Roger Kirkwood

Roger Kirkwood
South Australian Research and Development Institute | SARDI · Aquatic Sciences Research Division

PhD

About

129
Publications
39,189
Reads
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3,157
Citations
Citations since 2017
29 Research Items
1469 Citations
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2017201820192020202120222023050100150200250300
2017201820192020202120222023050100150200250300
Additional affiliations
September 1997 - March 2013
Phillip Island Nature Parks
Position
  • Researcher
Description
  • Seal, seabird, terrestrial mammal research

Publications

Publications (129)
Article
Full-text available
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 ide...
Article
Past climatic change as a driving force of marine diversification 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...
Technical Report
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Report reviews threats to Indo-Pacific bottlenose dolphins (Tursiops aduncus) in the Adelaide Dolphin Sanctuary, located in the Port River and Barker Inlet, South Australia
Article
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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,...
Article
Full-text available
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 ta...
Article
Full-text available
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 (Austr...
Chapter
The Australian fur seal (Arctocephalus pusillus doriferus) resulted from an emigration by South African fur seals (A. p. pusillus) across the Indian Ocean 18,000 to 12,000 years ago. The sub-species look and behave similarly. The Australian fur seal has a smaller range, smaller population density and smaller total population probably because waters...
Article
Full-text available
Southern Ocean ecosystems are under pressure from resource exploitation and climate change1,2. Mitigation requires the identification and protection of Areas of Ecological Significance (AESs), which have so far not been determined at the ocean-basin scale. Here, using assemblage-level tracking of marine predators, we identify AESs for this globally...
Article
Full-text available
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 Biodiversity Informatics, and endorsed by the Commission for the Conservation of Antarctic Marine Living Resources. RAATD consolidated tracking data for mul...
Article
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 Biodiversity Informatics, and endorsed by the Commission for the Conservation of Antarctic Marine Living Resources. RAATD consolidated tracking data for mul...
Article
Full-text available
Plain Language Summary Polar ecosystems are threatened by future loss of sea ice. The availability of satellite sea ice products has facilitated a better assessment of the impact of sea ice on polar species. Yet most studies have focused on coarse spatial scale sea ice products hampering an understanding of the mechanisms by which sea ice affects s...
Article
Sexual segregation in foraging is often attributed to constraints arising from sexual size dimorphism, such as differing physiological abilities and energy requirements, or to reproductive commitments including nutritional requirements and behavioural limitations such as parental care. In species with sexual size dimorphism and a polygynous mating...
Article
Full-text available
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 have regained their prominent position as top predator in marine ecosystems. Also, the harbor seal population in the international Wadden Sea grew at an expon...
Article
Full-text available
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 di...
Article
Full-text available
Global warming is leading to many unprecedented changes in the ocean-climate system. Sea levels are rising at an increasing rate and are amplifying 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 doriferu...
Article
Full-text available
Effective ecosystem-based management requires estimates of abundance and population trends of species of interest. Trend analyses are often limited due to sparse or short-term abundance estimates for populations that can be logistically difficult to monitor over time. Therefore it is critical to assess regularly the quality of the metrics in long-t...
Article
Full-text available
This erratum concerns Figure 9 of the original article in which the line delimiting two effect types ("Permanent hearing loss increasingly likely" and "Permanent hearing loss very likely") was misplaced. This error, which has now been corrected, affects neither the main text nor the conclusion of the study. The authors apologize for the error.
Article
Full-text available
Terrestrial and marine wildlife populations have been severely reduced by hunting, fishing and habitat destruction, especially in the last centuries. Although management regulations have led to the recovery of some populations, the underlying processes are not always well understood. This study uses a 40-year time series of counts of harbour seals...
Data
Overview of number of surveys per year. M = moult, P = pupping season. (DOCX)
Data
Annual maximum counts for total numbers (during moult) and pups. Left column indicates the periods. (DOCX)
Article
Full-text available
