Implications of Allee effects for fisheries management in a changing climate: evidence from Atlantic cod
Winter, Anna Marie ; Richter, Andries ; Eikeset, Anne Maria - \ 2020
Ecological Applications 30 (2020)1. - ISSN 1051-0761
Allee effect - Atlantic cod - climate - collapse - fisheries management - hysteresis - marginal effect - proactive management - recovery - regime shift - resilience - tipping points
There are concerns that increasing anthropogenic stressors can cause catastrophic transitions in ecosystems. Such shifts have large social, economic, and ecological consequences and therefore have important management implications. A potential mechanism behind these regime shifts is the Allee effect, which describes the decline in realized per capita growth rate at small population density. With an age-structured population model for Atlantic cod, Gadus morhua, we illustrate how interactions between human-induced stressors, such as fishing and climate change, can worsen the impact of an Allee effect on populations by promoting hysteresis. Therefore, the risk of population collapse and recovery failure is exacerbated and the success of preventing and reverting collapse depends on the climate regime. We find that, in presence of the Allee effect, a fishing moratorium is only sufficient for recovery when sea surface temperature rise remains within 2°C and fishing is restricted within 10 yrs. If sea surface temperature rises beyond 2°C, even immediate banning of fishing is not sufficient to guarantee recovery. If fishing is not fully banned and a residual fishing pressure remains, the probability of recovery is further decreased, also in the absence of an Allee effect. The results underscore the decisive role of Allee effects for the management of depleted populations in an increasingly human-dominated world. Once the population collapses and its growth rate is suppressed, rebuilding measures will be squandered and collapse will very likely be irreversible. We therefore emphasize the need for proactive management involving precautionary, adaptive measures and reference points. Our studies shows that climate change has the potential to strengthen Allee effects, which could increasingly challenge fisheries management.
The impact of Russian sanctions on the return of agricultural commodity futures in the EU
Klomp, Jeroen - \ 2020
Research in International Business and Finance 51 (2020). - ISSN 0275-5319
Agricultural commodities - Futures return - Pro-Russian conflict - Sanctions
During the last conflict between Russia and the Ukraine in 2014, the EU imposed various multilateral sanctions on Russia. As a response, Russia retaliated these measures by banning the agricultural imports from the EU. This study explores whether the retaliation sanctions taken by Russia were already expected by investors or came as a complete surprise. For this purpose, I compare the impact of sanction-related news before and after the official announcement of these sanctions by president Putin in August 2014 on the weekly return of a number of agricultural commodity futures traded at two European commodity exchanges. A newly created indicator on sanction-related news is used that is based on the number of articles that have been published in the major European newspapers containing information about the import ban. The main findings clearly point out that before the imposition of the boycott it was already partly anticipated. The publication of sanction-related news caused a significant drop in the futures return of a number of banned agricultural commodities in the weeks prior to the formal announcement.
Marginal selenium deficiency down-regulates inflammation-related genes in splenic leukocytes of the mouse
Kipp, A.P. ; Banning, A. ; Brigelius, R. ; Keijer, J. ; Schothorst, E.M. van - \ 2018
GSE117026 - PRJNA480872 - Mus musculus
Moderate selenium deficiency may lead to an impaired capacity to cope with health challenges. Functional effects of suboptimal selenium intake are not fully known, and biomarkers for an insufficient selenium supply are inadequate. We therefore fed mice diets of moderately deficient or adequate selenium intake for 6 weeks. Changes in global gene expression were monitored by microarray analysis in splenic leukocytes. Genes for four selenoproteins, Sepw1, Gpx1, Selh and Sep15, were the most significantly down-regulated in moderate selenium deficiency, and this was confirmed by quantitative polymerase chain reaction (qPCR). Classification of significantly affected genes revealed that processes related to inflammation, heme biosynthesis, DNA replication and transcription, cell cycle and transport were affected by selenium restriction. Down-regulation by moderate selenium deficiency of specific genes involved in inflammation and heme biosynthesis was confirmed by qPCR. Myeloperoxidase and lysozyme activities were decreased in selenium-restricted leukocytes, providing evidence for functional consequences. Genes for 31 nuclear factor (NF)-κB targets were down-regulated in moderate selenium deficiency, indicating an impaired NF-κB signaling. Together, the observed changes point to a disturbance in inflammatory response. The selenoproteins found here to be sensitive to selenium intake in murine leukocytes might also be useful as biomarkers for a moderate selenium deficiency in humans.
