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

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

Tying Policy to System: Does the Ross Sea Region Marine Reserve Protect Transport Pathways Connecting the Life History of Antarctic Toothfish?

A central objective of the Ross Sea region Marine Protected Area (MPA) is to protect areas important to the life cycle of Antarctic toothfish (Dissostichus mawsoni), a top fish predator and by far the region’s most important commercial species. Juvenile toothfish predominate in deep basins along the inner continental shelf, whereas adults are found mostly along the continental slope and spawning areas on the Pacific-Antarctic Ridge. The inner basins connect to the continental slope via glacial troughs and predictable transport along each trough results in exchange with the Antarctic Slope Current as it flows westward. From the slope, two transport pathways, an eastern one from Iselin Bank and a western one that turns cyclonically along the flank of the Southeast Indian Ridge, connect northward to the Pacific-Antarctic Ridge, where the northern arm of the Ross Gyre and the Antarctic Circumpolar Current flow eastward. Using a circulation model to compare transport pathways connecting toothfish life history areas, we consider which inshore basins are likely most important in contributing to adult spawning aggregations; how transport pathways from each may be expected to influence distributions along the continental slope and Pacific-Antarctic Ridge; and how zonal transport pathways may promote export to areas downstream of the marine reserve. Although the MPA protects some critical life history pathways for toothfish, others remain vulnerable to commercial fishing, and we argue that those in adjacent areas along the Iselin Bank, Pacific-Antarctic Ridge and the Amundsen Sea might usefully be protected, discussing the range of policy instruments available. We also recommend consideration of transport pathways in deliberations for a proposed network of Southern Ocean MPAs, introducing a system-based tool using chemical tracers in otoliths that can test for toothfish movement between areas connected along the Antarctic Slope Current and Antarctic Circumpolar Current

A Summary of United States Research and Monitoring in Support of the Ross Sea Region Marine Protected Area

Due to the remarkable ecological value of the Ross Sea, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) adopted a large-scale Ross Sea region marine protected area (RSRMPA) in 2016. Since then, many CCAMLR Members have conducted research and monitoring in the region. In 2021, the U.S. Ross Sea science community convened a workshop to collate, synthesize, and coordinate U.S. research and monitoring in the RSRMPA. Here we present workshop results, including an extensive synthesis of the peer-reviewed literature related to the region during the period 2010&ndash;early 2021. From the synthesis, several things stand out. First, the quantity and breadth of U.S. Ross Sea research compares to a National Science Foundation Long Term Ecological Research project, especially involving McMurdo Sound. These studies are foundational in assessing effectiveness of the RSRMPA. Second, climate change and fishing remain the two factors most critical to changing ecosystem structure and function in the region. Third, studies that integrate ecological processes with physical oceanographic change continue to be needed, especially in a directed and coordinated research program, in order to effectively separate climate from fishing to explain trends among designated indicator species</div

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

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

Organizational perspectives on sustainable ocean governance: A multi-stakeholder, meta-organization model of collective action

Although scholars have thoroughly explored theories and practices of formal and informal governance for oceans, most of the research has concentrated on interactions among individuals, or organizations within a sector. The emerging literature from management science argues that meta-organizations, organizations which members are themselves organizations, and especially cross-sectoral meta-organizations, may be a critical concept for scientists, public decision makers, managers, local communities and other actors in ocean governance. A meta-organization&rsquo;s main attributes (i.e., bringing together different formal organizations, consensus-based decision making process, little to no hierarchy, diversity of membership, information-production and collective capacity building and self-regulation mechanisms) can foster critically necessary collaborative behaviors among competitors and across sectors. Here we review key concepts regarding meta-organizations, study six examples of meta-organizations in marine systems, and outline how these advances in management and policy could foster cooperation rather than competition within and among sectors in ocean governance. Meta-organization thinking therefore can help us understand, but also frame and encourage, cross-sectoral collective actions that are solutions-oriented.</p

Does Large-Scale Ocean Circulation Structure Life History Connectivity in Antarctic Toothfish (Dissostichus mawsoni)?

A multidisciplinary approach incorporating otolith chemistry, age data, and numerical Lagrangian particle simulations indicated a single, self-recruiting population of Antarctic toothfish (Dissostichus mawsoni) in the Southeast Pacific Basin (SPB) and Ross Sea, with a life history structured by the large-scale circulation. Chemistry deposited prior to capture along otolith edges demonstrated strong environmental heterogeneity, yet the chemistry in otolith nuclei, deposited during early life, showed no differences. Age data showed only adult fish in catches on the Pacific-Antarctic Ridge in the SPB and structuring of life stages consistent with transport pathways from the northern Ross Sea. Lagrangian particle simulations predicted that early life stages following the flow in the SPB would be transported to areas in the Ross Sea where juveniles are caught, whereas the circulation would facilitate adult movement along the shelf slope and back into the SPB where spawning adults are caught. These results suggest that successfully spawning fish spend only a part of their adult life history in the Ross Sea, areas in the eastern Ross Sea contribute disproportionately to the spawning population, and areas in the southwestern Ross Sea may supply fisheries in the southern Indian Ocean

High-resolution satellite imagery meets the challenge of monitoring remote marine protected areas in the Antarctic and beyond

Remote, high-latitude oceans can prove challenging for the designation and implementation of marine protected areas (MPAs), partly due to issues in monitoring inaccessible localities and large spatial scales. A lack of protection combined with damage from growing human activities has contributed to the degradation of some of the Earth’s richest marine biodiversity and highlights the urgent need to support improved marine conservation. High-resolution satellite imagery (VHR; 0.3–0.6 m spatial resolution) provides a much-needed tool for monitoring sentinel species in remote oceans, which would strengthen current and future MPA research and monitoring programs across the globe. This perspective specifies how recent advances in VHR studies have contributed to knowledge regarding occurrence, habitat suitability, and abundance of mesopredators in the Southern Ocean. We demonstrate how knowledge gained through VHR offers a cost-effective and easily accessible method for collecting previously unobtainable data to inform a representative network of Southern Ocean MPAs, and how the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) could utilize this technology. As VHR and automated detection algorithms continue to improve, we showcase a promising opportunity to use these methods to complement current research and monitoring efforts, thus strengthening MPA efforts in the Southern Ocean and beyond.https://wileyonlinelibrary.com/journal/conlam2023Zoology and Entomolog

Monte Carlo-based lung cancer treatment planning incorporating PET-defined target volumes

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135172/1/acm20065.pd

Reaching consensus for conserving the global commons: The case of the Ross Sea, Antarctica

In October 2016, the international community made history by adopting the world's largest marine protected area in the Ross Sea, Antarctica&mdash;by consensus. Achieving this feat required trade‐offs and compromise among the 24‐Member States (plus the European Union) comprising the Commission for the Conservation of Antarctic Marine Living Resources. The process took 5 years of intense international negotiations and more than 10 years of scientific planning. Based on interviews with national delegations and other stakeholders, 5 years of participatory observation of Commission meetings (2012&ndash;2016), and analysis of hundreds of documents, we present unique insights that explain the conditions that stalled or facilitated the adoption of the Ross Sea MPA. These included economic interests, geopolitics, an erosion of trust, high‐level diplomacy, and the compromises that were ultimately necessary. We reflect on lessons learned as the world considers how to achieve future large‐scale conservation successes in the global commons.</p

Assessing Trade-Offs in Large Marine Protected Areas

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