SABIIA - Sistema Aberto e Integrado de Informação em Agricultura (Sabiia)

Kell, L. T.; Fromentin, Jean-marc.

This paper presents an example of Management Strategy Evaluation (MSE) for Mediterranean and East Atlantic bluefin tuna using the FLR open source framework. Scenarios corresponding to alternative plausible hypotheses about the stock dynamics were used to evaluate alternative management strategies and to test their robustness to implementation error e.g. catch mis-reporting. The strategies evaluated correspond to i) harvest control rule (HCR) based upon F0.1 (a proxy for FMSY ) with an objective of restoring the stock to a level that would “ permit the maximum sustainable catch” and ii) a reduction of fishing mortality on immature fish. The main conclusions were that the F0.1 HCR alone would not result in the recovery of the stock in the next 15 years and...

Tipo: Text

Palavras-chave: Thunnus thynnus; Management plans; Management strategy evaluation; Simulation model.

Ano: 2009

URL: http://archimer.ifremer.fr/doc/00194/30477/28884.pdf

An attempt to evaluate the recent management regulations of the east Atlantic and Mediterranean bluefin tuna stock through a simple simulation model

ANALYSIS OF CHANGING METHODS OF VERTICAL COORDINATION IN THE PORK INDUSTRY

Fromentin, Jean-marc.

This manuscript proposes a simple simulation model to investigate the implications to the resources of the recent management regulations adopted for the East Atlantic and Mediterranean bluefin tuna stock. If perfectly implemented, the new regulations on minimum size and closed fishing areas mostly lead to a change in the selectivity pattern which moves towards older fish, so decreasing growth-overfishing. The potential sustainable yields therefore considerably increase (almost double in comparison to those that would be obtained without the new regulations) while the SSB can rapidly reach 20% of the virgin SSB. An error of 20% in the implementation of these new regulations affects their efficiencies and does not seem to allow the rebuilding of the SSB at a...

Tipo: Text

Palavras-chave: Bluefin tuna; Management regulations; Stock rebuilding; Simulation model.

Ano: 2008

URL: http://archimer.ifremer.fr/doc/00192/30297/28787.pdf

Martinez, Stephen W.; Smith, Kevin E.; Zering, Kelly D..

This study examines the motivation behind contracts and vertical integration in the pork industry, and simulates the effects of potential improvements in coordination. Incentives related to lowering costs of measuring and sorting hogs, and protecting against opportunistic behavior associated with specific assets, can result in hog quality improvements. A framework for simulating the effects of increased coordination through contracts and vertical integration was developed and used to evaluate potential improvements in leanness. Although simulations suggest only modest changes in pork prices and supplies, gains in consumers' surplus could be substantial for larger demand shifts due to quality improvements.

Tipo: Journal Article

Palavras-chave: Contracts; Hogs; Lean pork; Simulation model; Vertical coordination; Vertical integration; Industrial Organization; Livestock Production/Industries.

Ano: 1998

URL: http://purl.umn.edu/15561

Assessment of the Impact of Avian Influenza Related Regulatory Policies on Poultry Meat Trade and Welfare

Wieck, Christine; Schlueter, Simon W.; Britz, Wolfgang.

We use two methodological approaches to analyze avian influenza related quarantine measures. First, a Heckman type gravity model is used to estimate the trade impact and second, a spatial partial equilibrium simulation model is developed to simulate welfare changes. The simulation model considers spread and transmission risk according to the disease status of the importing country as well as parameter uncertainty of the calibrated coefficients by using a Monte Carlo approach. The econometric results show that the principle of regionalization is preferred to import trade bans for uncooked meat. The simulation results verify the negative welfare impact of currently implemented regulatory policies and indicate that significant trade diversion effects...

Tipo: Working Paper

Palavras-chave: Animal disease; Quarantine measure; Non-tariff measure; Welfare; Gravity model; Simulation model; Agricultural and Food Policy; Demand and Price Analysis; F14; F17; Q11; Q17; Q18.

Ano: 2012

URL: http://purl.umn.edu/122022

Calopteryx Damselfly Dispersions Arising from Multiscale Responses to Landscape Structure

Jonsen, Ian; University of Alberta; jonseni@em.agr.ca; Taylor, Philip D; Acadia University; ptaylor@resalliance.org.

