Successful ecosystem-based management of Antarctic krill should address uncertainties in krill recruitment, behaviour and ecological adaptation

Antarctic krill, Euphausia superba, supports a valuable commercial fishery in the Southwest Atlantic, which holds the highest krill densities and is warming rapidly. The krill catch is increasing, is concentrated in a small area, and has shifted seasonally from summer to autumn/winter. The fishery is managed by the Commission for the Conservation of Antarctic Marine Living Resources, with the main goal of safeguarding the large populations of krilldependent predators. Here we show that, because of the restricted distribution of successfully spawning krill and high inter-annual variability in their biomass, the risk of direct fishery impacts on the krill stock itself might be higher than previously thought. We show how management benefits could be achieved by incorporating uncertainty surrounding key aspects of krill ecology into management decisions, and how knowledge can be improved in these key areas. This improved information may be supplied, in part, by the fishery itself

The feeding habits of the Southern elephant seal, Mirounga leonina, at Isla 25 de Mayo/King George Island, South Shetland Islands

The Southern elephant seal (Mirounga leonina) is a major consumer from the Southern Ocean. This species is highly sexually dimorphic and frequently exhibits resource partitioning according to sex and/or age classes. This study analysed the feeding habits of the M. leonina population from Isla 25 de mayo (King George Island) in the spring/summer seasons of 1995/1996–2002/2003. A total of 232 individuals from different sex-age groups were stomach lavaged. The analysis of stomach samples showed that cephalopods were the main prey followed by fish, their frequency of occurrence being 98.1 and 17.9 % respectively. Cephalopods were dominated by the Antarctic glacial squid, Psychroteuthis glacialis, which occurred in 83 % of samples, constituting 57.2 % in numbers and 61.3 % in mass. Octopods were of lesser relevance, occurring in 18 % of samples, but became more important in the diet of male individuals. Juvenile seals fed on a lower variety of cephalopod prey than older ones. This would coincide with the diving pattern characteristic of the different sex-age categories of seals. The predominance of P. glacialis might be associated with the more southerly location of the foraging areas of this population compared to others. Fish were largely represented by the myctophid Gymnoscopelus nicholsi, which occurred in 81.3 % of samples containing otoliths and constituted 76.4 % in numbers and 66.4 % in mass. However, while myctophids may be the dominant fish prey of elephant seals in areas close to the South Shetlands, they would be probably replaced by P. antarcticum as seals migrate towards higher latitudes.Fil: Daneri, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Carlini, A.R.. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Marschoff, Enrique Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Harrington, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Negrete, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Mennucci, J.A.. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Márquez, M. E. I.. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentin

Successful ecosystem-based management of Antarctic krill should address uncertainties in krill recruitment, behaviour and ecological adaptation

This publication and the scientific position of R.D. was supported by a grant awarded to B.M. from the Federal Ministry of Food and Agriculture (BMEL, Project KrillBIS II, grant number 2819HS001) and contribute to the Helmholtz Research Program “Changing Earth—Sustaining our future” of the research field Earth and Environment of the Helmholtz Association, Topic 6, Suptopic 6.1. G.Z. was supported partly by the National Science Foundation of China (NSFC, grant number 41776185) and the National Key R&D Program of China (NKRDPC, grant number 2018YFC1406801). S.L.H., G.A.T., S.E.T., and P.N.T. were supported by the Natural Environment Research Council (NERC) funding to the Ecosystems programme at the British Antarctic Survey. A.A. was supported by NERC through its ‘Climate Linked Atlantic Sector Science’ (NE/R015953/1). A.A. and S.L.H. received additional support from WWF. S.K. was supported by Australian Antarctic Science Program number 4512.Antarctic krill, Euphausia superba, supports a valuable commercial fishery in the Southwest Atlantic, which holds the highest krill densities and is warming rapidly. The krill catch is increasing, is concentrated in a small area, and has shifted seasonally from summer to autumn/winter. The fishery is managed by the Commission for the Conservation of Antarctic Marine Living Resources, with the main goal of safeguarding the large populations of krill-dependent predators. Here we show that, because of the restricted distribution of successfully spawning krill and high inter-annual variability in their biomass, the risk of direct fishery impacts on the krill stock itself might be higher than previously thought. We show how management benefits could be achieved by incorporating uncertainty surrounding key aspects of krill ecology into management decisions, and how knowledge can be improved in these key areas. This improved information may be supplied, in part, by the fishery itself.Publisher PDFPeer reviewe

