80 research outputs found

    Radiometric age validation and spatial distribution of the Antarctic Toothfish, (Dissostichus mawsoni) : implications for a deep-sea Antarctic fishery

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    Antarctic toothfish (Dissostichus mawsoni) are subject to an increasingly important commercial fishery in the Southern Ocean, yet their life history characteristics and population structure remain largely unknown. In this study, Antarctic toothfish otoliths were obtained from American long-line fishing vessels in the Ross Sea, Antarctica. Age estimates obtained by counting annual growth increments in otolith sections indicate Antarctic toothfish live to at least 39 years of age. Lead-radium dating was used to validate ages up to 27.3 (range 21.7 -34.1) and provided support for ages up to 39 years of age using the methodology applied in this study. Validation also provided support for VBGF parameters, which indicate toothfish grow relatively slowly (k = 0.111; L∞ = 158.9; t₀ = -0.605). Fish ages were then superimposed on a habitat map of the Ross Sea, Antarctica and broken into discrete spatial areas. Differences in age data within these areas was tested using ANOVA. There was a relationship between fish age and maturity increasing with depth; younger, less mature fish were more often found on the shallower continental shelf and older fish were more often found in the deeper regions on the continental slope. However, there was far more variability than expected and other oceanographic and ecological factors likely effect age structure distribution significantly. Older and most mature individuals were found on ridges in the northern Ross Sea, consistent with the hypothesis of an austral summer spawning migration. An effective management strategy might focus on protecting the northern ridge habitat to potentially maintain long-term viability of Antarctic toothfish populations. Additionally, Antarctic toothfish vital rates should be considered before expanding the Ross Sea fishery

    Enhancing Parenting Skills Among Nonresident African American Fathers as a Strategy for Preventing Youth Risky Behaviors

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    This study evaluated the effectiveness of a theoretically based, culturally specific family intervention designed to prevent youth risky behaviors by influencing the parenting attitudes and behaviors of nonresident African American fathers and the parent–child interactions, intentions to avoid violence, and aggressive behaviors of their preadolescent sons. A sample of 158 intervention and 129 comparison group families participated. ANCOVA results indicated that the intervention was promising for enhancing parental monitoring, communication about sex, intentions to communicate, race‐related socialization practices, and parenting skills satisfaction among fathers. The intervention was also beneficial for sons who reported more monitoring by their fathers, improved communication about sex, and increased intentions to avoid violence. The intervention was not effective in reducing aggressive behaviors among sons. Findings are discussed from a family support perspective, including the need to involve nonresident African American fathers in youth risky behavior prevention efforts.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116964/1/ajcp9290.pd

    Assessing Trade-Offs in Large Marine Protected Areas

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    Large marine protected areas (LMPAs) are increasingly being established and have a high profile in marine conservation. LMPAs are expected to achieve multiple objectives, and because of their size are postulated to avoid trade-offs that are common in smaller MPAs. However, evaluations across multiple outcomes are lacking. We used a systematic approach to code several social and ecological outcomes of 12 LMPAs. We found evidence of three types of trade-offs: trade-offs between different ecological resources (supply trade-offs); trade-offs between ecological resource conditions and the well-being of resource users (supply-demand trade-offs); and trade-offs between the well-being outcomes of different resource users (demand trade-offs). We also found several divergent outcomes that were attributed to influences beyond the scope of the LMPA. We suggest that despite their size, trade-offs can develop in LMPAs and should be considered in planning and design. LMPAs may improve their performance across multiple social and ecological objectives if integrated with larger-scale conservation efforts. © 2018 Davies et al

    Age-related changes in auditory and visual interactions in temporal rate perception

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    We investigated how aging affects the integration of temporal rate for auditory flutter (amplitude modulation) presented with visual flicker. Since older adults were poorer at detecting auditory amplitude modulation, modulation depth was individually adjusted so that temporal rate was equally discriminable for 10 Hz flutter and flicker, thereby balancing the reliability of rate information available to each sensory modality. With age-related sensory differences normalized in this way, rate asynchrony skewed both auditory and visual rate judgments to the same extent in younger and older adults. Therefore, reliability-based weighting of temporal rate is preserved in older adults. Concurrent presentation of synchronous 10 Hz flicker and flutter improved temporal rate discrimination consistent with statistically optimal integration in younger but not older adults. In a control experiment, younger adults were presented with the same physical auditory stimulus as older adults. This time, rate asynchrony skewed perceived rate with greater auditory weighting rather than balanced integration. Taken together, our results indicate that integration of discrepant auditory and visual rates is not altered due to the healthy aging process once sensory deficits are accounted for, but that aging does abolish the minor improvement in discrimination performance seen in younger observers when concordant rates are integrated