Four selenoproteins, protein biosynthesis, and Wnt signalling are particularly sensitive to limited selenium intake in mouse colon
Kipp, A. ; Banning, A. ; Brigelius, R. ; Keijer, J. ; Schothorst, E.M. van - \ 2018
GSE117025 - PRJNA480871 - Mus musculus
Selenium is an essential micronutrient. Its recommended daily allowance is not attained by a significant proportion of the population in many countries and its intake has been suggested to affect colorectal carcinogenesis. Therefore, microarrays were used to determine how both selenoprotein and global gene expression patterns in the mouse colon were affected by marginal selenium deficiency comparable to variations in human dietary intakes. Two groups of 12 mice each were fed a selenium-deficient (0.086mg Se/kg) or a selenium-adequate (0.15mg Se/kg) diet. After 6wk, plasma selenium level, liver, and colon glutathione peroxidase (GPx) activity in the deficient group was 12, 34, and 50%, respectively, of that of the adequate group. Differential gene expression was analysed with mouse 44K whole genome microarrays. Pathway analysis by GenMAPP identified the protein biosynthesis pathway as most significantly affected, followed by inflammation, Delta-Notch and Wnt pathways. Selected gene expression changes were confirmed by quantitative real-time PCR. GPx1 and the selenoproteins W, H, and M, responded significantly to selenium intake making them candidates as biomarkers for selenium status. Thus, feeding a marginal selenium-deficient diet resulted in distinct changes in global gene expression in the mouse colon. Modulation of cancer-related pathways may contribute to the higher susceptibility to colon carcinogenesis in low selenium status.
Seals in motion : how movements drive population development of harbour seals and grey seals in the North Sea
Brasseur, Sophie Marie Jacqueline Michelle - \ 2017
Wageningen University. Promotor(en): P.J.H. Reijnders, co-promotor(en): G.M. Aarts. - Wageningen : Wageningen University - ISBN 9789463436120 - 176
seals - phoca vitulina - halichoerus grypus - pinnipedia - population biology - animal ecology - wadden sea - netherlands - zeehonden - phoca vitulina - halichoerus grypus - pinnipedia - populatiebiologie - dierecologie - waddenzee - nederland
The harbour seal Phoca vitulina and the grey seal Halichoerus grypus have been inhabitants of the Wadden Sea since millennia. Prehistoric findings indicate the presence of both species around 5000 BC. This changed dramatically in the mid Middle-Ages as around 1500 AC, the grey seal disappeared from the Wadden Sea as a consequence of persecution. With growing hunting pressure, especially in the 20th century and concurrent habitat destruction and pollution, the harbour seals reached all time low numbers in the 1970’s. Banning the hunt in countries around the southern North Sea, limiting pollution and protection from disturbance allowed the harbour seals to slowly recover and the grey seals to return to the Wadden Sea. In this thesis the population trends and inherent dynamics of the recovery for both species is described. Also the movements of individual animals are studied to explain possible mechanisms.
Three years of banning neonicotinoid insecticides based on sub-lethal effects : Can we expect to see effects on bees?
Blacquière, Tjeerd ; Steen, Sjef van der - \ 2017
Pest Management Science 73 (2017)7. - ISSN 1526-498X - p. 1299 - 1304.
Exposure and dose - Honey bees - Neonicotinoids - Pesticide ban - Pollinator declines
The 2013 EU ban of three neonicotinoids used in seed coating of pollinator attractive crops was put in place because of concern about declining wild pollinator populations and numbers of honeybee colonies. It was also concluded that there is an urgent need for good field data to fill knowledge gaps. In the meantime such data have been generated. Based on recent literature we question the existence of recent pollinator declines and their possible link with the use of neonicotinoids. Because of temporal non-coincidence we conclude that declines of wild pollinators and of honeybees are not likely caused by neonicotinoids. Even if bee decline does occur and if there is a causal relationship with the use of neonicotinoids, we argue that it is not possible on such short term to evaluate the effects of the 2013 ban. In order to supply future debate with realistic (field) data and to discourage extrapolating the effects of studies using overdoses that are not of environmental relevance, we propose - in addition to field studies performed by the chemical industry - to use the 'semi-field worst case' treated artificial diet studies approach to free flying colonies in the field. This kind of study may provide realistic estimates for risk and be useful to study realistic interactions with non-pesticide stressors.
Comparative Assessment of Goods and Services Provided by Grazing Regulation and Reforestation in Degraded Mediterranean Rangelands
Papanastasis, Vasilios P. ; Bautista, Susana ; Chouvardas, Dimitrios ; Mantzanas, Konstantinos ; Papadimitriou, Maria ; Garcia Mayor, Angeles ; Koukioumi, Polina ; Papaioannou, Athanasios ; Vallejo, Ramon V. - \ 2017
Land Degradation and Development 28 (2017)4. - ISSN 1085-3278 - p. 1178 - 1187.
carbon sequestration - ecosystem services - forage - grazing management - landscape functional analysis - plant diversity - restoration actions - soil functions
Several management actions are applied to restore ecosystem services in degraded Mediterranean rangelands, which range from adjusting the grazing pressure to the removal of grazers and pine plantations. Four such actions were assessed in Quercus coccifera L. shrublands in northern Greece: (i) moderate grazing by goats and sheep; (ii) no grazing; (iii) no grazing plus pine (Pinus pinaster Aiton) plantation in forest gaps (gap reforestation); and (iv) no grazing plus full reforestation of shrubland areas, also with P. pinaster. In addition, heavy grazing was also assessed to serve as a control action. We comparatively assessed the impact of these actions on key provisioning, regulating and supporting ecosystem services by using ground-based indicators. Depending on the ecosystem service considered, the management actions were ranked differently. However, the overall provision of services was particularly favoured under moderate and no grazing management options, with moderate grazing outranking any other action in provisioning services and the no grazing action presenting the most balanced provision of services. Pine reforestations largely contributed to water and soil conservation and C sequestration but had a negative impact on plant diversity when implemented at the expense of removing natural vegetation in the area. Heavy grazing had the lowest provision of ecosystem services. It is concluded that degraded rangelands can be restored by moderating the grazing pressure rather than completely banning livestock grazing or converting them into pine plantations.
