11 research outputs found

    Diving behavior and fine-scale kinematics of free-ranging Risso’s dolphins foraging in shallow and deep-water habitats

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    Funding: SOCAL-BRS project, Chief of Naval Operations Environmental Readiness Division, the US Navy's Living Marine Resources Program, and the Office of Naval Research Marine Mammal Program; ONR grant N00014-15-1-255 and the MASTS pooling initiative (Marine Alliance for Science and Technology for Scotland supported by the Scottish Funding Council, grant reference HR09011, and contributing institutions) (PLT).Air-breathing marine predators must balance the conflicting demands of oxygen conservation during breath-hold and the cost of diving and locomotion to capture prey. However, it remains poorly understood how predators modulate foraging performance when feeding at different depths and in response to changes in prey distribution and type. Here, we used high-resolution multi-sensor tags attached to Risso’s dolphins (Grampus griseus) and concurrent prey surveys to quantify their foraging performance over a range of depths and prey types. Dolphins (N=33) foraged in shallow and deep habitats [seabed depths less or more than 560m, respectively] and within the deep habitat, in vertically stratified prey features occurring at several aggregation levels. Generalized linear mixed-effects models indicated that dive kinematics were driven by foraging depth rather than habitat. Bottom-phase duration and number of buzzes (attempts to capture prey) per dive increased with depth. In deep dives, dolphins were gliding for >50% of descent and adopted higher pitch angles both during descent and ascents, which was likely to reduce energetic cost of longer transits. This lower cost of transit was counteracted by the record of highest vertical swim speeds, rolling maneuvers and stroke rates at depth, together with a 4-fold increase in the inter-buzz interval, suggesting higher costs of pursuing and handling prey compared to shallow-water feeding. In spite of the increased capture effort at depth, dolphins managed to keep their estimated overall metabolic rate comparable across dive types. This indicates that adjustments in swimming modes may enable energy balance in deeper dives. If we think of the surface as a central place where divers return to breathe, our data match predictions that central place foragers should increase the number and likely quality of prey items at greater distances. These dolphins forage efficiently from near-shore benthic communities to depth-stratified scattering layers, enabling them to maximize their fitness.Publisher PDFPeer reviewe

    Diving Behavior and Fine-Scale Kinematics of Free-Ranging Risso's Dolphins Foraging in Shallow and Deep-Water Habitats

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    Air-breathing marine predators must balance the conflicting demands of oxygen conservation during breath-hold and the cost of diving and locomotion to capture prey. However, it remains poorly understood how predators modulate foraging performance when feeding at different depths and in response to changes in prey distribution and type. Here, we used high-resolution multi-sensor tags attached to Risso's dolphins (Grampus griseus) and concurrent prey surveys to quantify their foraging performance over a range of depths and prey types. Dolphins (N = 33) foraged in shallow and deep habitats [seabed depths less or more than 560 m, respectively] and within the deep habitat, in vertically stratified prey features occurring at several aggregation levels. Generalized linear mixed-effects models indicated that dive kinematics were driven by foraging depth rather than habitat. Bottom-phase duration and number of buzzes (attempts to capture prey) per dive increased with depth. In deep dives, dolphins were gliding for >50% of descent and adopted higher pitch angles both during descent and ascents, which was likely to reduce energetic cost of longer transits. This lower cost of transit was counteracted by the record of highest vertical swim speeds, rolling maneuvers and stroke rates at depth, together with a 4-fold increase in the inter-buzz interval (IBI), suggesting higher costs of pursuing, and handling prey compared to shallow-water feeding. In spite of the increased capture effort at depth, dolphins managed to keep their estimated overall metabolic rate comparable across dive types. This indicates that adjustments in swimming modes may enable energy balance in deeper dives. If we think of the surface as a central place where divers return to breathe, our data match predictions that central place foragers should increase the number and likely quality of prey items at greater distances. These dolphins forage efficiently from near-shore benthic communities to depth-stratified scattering layers, enabling them to maximize their fitness

    A View from the Past Into our Collective Future: The Oncofertility Consortium Vision Statement

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    Today, male and female adult and pediatric cancer patients, individuals transitioning between gender identities, and other individuals facing health extending but fertility limiting treatments can look forward to a fertile future. This is, in part, due to the work of members associated with the Oncofertility Consortium. The Oncofertility Consortium is an international, interdisciplinary initiative originally designed to explore the urgent unmet need associated with the reproductive future of cancer survivors. As the strategies for fertility management were invented, developed or applied, the individuals for who the program offered hope, similarly expanded. As a community of practice, Consortium participants share information in an open and rapid manner to addresses the complex health care and quality-of-life issues of cancer, transgender and other patients. To ensure that the organization remains contemporary to the needs of the community, the field designed a fully inclusive mechanism for strategic planning and here present the findings of this process. This interprofessional network of medical specialists, scientists, and scholars in the law, medical ethics, religious studies and other disciplines associated with human interventions, explore the relationships between health, disease, survivorship, treatment, gender and reproductive longevity. The goals are to continually integrate the best science in the service of the needs of patients and build a community of care that is ready for the challenges of the field in the future