    Antarctic Climate Change and the Environment: A Decadal Synopsis and Recommendations for Action

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    Scientific evidence is abundantly clear and convincing that due to the current trajectory of human-derived emissions of CO2 and other greenhouse gases, the atmosphere and ocean will continue to warm, the ocean will continue to acidify, atmospheric and ocean circulation patterns will be altered, the cryosphere will continue to lose ice in all forms, and sea level will rise

    Managing for climate resilient fisheries: Applications to the Southern Ocean

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    Climate change is having profound effects on populations of fished species and the ecosystems on which they depend, lending to a growing body of work that advocates for climate resilience to be a priority in fishery management. Here, we provide a comprehensive analysis of the tools needed to manage for climate resiliency. The Antarctic region is among the most vulnerable to climate change, and thus, we then consider climate resilient management tools utilized by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), the body responsible for the management of Antarctic marine living resources as part of the Antarctic Treaty System. We note progress, gaps, and opportunities for implementation. Across the literature, ecosystem-based management was cited as an appropriate tool for climate resilience of marine ecosystems, as was the use of climate model outputs (projections and simulations), marine protected areas (MPAs), and dynamic stock assessments. CCAMLR has a unique position where its Convention effectively mandates the principles of an ecosystem-based precautionary approach for managing fisheries, and many of its Member States have been advocating for climate initiatives within this approach. While CCAMLR has made limited overall progress towards ensuring climate resilience, it has advanced in some areas, such as MPA implementation, developing a risk assessment for krill, and including statements on climate change in fishery reports, although there is much work to be done. While climate change remains a worldwide issue that must be addressed on a global scale, CCAMLR holds the responsibility for adaptively managing Southern Ocean marine living resources for climate resilience

    Protect global values of the Southern Ocean ecosystem

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    The Southern Ocean, which comprises ∼10% of the global ocean, is critically important to the homeostasis of the Earth system, exhibits distinctive marine biodiversity, and has tremendous scientific, diplomatic, and wilderness value. Yet, the region and its suite of global values are critically threatened by climate change, which is exacerbated by commercial fishing, an activity that provides value for relatively few industrial actors and compromises the greater values that the Southern Ocean ecosystem provides to the world. The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), the arm of the Antarctic Treaty System responsible for managing Southern Ocean marine living resources, meets in October–November 2022 and is under pressure to strengthen fisheries management, especially toward climate change resilience. We encourage improved management practices that account for the environmental externalities arising from trade-offs between fishing and the global contribution of the Southern Ocean ecosystem, including under a changing climate.The Pew Charitable Trusts; Biodiversa ASICS. U.R.S. and the University of British Columbia–based Solving Food-Climate-Biodiversity research partnership sponsored by the Social Sciences and Humanities Research Council of Canada.http://www.sciencemag.orghj2023Plant Production and Soil Scienc

    Marine ecosystem assessment for the Southern Ocean: birds and marine mammals in a changing climate

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    The massive number of seabirds (penguins and procellariiformes) and marine mammals (cetaceans and pinnipeds) – referred to here as top predators – is one of the most iconic components of the Antarctic and Southern Ocean. They play an important role as highly mobile consumers, structuring and connecting pelagic marine food webs and are widely studied relative to other taxa. Many birds and mammals establish dense breeding colonies or use haul-out sites, making them relatively easy to study. Cetaceans, however, spend their lives at sea and thus aspects of their life cycle are more complicated to monitor and study. Nevertheless, they all feed at sea and their reproductive success depends on the food availability in the marine environment, hence they are considered useful indicators of the state of the marine resources. In general, top predators have large body sizes that allow for instrumentation with miniature data-recording or transmitting devices to monitor their activities at sea. Development of scientific techniques to study reproduction and foraging of top predators has led to substantial scientific literature on their population trends, key biological parameters, migratory patterns, foraging and feeding ecology, and linkages with atmospheric or oceanographic dynamics, for a number of species and regions. We briefly summarize the vast literature on Southern Ocean top predators, focusing on the most recent syntheses. We also provide an overview on the key current and emerging pressures faced by these animals as a result of both natural and human causes. We recognize the overarching impact that environmental changes driven by climate change have on the ecology of these species. We also evaluate direct and indirect interactions between marine predators and other factors such as disease, pollution, land disturbance and the increasing pressure from global fisheries in the Southern Ocean. Where possible we consider the data availability for assessing the status and trends for each of these components, their capacity for resilience or recovery, effectiveness of management responses, risk likelihood of key impacts and future outlook

    Plasma Biomarker Concentrations Associated With Return to Sport Following Sport-Related Concussion in Collegiate Athletes—A Concussion Assessment, Research, and Education (CARE) Consortium Study

