ORCID Profile
0000-0002-0233-5782
Current Organisations
University of California Santa Cruz
,
Uniiversity of California
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Marine And Estuarine Ecology (Incl. Marine Ichthyology) | Sociobiology And Behavioural Ecology | Ecology | Wildlife And Habitat Management
Other | Living resources (incl. impacts of fishing on non-target species) | Biological sciences |
Publisher: Public Library of Science (PLoS)
Date: 07-2015
Publisher: Elsevier BV
Date: 09-2016
Publisher: Wiley
Date: 20-06-2016
Publisher: American Association for the Advancement of Science (AAAS)
Date: 05-02-2021
Abstract: Sound travels faster and farther in water than in air. Over evolutionary time, many marine organisms have come to rely on sound production, transmission, and reception for key aspects of their lives. These important behaviors are threatened by an increasing cacophony in the marine environment as human-produced sounds have become louder and more prevalent. Duarte et al. review the importance of biologically produced sounds and the ways in which anthropogenically produced sounds are affecting the marine soundscape. Science , this issue p. eaba4658
Publisher: Springer Science and Business Media LLC
Date: 08-03-2017
DOI: 10.1038/S41598-017-00165-0
Abstract: The growing number of large databases of animal tracking provides an opportunity for analyses of movement patterns at the scales of populations and even species. We used analytical approaches, developed to cope with “big data”, that require no ‘ a priori’ assumptions about the behaviour of the target agents, to analyse a pooled tracking dataset of 272 elephant seals ( Mirounga leonina ) in the Southern Ocean, that was comprised of ,000 location estimates collected over more than a decade. Our analyses showed that the displacements of these seals were described by a truncated power law distribution across several spatial and temporal scales, with a clear signature of directed movement. This pattern was evident when analysing the aggregated tracks despite a wide ersity of in idual trajectories. We also identified marine provinces that described the migratory and foraging habitats of these seals. Our analysis provides evidence for the presence of intrinsic drivers of movement, such as memory, that cannot be detected using common models of movement behaviour. These results highlight the potential for “big data” techniques to provide new insights into movement behaviour when applied to large datasets of animal tracking.
Publisher: Wiley
Date: 15-01-2023
DOI: 10.1111/GCB.16559
Abstract: The krill surplus hypothesis of unlimited prey resources available for Antarctic predators due to commercial whaling in the 20th century has remained largely untested since the 1970s. Rapid warming of the Western Antarctic Peninsula (WAP) over the past 50 years has resulted in decreased seasonal ice cover and a reduction of krill. The latter is being exacerbated by a commercial krill fishery in the region. Despite this, humpback whale populations have increased but may be at a threshold for growth based on these human‐induced changes. Understanding how climate‐mediated variation in prey availability influences humpback whale population dynamics is critical for focused management and conservation actions. Using an 8‐year dataset (2013–2020), we show that inter‐annual humpback whale pregnancy rates, as determined from skin‐blubber biopsy s les ( n = 616), are positively correlated with krill availability and fluctuations in ice cover in the previous year. Pregnancy rates showed significant inter‐annual variability, between 29% and 86%. Our results indicate that krill availability is in fact limiting and affecting reproductive rates, in contrast to the krill surplus hypothesis. This suggests that this population of humpback whales may be at a threshold for population growth due to prey limitations. As a result, continued warming and increased fishing along the WAP, which continue to reduce krill stocks, will likely impact this humpback whale population and other krill predators in the region. Humpback whales are sentinel species of ecosystem health, and changes in pregnancy rates can provide quantifiable signals of the impact of environmental change at the population level. Our findings must be considered paramount in developing new and more restrictive conservation and management plans for the Antarctic marine ecosystem and minimizing the negative impacts of human activities in the region.