Protecting indigenous land from mining : a study of activist representations of indigenous people, in the context of anti-mining movements, with a focus on an Indian case
Borde, Radhika - \ 2017
Wageningen University. Promotor(en): C. Minca, co-promotor(en): M. Duineveld; B. Blueming. - Wageningen : Wageningen University - ISBN 9789463431880 - 113
mining - indigenous people - land use - protest - relations between people and state - ideology - india - mijnbouw - inheemse volkeren - landgebruik - protest - verhoudingen tussen bevolking en staat - ideologie - india
Support for indigenous peoples has been increasing over the last few decades. This can be seen internationally, as well as in several domestic contexts. The support for indigenous people has been linked to the increasingly prominent impetus to conserve the Earth’s biodiversity and environment. Indigenous people are being recognized for their role in protecting the places in which they live in and that they value in cultural or spiritual terms. This recognition has partly fuelled the support for indigenous lifestyles and the related management of resources. These traditional lifestyles are also presented by activists from within these communities, as a critique of mainstream development. This is echoed by the many activists and activist organizations involved in supporting indigenous people’s causes across the world.
A cause that indigenous people have often rallied around is the resistance towards mining on indigenous land. This is a cause that has attracted a significant amount of support, particularly when the land in question had spiritual or cultural value for an indigenous community. Accordingly, there have been several success stories of resistance towards mining on land that indigenous people believed was sacred, in several different continents. This thesis focuses on such narratives in the Indian context. It examines how, why and to what effect, local and international activists got involved in supporting a movement to protect the Niyamgiri Mountain in east-central India from bauxite extraction by Vedanta Resources, a multi-national mining company. The Niyamgiri Mountain was believed to be sacred by the Dongaria Kondh community which lived there and which is generally understood (though not officially recognized) as an indigenous community. The movement, which this thesis refers to as the Niyamgiri Movement, was finally successful – since the mining project was banned by the Indian government. In addition to a focus on this movement, the thesis also compares this movement with the anti-mining movement on the island of Palawan in the Philippines.
Indigenous peoples constitute minority groups in many of the countries in the Global South. It is also common for governments in the Global South to promote mining as an economic development strategy. This has led to frequent conflicts between indigenous peoples and mining companies. In some of the countries in the Global South, such as the Philippines, indigenous peoples are given official recognition. Whereas in others, such as India, there are affirmative action programs targeting groups claiming indigenous identity, as well as special legislations aimed at protecting their land, although no official recognition of the indigenous identity of these groups exists. Despite this, in contexts such as India there is often a general cultural understanding that groups which claim an indigenous identity are in some way ‘primordial’ – to use a word that translates best from the Indian context, in which the terms Adi Vasi (Original/Primordial Dwellers) or Adim Janajati (Primordial Tribes) are commonly used for such groups.
Given that there is at least some degree of cultural acceptance (if not an official recognition) of the indigenous identity of some of the groups that are entering into conflicts with mining companies, an important question relates to the reasons why local activists may get involved in supporting indigenous struggles against mining and how they may understand indigeneity in this context. Another important question is related to the laws that are applicable in local contexts and which may be used to support the struggles of groups that claim indigenous identity. The Forest Rights Act in India is such a law and the thesis explores how it was used in the context of the Niyamgiri Movement. Finally, it is important to consider how people who are not indigenous and who may not have an activist orientation, can be made to take a sympathetic view of indigenous struggles against mining. In the context of the Niyamgiri Movement in India, this thesis explores how creative representations by activists translated the nature religiosity of the Dongaria Kondhs into familiar terms that mainstream popular discourse in India could identify with.
In the thesis, the comparison of the Niyamgiri Movement in India with the anti-mining movement on the island of Palawan in the Philippines examines the way in which social movements in two different nation-state contexts engage with globalized discourses pertaining to the linkages between indigenous issues and conservation discourses. For a deeper examination of the way indigenous people are represented by globalized popular discourses, the thesis examines how images from Hollywood were used to generate sympathy for the Dongaria Kondhs’ cause in the Niyamgiri Movement. An examination of the international activism which supported the Niyamgiri Movement and which has been effective in bringing about the success of the movement i.e. the banning of the mining project on Niyamgiri, is another important focal point of the thesis.