Using spatially explicit simulation models, we explored the extent to which fine-scale (i.e., meters to tens of meters) movement behaviors could be used to predict broader scale patterns of distribution on heterogeneous landscapes. Our models were tailored by empirical data on Calopterygid damselfly movements on three types of landscapes that differed in amount of forest habitat. Surveys of the two congeneric damselflies, Calopteryx aequabilis and Calopteryx maculata, demonstrated that both species occupied stream and forest habitats on forested and partially forested landscapes, but were found primarily along streams on nonforested landscapes. Simulation models whose parameters were derived using empirical movement data for both species showed that...

Tipo: Peer-Reviewed Reports

Palavras-chave: Calopteryx aequabilis; Calopteryx maculata; Connectivity; Damselflies; Landscape structure; Movement behaviors; Multiscale dispersion; Patch boundary permeability; Patch viscosity; Simulation model; Spatial scale.

Ano: 2000

Can we detect the effects of environmental variations on fish populations through VPA outputs? the North Atlantic albacore case

Kell, Laurence T; Fromentin, Jean-marc; Ortiz De Zarate, Victoria; Arrizabalaga, Haritz.

Past studies have indicated that numbers-at-age 1 of albacore may be correlated with the winter NAO index in the previous year. Two main hypotheses have been stressed to explain such observation, i.e. an impact of the NAO on the recruitment or on migration patterns and consequently in the availability and catchability of specific age classes to the surface fishery. The objective of the present paper is to test whether such processes can be distinguished using VPA outputs. We first computed simple cross-correlations between the NAO at various lags, catches-at-age, Numbers-atage and F-at-age estimated in the last assessment. Since results were inconclusive, simulations were undertaken. The results showed that the probability of detecting spurious...

Tipo: Text

Palavras-chave: Thunnus alalunga; North Atlantic Oscillation; Simulation model; Virtual population analysis; Correlation coefficient; NAO.

Ano: 2005

URL: http://archimer.ifremer.fr/doc/00194/30503/28913.pdf

Computational modeling for irrigated agriculture planning. Part I: general description and linear programming

REA

Borges Júnior,João C. F.; Ferreira,Paulo A.; Andrade,Camilo L. T.; Hedden-Dunkhorst,Bettina.

Linear programming models are effective tools to support initial or periodic planning of agricultural enterprises, requiring, however, technical coefficients that can be determined using computer simulation models. This paper, presented in two parts, deals with the development, application and tests of a methodology and of a computational modeling tool to support planning of irrigated agriculture activities. Part I aimed at the development and application, including sensitivity analysis, of a multiyear linear programming model to optimize the financial return and water use, at farm level for Jaíba irrigation scheme, Minas Gerais State, Brazil, using data on crop irrigation requirement and yield, obtained from previous simulation with MCID model. The linear...

Tipo: Info:eu-repo/semantics/article

Palavras-chave: Irrigation requirement; Financial return; Simulation model.

Ano: 2008

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162008000300008

Effects of Fishing Tourism in a Coastal Municipality: a Case Study from Risør, Norway

Moksness, Erlend; Institute of Marine Research; moksness@imr.no; Lagaillarde, Guillaume ; 1point2;; Mikkelsen, Eirik ; NORUT, Norway;.

Tipo: Peer-Reviewed Reports

Palavras-chave: Local cod stock; Local economic benefits; Local management instruments; Marine fishing tourism; Simulation model.

Ano: 2011

Estimated Impacts of a Potential U.S.-Mexico Preferential Trading Agreement for the Agricultural Sector

Krissoff, Barry; Neff, Liana; Sharples, Jerry A..

We develop a three region - U.S., Mexico, and Rest-of-World - simulation model to analyze the effects on the agricultural sector of a potential preferential trading arrangement (PTA) between Mexico and the United States. The simulation exercises indicate that two-way agricultural trade increases and welfare improves in the United States and Mexico from a bilateral preferential agreement on agricultural products. Our results show that when border protection is eliminated by the United States and Mexico, bilateral agricultural trade expands by over 15 percent. Relative to the size of the two agricultural sectors, however, the overall impact is very small for the U.S. agricultural sector but there is a more significant adjustment for Mexican agriculture.

Evaluation of the performance and robustness of VPA-based stock assessment and MSY-based management strategy to process error: the Atlantic bluefin tuna case study

Palavras-chave: Preferential trading arrangements; Simulation model; Agricultural trade; United States and Mexico; International Relations/Trade.

Ano: 1992

URL: http://purl.umn.edu/51135

Fromentin, Jean-marc; Kell, Laurence T.