Publisher: Wiley
Date: 05-2016
DOI: 10.1002/ECS2.1213
Publisher: Springer Science and Business Media LLC
Date: 23-09-2012
DOI: 10.1038/NCLIMATE1686
Publisher: Elsevier BV
Date: 2013
Publisher: American Association for the Advancement of Science (AAAS)
Date: 03-12-2010
Publisher: Elsevier BV
Date: 05-0008
Publisher: The Royal Society
Date: 07-08-2013
Abstract: Body size affects nearly all aspects of organismal biology, so it is important to understand the constraints and dynamics of body size evolution. Despite empirical work on the macroevolution and macroecology of minimum and maximum size, there is little general quantitative theory on rates and limits of body size evolution. We present a general theory that integrates in idual productivity, the lifestyle component of the slow–fast life-history continuum, and the allometric scaling of generation time to predict a clade's evolutionary rate and asymptotic maximum body size, and the shape of macroevolutionary trajectories during ersifying phases of size evolution. We evaluate this theory using data on the evolution of clade maximum body sizes in mammals during the Cenozoic. As predicted, clade evolutionary rates and asymptotic maximum sizes are larger in more productive clades (e.g. baleen whales), which represent the fast end of the slow–fast lifestyle continuum, and smaller in less productive clades (e.g. primates). The allometric scaling exponent for generation time fundamentally alters the shape of evolutionary trajectories, so allometric effects should be accounted for in models of phenotypic evolution and interpretations of macroevolutionary body size patterns. This work highlights the intimate interplay between the macroecological and macroevolutionary dynamics underlying the generation and maintenance of morphological ersity.
Publisher: Wiley
Date: 03-11-2012
Publisher: Proceedings of the National Academy of Sciences
Date: 30-01-2012
Abstract: How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous–Paleogene (K–Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes.
Publisher: Elsevier BV
Date: 2004
DOI: 10.1016/J.BBRC.2003.12.012
Abstract: Marine mammals have a spectacular suite of respiratory adaptations to deal with the extreme pressures associated with deep ing. In particular, maintaining a functional pulmonary surfactant system at depth is critical for marine mammals to ensure that inspiration is possible upon re-emergence. Pulmonary surfactant is secreted from alveolar type II (ATII) cells and is crucial for normal lung function. It is not known whether ATII cells have the ability to continue to secrete pulmonary surfactant under pressure, or how secretion is maintained and controlled. We show here that surfactant secretion in California sea lions (Zalophus californianus) was increased after high pressures (25 and 50 atm) of short duration (30 min), but was unaffected by high pressures of long duration (2 h). This is in contrast to a similar sized terrestrial mammal (sheep), where surfactant secretion was increased after high pressures of both long and short duration. Z. californianus and terrestrial mammals also show similar responses to stimulatory hormones and autonomic neurotransmitters. It therefore seems that an increase in the quantity of surfactant in seal lungs after ing is most likely caused by mechanostimulation induced by pressure and volume changes, and that seals are adapted to maintain constant levels of surfactant under long periods of high pressure.
Publisher: Wiley
Date: 19-07-2013
Publisher: Wiley
Date: 31-07-2013
DOI: 10.1111/DDI.12118
Publisher: Oxford University Press (OUP)
Date: 14-09-2012
Publisher: Elsevier BV
Date: 04-2013
Publisher: Inter-Research Science Center
Date: 22-04-2015
DOI: 10.3354/MEPS11200
Publisher: Frontiers Media SA
Date: 26-09-2017
Publisher: Inter-Research Science Center
Date: 29-08-2008
DOI: 10.3354/MEPS07507
Publisher: Springer Science and Business Media LLC
Date: 22-06-2011
DOI: 10.1038/NATURE10082
Abstract: Pelagic marine predators face unprecedented challenges and uncertain futures. Overexploitation and climate variability impact the abundance and distribution of top predators in ocean ecosystems. Improved understanding of ecological patterns, evolutionary constraints and ecosystem function is critical for preventing extinctions, loss of bio ersity and disruption of ecosystem services. Recent advances in electronic tagging techniques have provided the capacity to observe the movements and long-distance migrations of animals in relation to ocean processes across a range of ecological scales. Tagging of Pacific Predators, a field programme of the Census of Marine Life, deployed 4,306 tags on 23 species in the North Pacific Ocean, resulting in a tracking data set of unprecedented scale and species ersity that covers 265,386 tracking days from 2000 to 2009. Here we report migration pathways, link ocean features to multispecies hotspots and illustrate niche partitioning within and among congener guilds. Our results indicate that the California Current large marine ecosystem and the North Pacific transition zone attract and retain a erse assemblage of marine vertebrates. Within the California Current large marine ecosystem, several predator guilds seasonally undertake north-south migrations that may be driven by oceanic processes, species-specific thermal tolerances and shifts in prey distributions. We identify critical habitats across multinational boundaries and show that top predators exploit their environment in predictable ways, providing the foundation for spatial management of large marine ecosystems.