A commitment towards exploring the activist politics that is relevant to the lives of indigenous peoples has inspired this thesis, which seeks to understand effective activist strategies and identify problematic ones in relation to the protection of land with cultural or spiritual value for indigenous peoples. Keeping this in view, it explores the insights provided by different theories, in order to use these to contribute towards orienting activist practice towards greater effectiveness as well as higher self-reflexivity.
Economic and environmental assessment of irrigation water policies: A bioeconomic simulation study
Lehmann, N. ; Finger, R. - \ 2014
Environmental Modelling & Software 51 (2014). - ISSN 1364-8152 - p. 112 - 122.
stochastic weather generators - evolutionary algorithms - management-practices - modeling approach - crop model - risk - climate - optimization - agriculture - yield
We present a bioeconomic modeling approach that links the biophysical crop growth model CropSyst to an economic decision model at field scale. The developed model is used in conjunction with a genetic algorithm to optimize management decisions in potato production in the Broye catchment (Switzerland) in the context of different irrigation policy scenarios. More specifically, we consider the effects of water bans, water quotas, and water prices on water consumption, profitability, and the financial risks of potato production. The use of a genetic algorithm enables the direct integration of the considered decision variables as management input factors in CropSyst. We employ the farmer's certainty equivalent, measured as the expected profit margin minus a risk premium, as the objective function. Using this methodological framework allows us to consider the potential impacts of policy measures on farmers' crop management decisions due to their effects on both expected income levels and income variability. Our results show that the region's current water policy, which frequently prevents irrigation during hot and dry periods by banning water withdrawal, causes high levels of income risk for the farmer and increases the average water demand in potato production. In contrast, the implementation of an appropriate water quota could significantly decrease water consumption in potato production while allowing the farmer's certainty equivalent to remain at the same level as it is under the current irrigation water policy.
New EU Policies Towards Animal Welfare: The Relative Importance of Pig Castration
Kallas, Z. ; Gil, J.M. ; Panella-Riera, N. ; Blanch, M. ; Tacken, G.M.L. ; Chevillon, P. ; Roest, K. de; Oliver, M.A. - \ 2012
EuroChoices 11 (2012)3. - ISSN 1478-0917 - p. 36 - 43.
Animal welfare is becoming one of the most contentious issues in animal husbandry and meat production industries. We assess the relative importance of animal welfare, with respect to pig castration and the avoidance of boar taint, alongside different attributes of pork meat, amongst consumers in six EU countries. We use the Analytical Hierarchy Process (AHP) as a multi-criteria decision-support method aimed at deconstructing the purchasing decisions of consumers. Our results show that in all surveyed countries, consumers are generally not concerned about the ‘gender of the animal’. This particular attribute represented approximately 10 per cent or less of the final buying decision, while ‘flavour and odour’ was the most important attribute, representing approximately 45 per cent of the final buying decision. The results also demonstrated that pig castration is not necessarily perceived as a relevant aspect of animal welfare. However, any future regulation on banning castration to increase pig welfare could undesirably affect the ‘flavour and odour’ of the meat and thus might negatively impact the most important factor in consumers’ purchasing decisions. Thus, effective public awareness campaigns about the relationship between pig welfare and castration and between castration and sensory meat qualities are needed to help policymakers address the true interests of consumers in future food policies. Le bien-être animal est en train de devenir l’une des questions les plus controversées dans les industries de l’élevage et de la production de viande. Nous évaluons l’importance relative du bien-être animal, en ce qui concerne la castration des porcelets et la suppression de l’odeur de verrat, en termes des différentes caractéristiques de la viande porcine, parmi les consommateurs de six pays de l’Union européenne. Nous utilisons une procédure analytique de hiérarchisation (AHP) comme méthode de prise de décision multicritère visant à déconstruire les décisions des consommateurs en matière d’achat. Nos résultats montrent que dans tous les pays de l’enquête, les consommateurs ne s’intéressent en général pas au sexe de l’animal. Cette