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    Importance: Identifying plasma biomarkers associated with the amount of time an athlete may need before they return to sport (RTS) following a sport-related concussion (SRC) is important because it may help to improve the health and safety of athletes. Objective: To examine whether plasma biomarkers can differentiate collegiate athletes who RTS in less than 14 days or 14 days or more following SRC. Design, Setting, and Participants: This multicenter prospective diagnostic study, conducted by the National Collegiate Athletics Association–Department of Defense Concussion Assessment, Research, and Education Consortium, included 127 male and female athletes who had sustained an SRC while enrolled at 6 Concussion Assessment, Research, and Education Consortium Advanced Research Core sites as well as 2 partial–Advanced Research Core military service academies. Data were collected between February 2015 and May 2018. Athletes with SRC completed clinical testing and blood collection at preseason (baseline), postinjury (0-21 hours), 24 to 48 hours postinjury, time of symptom resolution, and 7 days after unrestricted RTS. Main Outcomes and Measures: A total of 3 plasma biomarkers (ie, total tau protein, glial fibrillary acidic protein [GFAP], and neurofilament light chain protein [Nf-L]) were measured using an ultrasensitive single molecule array technology and were included in the final analysis. RTS was examined between athletes who took less than 14 days vs those who took 14 days or more to RTS following SRC. Linear mixed models were used to identify significant interactions between period by RTS group. Area under the receiver operating characteristic curve analyses were conducted to examine whether these plasma biomarkers could discriminate between RTS groups. Results: The 127 participants had a mean (SD) age of 18.9 (1.3) years, and 97 (76.4%) were men; 65 (51.2%) took less than 14 days to RTS, and 62 (48.8%) took 14 days or more to RTS. Linear mixed models identified significant associations for both mean (SE) plasma total tau (24-48 hours postinjury, <14 days RTS vs ≥14 days RTS: −0.65 [0.12] pg/mL vs −0.14 [0.14] pg/mL; P = .008) and GFAP (postinjury, 14 days RTS vs ≥14 days RTS: 4.72 [0.12] pg/mL vs 4.39 [0.11] pg/mL; P = .04). Total tau at the time of symptom resolution had acceptable discrimination power (area under the receiver operating characteristic curve, 0.75; 95% CI, 0.63-0.86; P < .001). We also examined a combined plasma biomarker panel that incorporated Nf-L, GFAP, and total tau at each period to discriminate RTS groups. Although the analyses did reach significance at each time period when combined, results indicated that they were poor at distinguishing the groups (area under the receiver operating characteristic curve, <0.7). Conclusions and Relevance: The findings of this study suggest that measures of total tau and GFAP may identify athletes who will require more time to RTS. However, further research is needed to improve our ability to determine recovery following an SRC.This publication was made possible with support from the Grand Alliance Concussion Assessment, Research, and Education (CARE) Consortium, funded, in part by the NCAA and the Department of Defense. The US Army Medical Research Acquisition Activity, 820 Chandler St, Ft Detrick, MD 21702, is the awarding and administering acquisition office. This work was supported by the Office of the Assistant Secretary of Defense for Health Affairs through the Psychological Health and Traumatic Brain Injury Program under award No. W81XWH-14-2-0151

    A scientific synthesis of marine protected areas in the United States: status and recommendations

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    Marine protected areas (MPAs) are a key tool for achieving goals for biodiversity conservation and human well-being, including improving climate resilience and equitable access to nature. At a national level, they are central components in the U.S. commitment to conserve at least 30% of U.S. waters by 2030. By definition, the primary goal of an MPA is the long-term conservation of nature; however, not all MPAs provide the same ecological and social benefits. A U.S. system of MPAs that is equitable, well-managed, representative and connected, and includes areas at a level of protection that can deliver desired outcomes is best positioned to support national goals. We used a new MPA framework, The MPA Guide, to assess the level of protection and stage of establishment of the 50 largest U.S. MPAs, which make up 99.7% of the total U.S. MPA area (3.19 million km2). Over 96% of this area, including 99% of that which is fully or highly protected against extractive or destructive human activities, is in the central Pacific ocean. Total MPA area in other regions is sparse – only 1.9% of the U.S. ocean excluding the central Pacific is protected in any kind of MPA (120,976 km2). Over three quarters of the non-central Pacific MPA area is lightly or minimally protected against extractive or destructive human activities. These results highlight an urgent need to improve the quality, quantity, and representativeness of MPA protection in U.S. waters to bring benefits to human and marine communities. We identify and review the state of the science, including focal areas for achieving desired MPA outcomes and lessons learned from places where sound ecological and social design principles come together in MPAs that are set up to achieve national goals for equity, climate resilience, and biodiversity conservation. We recommend key opportunities for action specific to the U.S. context, including increasing funding, research, equity, and protection level for new and existing U.S. MPAs
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