Publisher: Wiley
Date: 13-03-2021
DOI: 10.1002/ECE3.7337
Publisher: Elsevier BV
Date: 05-2012
Publisher: American Association for the Advancement of Science (AAAS)
Date: 04-05-2018
Abstract: Dynamic management approaches protect endangered bycatch species but with much greater efficiency than existing static closures.
Publisher: Inter-Research Science Center
Date: 27-02-2017
DOI: 10.3354/MEPS12024
Publisher: Elsevier BV
Date: 06-2012
Publisher: Elsevier BV
Date: 08-2015
Publisher: American Geophysical Union (AGU)
Date: 11-2010
DOI: 10.1029/2010GL044921
Publisher: Public Library of Science (PLoS)
Date: 18-02-2015
Publisher: Public Library of Science (PLoS)
Date: 15-01-2010
Publisher: American Geophysical Union (AGU)
Date: 03-12-2013
DOI: 10.1002/2013GL058304
Abstract: Over the last decade, several hundred seals have been equipped with conductivity‐temperature‐depth sensors in the Southern Ocean for both biological and physical oceanographic studies. A calibrated collection of seal‐derived hydrographic data is now available, consisting of more than 165,000 profiles. The value of these hydrographic data within the existing Southern Ocean observing system is demonstrated herein by conducting two state estimation experiments, differing only in the use or not of seal data to constrain the system. Including seal‐derived data substantially modifies the estimated surface mixed‐layer properties and circulation patterns within and south of the Antarctic Circumpolar Current. Agreement with independent satellite observations of sea ice concentration is improved, especially along the East Antarctic shelf. Instrumented animals efficiently reduce a critical observational gap, and their contribution to monitoring polar climate variability will continue to grow as data accuracy and spatial coverage increase.
Publisher: American Geophysical Union (AGU)
Date: 2012
DOI: 10.1029/2011JC007301
Publisher: The Royal Society
Date: 07-06-2014
Abstract: There is accumulating evidence that macroevolutionary patterns of mammal evolution during the Cenozoic follow similar trajectories on different continents. This would suggest that such patterns are strongly determined by global abiotic factors, such as climate, or by basic eco-evolutionary processes such as filling of niches by specialization. The similarity of pattern would be expected to extend to the history of in idual clades. Here, we investigate the temporal distribution of maximum size observed within in idual orders globally and on separate continents. While the maximum size of in idual orders of large land mammals show differences and comprise several families, the times at which orders reach their maximum size over time show strong congruence, peaking in the Middle Eocene, the Oligocene and the Plio-Pleistocene. The Eocene peak occurs when global temperature and land mammal ersity are high and is best explained as a result of niche expansion rather than abiotic forcing. Since the Eocene, there is a significant correlation between maximum size frequency and global temperature proxy. The Oligocene peak is not statistically significant and may in part be due to s ling issues. The peak in the Plio-Pleistocene occurs when global temperature and land mammal ersity are low, it is statistically the most robust one and it is best explained by global cooling. We conclude that the macroevolutionary patterns observed are a result of the interplay between eco-evolutionary processes and abiotic forcing.
Publisher: The Company of Biologists
Date: 2016
DOI: 10.1242/JEB.138677
Abstract: Our understanding of how air-breathing marine predators cope with environmental variability is limited by our inadequate knowledge of their ecological and physiological parameters. Due to their wide distribution along both coasts of the sub-continent, South American sea lions (Otaria byronia) provide a valuable opportunity to study the behavioral and physiological plasticity of a marine predator in different environments. We measured the oxygen stores and ing behavior of South American sea lions throughout most of its range, allowing us to demonstrate that ing ability and behavior vary across its range. We found no significant differences in mass-specific blood volumes of sea lions among field sites and a negative relationship between mass-specific oxygen storage and size, which suggests that exposure to different habitats and geographical locations better explains oxygen storage capacities and ing capability in South American sea lions than body size alone. The largest animals in our study (in iduals from Uruguay) were the most shallow and short duration ers, and had the lowest mass-specific total body oxygen stores, while the deepest and longest duration ers (in iduals from Southern Chile) had significantly larger mass-specific oxygen stores, despite being much smaller animals. Our study suggests that the physiology of air-breathing ing predators is not fixed, but that it can be adjusted, to a certain extent, depending on the ecological setting and or habitat. These adjustments can be thought of as a “training effect” as the animal continues to push its physiological capacity through greater hypoxic exposure, its breath holding capacity increases.