caractéristique compte pour environ 10 pour cent ou moins de la décision finale d’achat, tandis que la caractéristique ‘goût et odeur’ domine avec une contribution d’environ 45 pour cent à la décision finale. Les résultats montrent également que la castration des porcelets n’est pas nécessairement perçue comme un aspect pertinent du bien-être animal. Cependant, toute future réglementation interdisant la castration pour améliorer le bien-être des porcs pourrait affecter négativement ‘le goût et l’odeur’ de la viande et donc le facteur d’achat le plus important pour les consommateurs. Il est donc nécessaire de mener des campagnes publiques d’information sur la relation entre le bien-être des porcs et la castration, et entre la castration et la qualité observée de la viande, afin d’aider les décideurs en matière d’action publique à s’intéresser réellement aux préoccupations des consommateurs dans les politiques alimentaires futures. Das Wohlergehen der Tiere entwickelt sich zu einer der umstrittensten Fragen in der Tierzucht und der Fleischproduktion. Wir bewerten die relative Bedeutung des Tierwohls für Verbraucher in sechs EU-Lndern im Hinblick auf Ferkelkastration und Vermeidung von Ebergeruch sowie verschiedene Eigenschaften von Schweinefleisch. Wir bedienen uns eines Analytischen Hierarchieprozesses (AHP), ein multikriterielles Verfahren zur Entscheidungsfindung, das die Kaufentscheidungen von Verbrauchern analysieren soll. Unsere Ergebnisse zeigen, dass sich die Verbraucher in allen betrachteten Lndern im Allgemeinen nicht mit dem Geschlecht der Tiere befassen. Dieses bestimmte Merkmal trug etwa zehn Prozent oder weniger zu der endgültigen Kaufentscheidung bei, whrend “Geschmack und Geruch” das wichtigste Merkmal darstellte und mit etwa 45 Prozent in die endgültige Kaufentscheidung einging. Die Ergebnisse verdeutlichen ebenfalls, dass Ferkelkastration im Hinblick auf das Tierwohl nicht unbedingt als relevant erachtet wird. Zukünftige Bestimmungen in Bezug auf die Kastration zum Schutze der Ferkel könnten sich jedoch in unerwünschter Weise auf den Geschmack und den Geruch des Fleisches auswirken und somit das wichtigste Merkmal für die Kaufentscheidung der Verbraucher negativ beeinflussen. Daher sind effektive Kampagnen zur Schrfung des öffentlichen Bewusstseins über den Zusammenhang zwischen Ferkelschutz und Kastration sowie Kastration und wahrnehmbare Fleischqualitt erforderlich, um die Politikakteure darin zu unterstützen, die wahren Verbraucherinteressen im Rahmen zukünftiger Lebensmittelpolitiken zu vertreten
|Banning cluster bombs : achieving rights through activism
Frerks, G.E. ; Struyk, M. ; Boer, R. - \ 2012
In: Human rights and conflict. Essays in honour of Bas de Gaay Fortman / Boerefijn, I., Henderson, L., Janse, R., Weaver, R., Cambridge : Intersentia - ISBN 9781780680545 - p. 87 - 105.
Marginal selenium deficiency down-regulates inflammation-related genes in splenic leukocytes of the mouse
Kipp, A.P. ; Banning, A. ; Schothorst, E.M. van; Meplan, C. ; Coort, S.L. ; Evelo, C. ; Keijer, J. ; Hesketh, J. ; Brigelius, R. - \ 2012
Journal of Nutritional Biochemistry 23 (2012)9. - ISSN 0955-2863 - p. 1170 - 1177.
kappa-b activation - smooth-muscle-cells - response syndrome - immune-response - glutathione-peroxidase - protein-biosynthesis - t-cell - expression - selenoproteins - macrophages
Moderate selenium deficiency may lead to an impaired capacity to cope with health challenges. Functional effects of suboptimal selenium intake are not fully known, and biomarkers for an insufficient selenium supply are inadequate. We therefore fed mice diets of moderately deficient or adequate selenium intake for 6 weeks. Changes in global gene expression were monitored by microarray analysis in splenic leukocytes. Genes for four selenoproteins, Sepw1, Gpx1, Selh and Sep15, were the most significantly down-regulated in moderate selenium deficiency, and this was confirmed by quantitative polymerase chain reaction (qPCR). Classification of significantly affected genes revealed that processes related to inflammation, heme biosynthesis, DNA replication and transcription, cell cycle and transport were affected by selenium restriction. Down-regulation by moderate selenium deficiency of specific genes involved in inflammation and heme biosynthesis was confirmed by qPCR. Myeloperoxidase and lysozyme activities were decreased in selenium-restricted leukocytes, providing evidence for functional consequences. Genes for 31 nuclear factor (NF)-¿B targets were down-regulated in moderate selenium deficiency, indicating an impaired NF-¿B signaling. Together, the observed changes point to a disturbance in inflammatory response. The selenoproteins found here to be sensitive to selenium intake in murine leukocytes might also be useful as biomarkers for a moderate selenium deficiency in humans.
