sea lions were observed.
Publisher: Wiley
Date: 14-07-2015
DOI: 10.1111/ECOG.01021
Publisher: CSIRO Publishing
Date: 1992
DOI: 10.1071/WR9920151
Abstract: Observations were made of neck collars of man-made debris on Australian fur seals in Tasmanian waters. These included 47 sightings on six breeding colonies in Bass Strait and 22 on five haul-out sites, one in Bass Strait and four in southern Tasmania. The incidence of entanglement of the population calculated for the southern waters was 1.9 +/- 0.7% (n = 10). Of items identified, polyethylene trawl-net accounted for 40% of neck collars, polypropylene packaging straps 30%, monofilament nets (gill nets) 15% and nylon rope 15%. A variety of colours of polypropylene straps were observed, which indicate a variety of sources of the material. The majority, 66%, of entangled animals were juveniles or subadults a further 16% were non-breeding adult males and 18% were breeding adults. The neck collars were causing obvious physical injury to 73% of the animals observed and in the two worst cases the collars had cut through the oesophagus. Collars made of traw1.net are the greatest cause for concern as they are large, buoyant and originate from a fishery that is increasing in size and produces a lot of debris. The high incidence of neck collars on Australian fur seals indicates that entanglement is a potential threat to the seal population. This effect may not be reflected in the number of pups born until the animals currently being entangled reach breeding age.
Publisher: Frontiers Media SA
Date: 16-02-2022
DOI: 10.3389/FMARS.2022.799102
Abstract: Globally, the bycatch of marine mammals in fisheries represents the greatest source of human-caused mortality that threatens the sustainability of many populations and species. The Australian sea lion ( Neophoca cinerea ) is an endangered species, whose populations off South Australia (SA) have been subject to bycatch in a demersal gillnet fishery targeting sharks since the 1960s. A comprehensive assessment was undertaken of sea lion bycatch mortality that combined independent fishery observer data with species distribution models (underpinned by satellite tracking, abundance data and population modeling) to model the relationship between at-sea foraging effort and bycatch rate. Combined with the distribution of fishing effort, these models enabled the overall level of bycatch mortality to be estimated by age, sex and subpopulation, facilitating population viability analyses that indicated most subpopulations were declining, and subject to unsustainable levels of bycatch mortality. To reduce this mortality, the Australian Fisheries Management Authority implemented an Australian Sea Lion Management Strategy that included an independent observer program (ultimately 100% electronic monitoring of gillnet fishing off SA), permanent spatial gillnet closures around all sea lion breeding sites, bycatch mortality limits that triggered temporal (18 months) spatial closures when zone-specific bycatch trigger limits were reached, and incentives for gillnet fishers to switch to an alternate fishing method (longlines). The Strategy had immediate impacts on the fishery: it resulted in significant reductions in gillnet fishing effort and on the reported bycatch of sea lions. In the next decade, there was an estimated 98% reduction in sea lion bycatch mortality from gillnet interactions and an apparent stabilization of the decline in sea lion pup abundances at some impacted breeding sites. There was an almost complete transition in the fishery from gillnets to longlines, and fishing catches returned to pre-management levels. The successful implementation of management measures to mitigate sea lion bycatch mortality in the gillnet fishery off SA was rapid, science informed, adaptive, comprehensive, and backed by strong compliance and monitoring of the fishery. It provides an important case study which demonstrates how management measures can be effectively applied to mitigate bycatch mortality of marine mammals and other marine protected species.
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/AM01067
Abstract: AUSTRALIAN fur seal (Arctocephalus pusillus doriferus) cows mature at 3 - 6 years of age and, thereafter, are able to give birth to a single pup each year (Warneke and Shaughnessy 1985 Warneke 1995). Pups are born from late October to December and are usually nursed for 8 - 11 months (Warneke and Shaughnessy 1985), however, extended dependency into a second or third year has been recorded (Stirling and Warneke 1971). At Seal Rocks, Victoria, one of nine breeding sites for A. p. doriferus (Warneke 1988 Pemberton and Kirkwood 1994), 11% of young that were observed in association with cows were older than one year (Shaughnessy and Warneke 1987).
Publisher: Springer Science and Business Media LLC
Date: 2004
Publisher: Inter-Research Science Center
Date: 13-10-2008
DOI: 10.3354/MEPS07633
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/WR13196
Abstract: Context Predator-control aims to reduce an impact on prey species, but efficacy of long-term control is rarely assessed and the reductions achieved are rarely quantified. Aims We evaluated the changing efficacy of a 58-year-long c aign against red foxes (Vulpes vulpes) on Phillip Island, a 100-km2 inhabited island connected to the Australian mainland via a bridge. The c aign aimed to eliminate the impact of foxes on ground-nesting birds, particularly little penguins (Eudyptula minor). Methods We monitored the success rate of each fox-control technique employed, the level of effort invested if available, demographics of killed foxes, the numbers of penguins killed by foxes and penguin population size. Key results The c aign began as a bounty system that ran for 30 years and was ineffective. It transitioned into a coordinated, although localised, control program from 1980 to 2005 that invested considerable effort, but relied on subjective assessments of success. Early during the control period, baiting was abandoned for less effective methods that were thought to pose fewer risks, were more enjoyable and produced carcasses, a tangible result. Control was aided by a high level of public awareness, by restricted fox immigration, and by a clear, achievable and measurable target, namely, to prevent little penguin predation by foxes. Carcasses did prove valuable for research, revealing the genetic structure and shifts in fox demographics. The failure of the program was evident after scientific evaluation of fox population size and ongoing fox impacts. In 2006, the c aign evolved into an eradication attempt, adopting regular island-wide baiting, and since then, has achieved effective knock-down of foxes and negligible predation on penguins. Conclusions Effective predator control was achieved only after employing a dedicated team and implementing broad-scale baiting. Abandoning widespread baiting potentially delayed effective control for 25 years. Furthermore, both predator and prey populations should be monitored concurrently because the relationship between predator abundance and impact on prey species is not necessarily density dependent. Implications Critical to adopting the best management strategy is evaluating the efficacy of different methods independently of personal and public biases and having personnel dedicated solely to the task.
Publisher: Wiley
Date: 30-09-2014
DOI: 10.1111/MMS.12171
Publisher: Wiley
Date: 17-12-2013
DOI: 10.1111/MMS.12094
Publisher: Wiley
Date: 04-2005
No related grants have been discovered for Roger Kirkwood.