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...
Experiment Findings
Full-text available
Historic records and acoustic survey results - unpublished report
Article
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Surveys of gray seals (Halichoerus grypus) during the molt period, when they are abundant on land, can be used to monitor changes in population size, but accurate interpretation of results requires an understanding of the molt process and how it may vary between years. This study investigates variability in onset (start date) and duration of visibl...
Article
Full-text available
Anthropogenic sound in the marine environment can have negative consequences for marine fauna. Since most sound sources are intermittent or continuous, estimating how many individuals are exposed over time remains challenging, as this depends on the animals’ mobility. Here we explored how animal movement influences how many, and how often, animals...
Article
Full-text available
Studying offshore natural and artificial hard substrates in the southern North Sea (51ºN–57ºN/1ºW–9ºE), the invasive introduced Japanese skeleton shrimp Caprella mutica Schurin, 1935 was found to co-exist with the native Caprella linearis (Linnaeus, 1767) only on near-shore locations that had an intertidal zone (e.g., wind farm foundations). In con...
Conference Paper
Full-text available
New island development is not very often observed in the Dutch Wadden Sea. Richel had long been an unvegetated sand bar, located on the Wadden Sea side of Vlieland. The past ten years, vegetation has established and an embryonic dune field has developed. The dune field is dominated by Sand Couch (Elytrigia juncea), and was in 2014 home to at least...
Article
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Large amounts of legacy unexploded ordnance (UXO) are still present in the North Sea. UXO are frequently accidentally encountered by fishermen and dredging vessels. Out of concern for human safety and to avoid damage to equipment and infrastructure from uncontrolled explosions, most reported UXO found in the Dutch Continental Shelf (DCS) are detona...
Technical Report
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Atlantic grey seals (Halichoerus grypus grypus) started recolonising Dutch coastal haul-outs in the 1950s, after >2000 years of rarity in the Dutch coastal zone which was caused mainly by human hunting. The first pup-birth was recorded in 1985 at the Wadden Sea sandbank of Engelschhoek. Sandbanks in the Wadden Sea form and recede in periods of de...
Presentation
Abstract: How to manage the recovery of large vertebrates into areas with established human populations is an increasingly vexing issue for conservation practice. This has been particularly difficult for wide-ranging marine fauna due to limitations in quantifying habitat use, life-history requirements and population growth. We quantify spatial and...
Presentation
Full-text available
How to manage the recovery of previously exploited large vertebrates with increasing range-incursions into areas with established human populations is an increasingly vexing issue for conservation practice. This has been particularly difficult for wide-ranging marine fauna due to limitations in quantifying habitat use, life-history requirements and...
Technical Report
Full-text available
Two species of seals live in Dutch waters: the grey seal (Halichoerus grypus) and the harbour seal (Phoca vitulina). Although hauling out on near-shore tidal sandbanks, both species forage predominantly in the North Sea. Anthropogenic activities within the North Sea have the potential to overlap with the movement and habitat use of the seals, and a...
Technical Report
Full-text available
Two seal species live in Dutch waters: the harbour seal (Phoca vitulina) and the grey seal (Halichoerus grypus). They occupy land-based sites (haul-outs) in both the Wadden Sea and the Delta region, and move between these regions along the North Sea coastal zone. Human activities, such as construction of a wind farm in this zone, may influence move...
Technical Report
Full-text available
In accordance with the monitoring and evaluation plan (MEP) for the ‘Gemini Offshore Wind Farm’ the ecological monitoring of harbour porpoises was carried out by IMARES and IBL Umweltplanung, concerning the distribution and numbers of harbour porpoises in and around the wind farm prior to construction (T-0). For this purpose aerial surveys as well...
Technical Report
Full-text available
Monitoring harbour seal responses to construction of power stations and harbour development at Eems River mouth.
Article
Full-text available
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 campaign against red foxes (Vulpes vulpes) on Phillip Island, a 100-km2 inhabited island connected to the Australian m...
Article
Full-text available
Animals that establish new sites near the edge of the species' range may be vulnerable to disturbance as they are low in numbers and are not tied to the sites. Pinniped distributions world-wide are changing as many species are recolonizing areas of their former ranges and establishing new colonies. Little research is available on the impact that ve...
Conference Paper
Full-text available