Scientists: Juvenile Tuna Can Be Fished
Zwieten, P.A.M. van; Kolding, J. - \ 2011
Decades of scientific fishery management advice and volumes of simulation studies may not have been effective at all and might even have damaged stocks and productivity. That is the conclusion of the fishery biologist professor Paul van Zwieten of the Dutch Wageningen University, together with his Danish colleague Jeppe Kolding of the University of Bergen, in a recently published scientific paper. According to Kolding and Van Zwieten the existing models that result in bans on fishing juveniles and quota regulations don’t fit reality and are ‘ecologically vacuous’. Kolding and Van Zwieten base their conclusion on a study of inland small scale fisheries in Africa. “But you can apply the basic conclusion to al fisheries, including tuna”, says Mr. Van Zwieten. “The catch of juvenile tuna in Indonesia might be not as harmful as has been thought. And even the policy of avoiding bycatch might be contra productive.” The conclusions add to the heated debate in circles of marine biologists that question the existing wisdom from single species management models that have been applied in the last 50 years. According to Kolding and Van Zwieten generations of fisheries biologist have been taught the Yield-per-Recruit models to the point that ‘indiscriminate’ fishing methods are by default synonymous with destructive fishing practices. Killing juveniles, as happens in small scale fisheries, has been condemned as a form of depleting the stocks , “so dogmatic that it doesn’t even warrant verification”. “With the increasing focus on discarded bycatch problems in single species industrial fisheries the issue of selectivity has been further highlighted, and much research is devoted to develop increasingly selective fishing methods and exclusion devices”, write Kolding and Van Zwieten. The result of all this is that modern objective for industrial fisheries has become a highly selective kill on targeted species and sizes. But data prove a totally different and more complex reality. Populations experimentally harvested on small sizes produce after only four generations nearly twice as much yield as the populations where only large specimens were harvested. This is clearly in contrast to what the existing model predicts. “Fisheries scientific advice to management, however, is largely oblivious to these evolutionary and ecological studies and continues to reiterate the standard recipe from Yield-per-Recruit models”, write Kolding and Van Zwieten. According to several data, indiscriminate fishing methods might not always be bad from an ecologically point of view as long as it forms part of a fishery that fishes all different age levels in proportion to their natural production. The scientist point out that Lake Kainji - one of the most productive lakes in Africa - since 1996 experienced a 60 % reduction in effort due to banning beach seines and introducing small mesh sizes and mandatory licensing. The only visible result was a corresponding 60 % decrease in yield and no positive response in the individual catch rates as the models assume. It turned a high biologically productive into a less productive system. Instead the most productive inland fisheries like Lake Victoria, are also the most intensely exploited. Open access fisheries prove to result in a certain stable average amount of individual catch. This situation is not unique for African inland fisheries, also investigations in Newfoundland inshore cod fisheries did find similar results. According to both scientists the existing fishery management is based on the long existing misbelieve among ecologists that ecosystems are closed entities in a process towards equilibrium. Human interventions such as fishing are therefore regarded as an external disturbance that affect the productivity of the system. But new dynamic ecology questions this view. Instead it regards ecosystems in a constant and ever changing state of disequilibrium with chaotic fluctuations due climatic variation or human interventions. Another serious misconception is that fish is treated like live stock. But there has been the consistent lack of relationship between adults and recruitment in fisheries science. That indicates that the life history of fish is probably closer to insects and plants. “There is increasing evidence that only show negative ecological effects of adult size selectivity. Everything else being equal, we can safely deduce that the less we select on species and sizes, the more the original composition and structure of a fish community will remain the same”, conclude the biologists. According to Van Zwieten these kind of new fishery management views can also be applied in fisheries like yellowfin tuna and skipjack. For heavily overfished stocks like bigeye tuna, the fishing pressure should nonetheless substantially be reduced regardless the new insights.
Residence time and behaviour of sole and cod in the Offshore Wind farm Egmond aan Zee (OWEZ)
Winter, H.V. ; Aarts, G.M. ; Keeken, O.A. van - \ 2010
IJmuiden [etc.] : IMARES Wageningen UR (Report / IMARES Wageningen UR OWEZ_R_265_T1_20100916) - 50
tong (vis) - gadus morhua - kabeljauw - diergedrag - windmolenpark - milieueffect - dover soles - gadus morhua - cod - animal behaviour - wind farms - environmental impact
‘Noordzeewind’ (a Nuon and Shell Wind Energy consortium) exploits a wind farm with 36 wind turbines off the coast of Egmond aan Zee: the Offshore Wind farm Egmond aan Zee (OWEZ). This project serves to evaluate the economical, technical, ecological and social effects of offshore wind farms in general. To gather knowledge which will result from this project, a Monitoring and Evaluation Program (NSW6MEP) has been developed. Knowledge on environmental impact gained by this project will be made available to all parties involved in the realization of large6scale offshore wind farms. The construction and operation of offshore wind farms may result in possible negative impacts on fish populations, e.g. disturbance by noise or electromagnetic fields around cables, and consequent loss and degradation of habitats. On the other hand, due to the creation of new structures, i.e. additional habitats, that might act as artificial reefs or fish aggregation devices in combination with banning fisheries and shipping within wind farms, also positive impacts on fish populations are possible (Inger et al. 2009). In the latter case, wind farms might act as marine6protected areas or refuges for some fish species. The overall effect of the potential negative and positive impacts of the construction and operation of wind farms for fish is highly dependent on individual behavioural responses of fish to wind farms. This study focuses on exploring the potential benefits of the wind farm OWEZ, i.e. whether the wind farm can act as a refuge against fisheries for some fish species, by studying individual behaviour of fish during the operation phase of the wind farm. A key factor in this is individual residence time of fish within the wind farm. The longer individual fish spend in the wind farm, the stronger potential benefit of wind farms can be expected.