Neurological disorders in an elderly cohort that experienced past stressful events: a retrospective-prospective study

Background: Psychological stress may be a risk factor for dementia, but the association between exposure to stressful life events and the development of cognitive dysfunction has not been conclusively demonstrated. We hypothesize that if a stressful event has an impact on the sub-jects, its effects would be different in the three diseases. Objective: This study aims to assess the effects of stressful events in senior patients who later de-veloped ischemic stroke, Alzheimer's, or Parkinson's disease. Material and Methods: Together with demographic variables (age, sex, race, socioeconomic and cultural levels), five types of past stressful events, such as death or serious illness of close relatives, job dismissal, change of financial status, retirement, and change of residence, were recorded in 1024 patients with Alzheimer's disease, Parkinson's disease, and ischemic stroke. Time-to-diagnosis (months from the event to the first symptoms: retrospective study) and evolution time (years of follow-up of each patient: prospective study) were recorded. The variance and non-parametric methods were analyzed to the variables time-to-diagnosis and evolution time to analyze differences between these diseases. Results: The demographic variables, such as age, sex, race, economic and cultural levels, were found to be statistically non-significant; differences in the economic level were significant (PParkinson’s disease >Stroke), and minor differences (P<0.05) in evolution time. Conclusion: Differences in time-to-diagnosis between the diseases indicate that the stressful effect of having experienced the death or serious illness of a close relative has an impact on their emer-gence. The measurement of time-to-diagnosis and evolution time proves useful in detecting differences between diseases.Fil: Domínguez, Raúl O.. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Marschoff, Enrique Ricardo. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Oudkerk, Liliana M.. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: de la Ossa Angulo, Luis E.. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Villamizar Pérez, Susana. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Bianchi, Graciela A.. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Repetto, Marisa Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Serra, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentin

World Ocean Assessment II, Chapter 01, Overall summary

KEYNOTE POINTS 1. Understanding of the ocean continues to improve. Innovations in sensors andautonomous observation platforms have substantially increased observations of the ocean. Regional observation programmes have expanded, with better coordination and integration. 2. Some responses for mitigating or reducing pressures and their associated impacts on the ocean have improved since the first World Ocean Assessment. They include the expansion and implementation of management frameworks for conserving the marine environment, including the establishment of marine protected areas and, in some regions, improved management of pollution and fisheries. However, many pressures from human activities continue to degrade the ocean, including important habitats, such as mangroves and coral reefs. Pressures include those associated with climate change; unsustainable fishing, including illegal, unreported and unregulated fishing; the introduction of invasive species; atmospheric pollution causing acidification and eutrophication; excessive inputs of nutrients and hazardous substances, including plastics, microplastics and nanoplastics; increasing amounts of anthropogenic noise; and ill-managed coastal development and extraction of natural resources. 3.There continues to be a lack of quantification of the impacts of pressures and their cumulative effects. A general failure to achieve the integrated management of human uses of coasts and the ocean is increasing risks to the benefits that people draw from the ocean, including in terms of food safety and security, material provision, human health and well-being, coastal safety and the maintenance of key ecosystem services. 4. Improving the management of human uses of the ocean to ensure sustainability will require improved coordination and cooperation to provide capacity-building in regions where it is lacking, innovations in marine technology, the integration of multidisciplinary observation systems, the implementation of integrated management and planning and improved access to, and exchange of, ocean knowledge and technologies. 5.The coronavirus disease (COVID-19) pandemic is having a major effect on many human activities carried out in the ocean. The full implications of the pandemic on human interactions with the ocean are still to be fully assessed.Versión del edito

World Ocean Assessment II, Chapter 02, Approach to the assessment

KEYNOTE POINTS 1. The purpose of the second World Ocean Assessment is to update the first World Ocean Assessment by providing an understanding of changes that have occurred in the global ocean since 2010 and associated trends. 2. The Assessment also provides an overview of understanding of some aspects not fully covered in the first Assessment, such as inputs of anthropogenic noise, marine hydrates, cumulative effects, marine spatial planning and management approaches. 3. The Assessment follows a modified approach to the drivers-pressures-state-impact- response framework, supported through a series of workshops aimed at identifying region-specific information and input for the Assessment, a peer-review process and a process of review by States.Versión del edito