Predator control aims to reduce impacts on prey species, but efficacy of long-term control is rarely assessed and the reductions achieved rarely quantified. We evaluate the changing efficacy of a 58-year long campaign against red foxes (Vulpes vulpes) on Phillip Island, a 100-km2 inhabited island connected to the Australian mainland via a bridge. T...
Conference Paper
Repeated pup censuses for the Australian fur seal (Arctocephalus pusillus doriferus) have been performed across the species’ range every five years since 2002 to monitor population trends. Live pup numbers were estimated at 20 pupping sites using one of the following methods: capture-mark-resight, direct count, or count from aerial photograph. From...
Article
Full-text available
Satellite telemetry data are a key source of animal distribution information for marine ecosystem management and conservation activities. We used two decades of telemetry data from the East Antarctic sector of the Southern Ocean. Habitat utilization models for the spring/summer period were developed for six highly abundant, wide-ranging meso- and t...
Article
Full-text available
Imperfect detection methods make it difficult to tell whether an invasive species has been successfully eradicated. However, management cannot continue indefinitely when individuals are no longer detected – at some point, efforts must be reduced or ceased entirely. The risks of mistakenly inferring that an eradication attempt has been successful ca...
Article
Full-text available
Wildlife tourism (including pinniped tourism) offers people the opportunity to see wildlife in their natural environment. It can provide positive outcomes for the animals, through improved resources for conservation, or negative outcomes, such as inducing the animals to move away. This study assessed the impacts and sustainability of a novel but gr...
Conference Paper
Full-text available
Worldwide, many seal populations have increased dramatically in recent decades. The increases may be related to a range of local influences, however, the global distribution of such increases suggests non-local factors are involved. One seal that has exhibited such an increase is the Australian fur seal, Arctocephalus pusillus doriferus. This South...
Technical Report
Full-text available
Growth in numbers has seen the Netherlands become a strong-hold for grey seals in continental Europe. This report has the following subjects (questions posed by the Dutch Ministry): “Is a favourable status of the habitat quality of the grey seal in the Netherlands dependant on the presence of undisturbed, permanently dry breeding sites, or do the c...
Technical Report
Full-text available
In the Netherlands, the greatest numbers of grey and harbour seals are observed hauling out in the Wadden Sea but both species also haul out in the Delta region. Previous studies suggest there could be considerable movement of seals along the Dutch North Sea coastal zone between the two regions. Next to providing feeding opportunities for the seals...
Technical Report
Full-text available
This report presents data on use by seals tracked from the Netherlands of a zone of the North Sea off the east coast of the UK, the East Anglia Zone, where it is proposed to develop offshore windfarms. For this report, three areas of interest are distinguished within the East Anglia Zone: East Anglia THREE Offshore Windfarm (East Anglia THREE); Eas...
Article
Full-text available
Observing how pinnipeds respond to variations in climatic and oceanographic conditions informs marine managers on factors that could limit their range, foraging ability and breeding success. Here, we examine how Australian fur seals (Arctocephalus pusillus doriferus) at Seal Rocks, Victoria, Australia, responded to normal climatic conditions from A...
Presentation
While males and females may co-exist in the same habitat, sexual segregation in foraging behaviour is common among vertebrates. It is usually attributed to physiological differences, trophic niche divergence, size dimorphism, or reproductive role specialisation, and is ubiquitous in adult otariids. We investigated whether sexual segregation in fora...
Book
Full-text available
Fur seals and sea lions are charismatic, large carnivores that engage us with both their skill and playful antics. Although all species in Australian waters were harvested to near extinction 200 years ago, fur seals are recovering and are now common in near-shore waters across southern Australia. Sea lions, however, are endangered. Their population...
Conference Paper
Black-browed albatrosses are a common victim of incidental mortality in commercial fishing operations. Chile holds globally important populations of black-browed and grey-headed albatrosses with the bulk (~85%) of black-browed albatrosses breeding at two of six known sites, the Diego Ramirez and Ildefonso archipelagos. Virtually the entire populati...
Conference Paper
Full-text available
Eradication of introduced predators from ‘predator-naïve’ ecosystems can have profound benefits. Accomplishing eradications is difficult, as is confidently identifying when they are achieved. False or delayed declarations carry significant risks. Declaring too early allows predators to re-establish, and declaring too late can be unnecessarily costl...