Banning antibiotics, reducing resistance, preventing and fighting infections : White paper on research enabling an 'antibiotic-free' animal husbandry
Kimman, T.G. ; Smits, M.A. ; Kemp, B. ; Wever, P. ; Verheijden, J. - \ 2010
Wageningen [etc.] : Wageningen UR etc. - 72
dierhouderij - intensieve dierhouderij - antibiotica - diergezondheid - volksgezondheid - varkenshouderij - rundveehouderij - pluimveehouderij - animal husbandry - intensive husbandry - antibiotics - animal health - public health - pig farming - cattle husbandry - poultry farming
Resistance of bacteria to antibiotics in animal husbandry is increasing and a point of growing concern. The large use of antibiotics in agriculture undoubtedly leads to the development of antibiotic resistance. This has resulted in a growing public concern on the rise of antibiotic resistance, and in particular on the transmission of resistant bacteria and resistance markers from animals to humans. Large antibiotic use in animal husbandry and antibiotic resistance threatens the health and well being of man and animal through a diminished effectiveness of antibiotic treatments. It causes high costs of – unnecessary or ineffective – antibiotic treatments of animals, and it impairs the image and legitimacy of the intensive livestock sector resulting in a further decline of its societal support and the consumer’s demand for its products. Therefore, politicians and industry will have to make forward looking choices. In this White Paper we present work packages for research lines aimed at eliminating the systematic use of antibiotics in the animal production sector and therewith the emergence of, and selection for, antibiotic resistance. We consider it urgent that the animal husbandry will start producing antibiotic-free wherever and as much as possible. Such a development requires large changes in day-to-day practices, attitudes, and behaviour of all participating stakeholders in animal husbandry. Changes may be enabled by new technical solutions and a design of animal husbandry aimed at optimal disease prevention. It is an illusion that a simple solution will suffice to reduce antibiotic use in animal husbandry. Integrated, multidisciplinary and comprehensive approaches will be absolutely required to make progress. A “search-anddestroy” policy may further be necessary to combat remaining resistant bacteria after the use of antibacterials as selective force has been diminished.
Designing a multiple stakeholder dialogue - initial lessons learnt in navigating through conflicts in the Ghana forestry sector
Duodu, S.K.A. ; Koranteng, W. ; Banning Oppan, R. ; Quaison, K. ; Owusu Ansah, M.S. ; Mckeown, J.P. ; Wit, M. ; Rozemeijer, N.G. - \ 2009
S.n. - 15 p.
The 5 year project (2007 – 2012) to “Develop alternatives for illegal chainsaw lumbering through multi-stakeholder dialogue in Ghana and Guyana” is implemented by a consortium of partners7 to address the degradation of natural forests in both countries. Both Guyana and Ghana show a high incidence of chainsaw lumbering. While in Guyana the practice is legal and controlled, in Ghana it is banned since 19988. However, in many forest fringe communities, chainsaw lumbering is an important source of livelihood despite the high level of conflict associated with the practice. Chainsaw lumbering, which refers to on-site conversion of logs into lumber using chainsaws for commercial purposes, offers livelihood opportunities to large rural groups, who are often living in places that offer few alternatives.
Factors limiting the grain protein content of organic winter wheat in south-eastern France: a mixed-model approach
Casagrande, M. ; David, C. ; Valantin-Morison, M. ; Makowski, D. ; Jeuffroy, M.H. - \ 2009
Agronomy for Sustainable Development 29 (2009)4. - ISSN 1774-0746 - p. 565 - 574.
nitrogen-fertilizer - farming systems - weed management - yield - crop - input - sustainability - number
Organic agriculture could achieve the objectives of sustainable agriculture by banning the use of synthetic fertilizers and pesticides. However, organic crops generally show lower performances than conventional ones. In France, organic winter wheat production is characterized by low grain protein content. There is a crucial need for better understanding the variability of grain protein content, because millers require batches with values over 10.5% of dry matter. Here, a regional agronomic diagnosis was carried out to identify the limiting factors and crop management practices explaining the variability of grain protein content. The studied field network was a set of 51 organic winter wheat plots in south-eastern France. The mixed-model method was used for identifying and ranking the limiting factors and the crop management practices responsible for variation in limiting factors. Our results show that the grain protein content variation was mostly explained by the baking quality grade of the cultivar, crop nitrogen status and weed density at flowering. There was a positive correlation between grain protein content and both crop nitrogen status and weed density. To a lesser extent, climatic factors also explained grain protein content variability. A lower water stress increased grain protein content, whereas an increase in the photothermal quotient and daily temperature over 25 degrees C reduced grain protein content. In south-eastern France, grain protein content of organic winter wheat could be increased by improving fertilization management, using an improved baking quality grade cultivar, choosing a legume fodder crop as preceding crop, or by avoiding late sowing dates.