Publisher: Elsevier BV
Date: 02-2008
Publisher: Elsevier BV
Date: 06-2016
DOI: 10.1016/J.TREE.2016.02.015
Abstract: It is a golden age for animal movement studies and so an opportune time to assess priorities for future work. We assembled 40 experts to identify key questions in this field, focussing on marine megafauna, which include a broad range of birds, mammals, reptiles, and fish. Research on these taxa has both underpinned many of the recent technical developments and led to fundamental discoveries in the field. We show that the questions have broad applicability to other taxa, including terrestrial animals, flying insects, and swimming invertebrates, and, as such, this exercise provides a useful roadmap for targeted deployments and data syntheses that should advance the field of movement ecology.
Publisher: Public Library of Science (PLoS)
Date: 04-06-2010
Publisher: Proceedings of the National Academy of Sciences
Date: 19-08-2008
Abstract: Polar regions are particularly sensitive to climate change, with the potential for significant feedbacks between ocean circulation, sea ice, and the ocean carbon cycle. However, the difficulty in obtaining in situ data means that our ability to detect and interpret change is very limited, especially in the Southern Ocean, where the ocean beneath the sea ice remains almost entirely unobserved and the rate of sea-ice formation is poorly known. Here, we show that southern elephant seals ( Mirounga leonina ) equipped with oceanographic sensors can measure ocean structure and water mass changes in regions and seasons rarely observed with traditional oceanographic platforms. In particular, seals provided a 30-fold increase in hydrographic profiles from the sea-ice zone, allowing the major fronts to be mapped south of 60°S and sea-ice formation rates to be inferred from changes in upper ocean salinity. Sea-ice production rates peaked in early winter (April–May) during the rapid northward expansion of the pack ice and declined by a factor of 2 to 3 between May and August, in agreement with a three-dimensional coupled ocean–sea-ice model. By measuring the high-latitude ocean during winter, elephant seals fill a “blind spot” in our s ling coverage, enabling the establishment of a truly global ocean-observing system.
Publisher: Springer Science and Business Media LLC
Date: 03-05-2013
Publisher: The Royal Society
Date: 23-03-2011
Abstract: Fisheries bycatch is a recognized threat to marine megafauna. Addressing bycatch of pelagic species however is challenging owing to the dynamic nature of marine environments and vagility of these organisms. In order to assess the potential for species to overlap with fisheries, we propose applying dynamic habitat models to determine relative probabilities of species occurrence for specific oceanographic conditions. We demonstrate this approach by modelling habitats for Laysan ( Phoebastria immutabilis ) and black-footed albatrosses ( Phoebastria nigripes ) using telemetry data and relating their occurrence probabilities to observations of Hawaii-based longline fisheries in 1997–2000. We found that modelled habitat preference probabilities of black-footed albatrosses were high within some areas of the fishing range of the Hawaiian fleet and such preferences were important in explaining bycatch occurrence. Conversely, modelled habitats of Laysan albatrosses overlapped little with Hawaii-based longline fisheries and did little to explain the bycatch of this species. Estimated patterns of albatross habitat overlap with the Hawaiian fleet corresponded to bycatch observations: black-footed albatrosses were more frequently caught in this fishery despite being 10 times less abundant than Laysan albatrosses. This case study demonstrates that dynamic habitat models based on telemetry data may help to project interactions with pelagic animals relative to environmental features and that such an approach can serve as a tool to guide conservation and management decisions.
Publisher: Elsevier BV
Date: 09-2012
Location: United States of America
Start Date: 01-2006
End Date: 12-2009
Amount: $219,000.00
Funder: Australian Research Council
View Funded Activity