    Smokers’ Response to Corrective Statements and Implications for Media Campaigns

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    In 1999, the Federal Government sued the tobacco companies in an attempt to recover expenses used to treat diseases caused by smoking. The 2006 verdict required the dissemination of corrective statements intended to inform the public of the dangers of smoking. This study analyzes smokers\u27 perceptions of these statements. Statements were tested from November 5 to December 5, 2007. Results indicate: (1) messages created by public health intervenors and tobacco companies tended to have higher mean scores than those created by the DOJ, (2) statements on nicotine being addictive had significantly higher mean scores than the other two sets tested, (3) that all statements were rated higher in terms of believability than in terms of other factors, and (4) light smokers rated statements higher in terms of motivating and likelihood to quit than did medium or heavy smokers. These results will be used to refine the development of corrective statements

    Humpback whale song occurrence reflects ecosystem variability in feeding and migratory habitat of the northeast Pacific

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    Most physical oceanographic data and some biological data used in this study are available through servers supported by federal and state agencies, as specified in the Methods section. Glider data are available from UCSD: https://spraydata.ucsd.edu/ projects/CUGN/. All other data presented have been deposited in a repository and are available at: https://doi.org/10.6084/m9.figshare.c.4584026.v1.The article of record as published may be found at https://doi.org/10.1371/journal.pone.0222456This study examines the occurrence of humpback whale (Megaptera novaeangliae) song in the northeast Pacific from three years of continuous recordings off central California (36.713˚N, 122.186˚W). Song is prevalent in this feeding and migratory habitat, spanning nine months of the year (September–May), peaking in winter (November–January), and reaching a maximum of 86% temporal coverage (during November 2017). From the rise of song in fall through the end of peak occurrence in winter, song length increases significantly from month to month. The seasonal peak in song coincides with the seasonal trough in day length and sighting-based evidence of whales leaving Monterey Bay, consistent with seasonal migration. During the seasonal song peak, diel variation shows maximum occurrence at night (69% of the time), decreasing during dawn and dusk (52%), and further decreasing with increasing solar elevation during the day, reaching a minimum near solar noon (30%). Song occurrence increased 44% and 55% between successive years. Sighting data within the acoustic detection range of the hydrophone indicate that variation in local population density was an unlikely cause of this large interannual variation. Hydrographic data and modeling of acoustic transmission indicate that changes in neither habitat occupancy nor acoustic transmission were probable causes. Conversely, the positive interannual trend in song paralleled major ecosystem variations, including similarly large positive trends in winddriven upwelling, primary productivity, and krill abundance. Further, the lowest song occurrence during the first year coincided with anomalously warm ocean temperatures and an extremely toxic harmful algal bloom that affected whales and other marine mammals in the region. These major ecosystem variations may have influenced the health and behavior of humpback whales during the study period.David and Lucile Packard FoundationCentral and Northern California Ocean Observing SystemMonterey Accelerated Research System (MARS)NOAANOAA ECOHABJPRDECFPCJTPJTPCWRMKBBNOAA NA16NOS0120021NOAA ECOHAB Program (NA11NOS4780030NSF Award 151475

    Humpback whale song occurrence reflects ecosystem variability in feeding and migratory habitat of the northeast Pacific.

    No full text
    This study examines the occurrence of humpback whale (Megaptera novaeangliae) song in the northeast Pacific from three years of continuous recordings off central California (36.713°N, 122.186°W). Song is prevalent in this feeding and migratory habitat, spanning nine months of the year (September-May), peaking in winter (November-January), and reaching a maximum of 86% temporal coverage (during November 2017). From the rise of song in fall through the end of peak occurrence in winter, song length increases significantly from month to month. The seasonal peak in song coincides with the seasonal trough in day length and sighting-based evidence of whales leaving Monterey Bay, consistent with seasonal migration. During the seasonal song peak, diel variation shows maximum occurrence at night (69% of the time), decreasing during dawn and dusk (52%), and further decreasing with increasing solar elevation during the day, reaching a minimum near solar noon (30%). Song occurrence increased 44% and 55% between successive years. Sighting data within the acoustic detection range of the hydrophone indicate that variation in local population density was an unlikely cause of this large interannual variation. Hydrographic data and modeling of acoustic transmission indicate that changes in neither habitat occupancy nor acoustic transmission were probable causes. Conversely, the positive interannual trend in song paralleled major ecosystem variations, including similarly large positive trends in wind-driven upwelling, primary productivity, and krill abundance. Further, the lowest song occurrence during the first year coincided with anomalously warm ocean temperatures and an extremely toxic harmful algal bloom that affected whales and other marine mammals in the region. These major ecosystem variations may have influenced the health and behavior of humpback whales during the study period

    Organizational Decline - A Synthesis of Insights from Organizational Ecology, Path Dependence and the Resource-Based View

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