Four selenoproteins, protein biosynthesis, and Wnt signalling are particularly sensitive to selenium intake in mice colon
Kipp, A. ; Banning, A. ; Schothorst, E.M. van; Meplan, C. ; Schomburg, L. ; Evelo, C. ; Coort, S.L. ; Gaj, S. ; Keijer, J. ; Hesketh, J. ; Brigelius, R. - \ 2009
Molecular Nutrition & Food Research 53 (2009)12. - ISSN 1613-4125 - p. 1561 - 1572.
messenger-rna stability - thioredoxin-like family - glutathione-peroxidase - gene-expression - microarray data - colorectal adenoma - cancer prevention - molecular targets - oxidative stress - selenocysteine
Selenium is an essential micronutrient. Its recommended daily allowance is not attained by a significant proportion of the population in many countries and its intake has been suggested to affect colorectal carcinogenesis. Therefore, microarrays were used to determine how both selenoprotein and global gene expression patterns in the mouse colon were affected by marginal selenium deficiency comparable to variations in human dietary intakes. Two groups of 12 mice each were fed a selenium-deficient (0.086 mg Se/kg) or a selenium-adequate (0.15 mg Se/kg) diet. After 6 wk, plasma selenium level, liver, and colon glutathione peroxidase (GPx) activity in the deficient group was 12, 34, and 50%, respectively, of that of the adequate group. Differential gene expression was analysed with mouse 44K whole genome microarrays. Pathway analysis by GenMAPP identified the protein biosynthesis pathway as most significantly affected, followed by inflammation, Delta-Notch and Wnt pathways. Selected gene expression changes were confirmed by quantitative real-time PCR. GPx1 and the selenoproteins W, H, and M, responded significantly to selenium intake making them candidates as biomarkers for selenium status. Thus, feeding a marginal selenium-deficient diet resulted in distinct changes in global gene expression in the mouse colon. Modulation of cancer-related pathways may contribute to the higher susceptibility to colon carcinogenesis in low selenium status
Impact of eel viruses on recruitment of European eel
Haenen, O.L.M. ; Ginneken, V.J.T. van; Engelsma, M.Y. ; Thillart, G.E.E.J.M. - \ 2009
In: Spawning and Migration of the European Eel / J.C. Rankin G. van den Thillart, S. Dufour, Springer Netherlands (Fish and Fisheries Series 30) - ISBN 9781402090943 - p. 387 - 400.
Eels have an uncommon catadromic life cycle with exceptional migratory patterns to their spawning grounds several thousand kilometres away: the European eel (Anguilla anguilla) travels over 5,500 km to the Sargasso Sea (Schmidt 1923; McCleave and Kleckner 1987; Tesch 1982; Tesch and Wegner 1990); the American eel (A. rostrata) migrates over 4,000 km also to the Sargasso Sea (Castonguay and McCleave 1987; McCleave and Kleckner 1987; Tesch and Wegner 1990); the Australian eel (A. aus-tralis) travels over 5,000 km into the Pacific Ocean to spawn (Jellyman 1987); and the Japanese eel (A. japonica) travels over 4,000 km to an area near the Marianna Islands in the Philippines to spawn (Tsukamoto 1992). Evidently such long distance swimming will place those fishes under extra stress caused by the long starvation period, the high energy cost of the journey, and the many changes in the environment such as salt water, darkness, high pressure, and low temperatures, among other stress factors. Stress is often a basis for disease in eel, especially in intensive eel culture (Haenen and Engelsma, 2005 unpublished finding). Nowadays, global transport of live fishes for aquaculture has facilitated the global spread of pathogens from diseased to healthy stocks. Within the last few decades, aquaculture has become an important production branch in our society. Its global production has more than doubled between 1986 and 1996 in tonnage and value, and over one quarter of human fish consumption at world scale is now produced in aquaculture (Naylor et al. 2000). The Netherlands is one of the leading eel producing & trading countries (Heinsbroek and Kamstra 1995). Blanc (1997) showed that nearly 100 pathogens have been introduced into European water bodies since the introduction of aquaculture. Worldwide many diseases are known in both wild and cultured eel. Parasites, for example trematodes, Anguillicola crassus(nematode), and Myxidium giardi (myxosporean)occur naturally in wild eel populations, mostly in low numbers, without causing mortality (Køie 1988; Van Banning and Haenen 1990; Borgsteede et al. 1999). However, under culture conditions, with eels kept in high densities, they may be harmful. Eel pathogenic bacteria like Vibrio vulnificus, Vibrio anguillarum, Pseudomonas anguillisepticaand Edwardsiella tardamay also cause disease, especially when a stress factor is involved or when the eel is injured (Veenstra et al. 1993; Austin and Austin 1999; Haenen and Davidse 2001). As far as we know, the clinical signs are often more severe under culture conditions compared to in the wild.
The Unspeakable Ban: The Translation of Global Pesticide Governance into Honduran National Regulation
Jansen, K. - \ 2008
World Development 36 (2008)4. - ISSN 0305-750X - p. 575 - 589.
This study examines the transfer of regulatory models from the international to the national level, drawing on a case study of Honduras and its adoption of the International Code of Conduct on the Distribution and Use of Pesticides. A key question concerns why the banning of hazardous pesticides disappears from the national policy agenda in the transfer process. The paper argues that development interventions reinforce a way of framing pesticide risks which prioritizes the scientific assessment of pesticides as a product rather than examining the everyday context in which they are used.