An integrative simulation framework was built to evaluate the consequences of variability attributable to changes in carrying capacity or the stock’s migration pattern of Atlantic bluefin tuna on the ICCAT stock assessment and management procedures. We also evaluated the performances of stock assessment methods with respect to their ability to provide good estimates of MSY, FMSY and BMSY and tested the robustness of the current ICCAT management strategy to uncertainty about the true dynamics and historical exploitation levels. The results clearly indicate that the VPA performances were seriously impaired if the long-term variations in catches are due to changes in migration/availability. There is further considerable confounding between the underlying...

Tipo: Text

Palavras-chave: Thunnus thynnus; Stock assessment; VPA; Biological reference points; MSY; Management strategy; Simulation model.

Ano: 2009

URL: http://archimer.ifremer.fr/doc/00192/30295/28786.pdf

Liability Risks in Agri-food Supply Chains: The Case of Wet Feed

Meuwissen, Miranda P.M.; Van Asseldonk, Marcel A.P.M.; Huirne, Ruud B.M..

Recent animal feed crises caused substantial damage throughout food supply chains and, consequently, initiated debates on the liability insurance cover of animal feed companies. In this framework, a quantitative risk analysis for wet feed producers in the Netherlands is presented. The simulation model developed is parameterised by among others data from three Dutch wet feed companies reflecting about 45% of the wet feed market in the Netherlands. The model addresses direct damage up to farm level. Default outcomes per crisis show that the number of contaminated farms is expected to be 117, with a variation from 19 farms in the 5% percentile to 331 farms in the 95% percentile. Projected direct damage per crisis is on average Euro 0.9 million, ranging from...

Tipo: Conference Paper or Presentation

Palavras-chave: Contamination risk; Simulation model; Direct damage; Agribusiness.

Ano: 2008

URL: http://purl.umn.edu/44396

Local vs. Landscape Effects of Woody Field Borders as Barriers to Crop Pest Movement

Bhar, Rod; Ottawa-Carleton Institute of Biology; rbhar@ccs.carleton.ca; Fahrig, Lenore; Carleton University; lfahrig@ccs.carleton.ca.

Maintenance of woody borders surrounding crop fields is desirable for biodiversity conservation. However, for crop pest management, the desirability of woody borders depends on the trade-off between their effects at the local field scale and the landscape scale. At the local scale, woody borders can reduce pest populations by increasing predation rates, but they can also increase pest populations by providing complementary habitats and reducing movement rate of pests out of crop fields. At the regional scale, woody borders can reduce pest populations by reducing colonization of newly planted crop fields. Our objective was to develop guidelines for maximizing pest control while maintaining woody borders in the landscape. We wished to determine the...

Tipo: Peer-Reviewed Reports

Palavras-chave: Biodiversity; Crop pest; Crop rotation; Dispersal; Fencerow; Field margin; Hedgerow; Patchy population; Pest control; Shelterbelt; Simulation model; Woody border..

Ano: 1998

Managing the Cumulative Impacts of Land Uses in the Western Canadian Sedimentary Basin: A Modeling Approach

Schneider, Richard, R.; Ministik Environmental Consulting; rschneid@icrossroads.com; Stelfox, J. Brad; Forem Technologies; bstelfox@telusplanet.net; Boutin, Stan; Department of Biological Sciences, University of Alberta; Stan.Boutin@ualberta.ca; Wasel, Shawn; Alberta-Pacific Forest Industries Inc.; waselsh@alpac.ca.

This case study from northeastern Alberta, Canada, demonstrates a fundamentally different approach to forest management in which stakeholders balance conservation and economic objectives by weighing current management options from the point of view of their long-term effects on the forest. ALCES®, a landscape-scale simulation model, is used to quantify the effects of the current regulatory framework and typical industrial practices on a suite of ecological and economic indicators over the next 100 yr. These simulations suggest that, if current practices continue, the combined activities of the energy and forestry industries in our 59,000 km2 study area will cause the density of edge of human origin to increase from 1.8 km/km 2 to a maximum of...

Tipo: Peer-Reviewed Reports

Palavras-chave: Alberta; Western Canadian Sedimentary Basin; Boreal forest; Cumulative industrial impacts; Forestry industry; Integrated resource management; Petroleum industry; Simulation model.

Ano: 2003

Partial Reform of World Rice Trade: Implications for the U.S. Rice Sector

Haley, Stephen L..

This paper analyzes the consequences for the United States of a partial reform of world rice trade. It is argued that likely trade reform would occur in the japonica rice producing countries of Japan, South Korea, Taiwan, and the European Community. Multilateral rice trade liberalization would have strong effects for medium grain rice in the United States. The strength of these effects might not be felt for a couple of years after the liberalization has begun because of minimal Japanese imports in the first couple of years of liberalization. U.S. rice millers will likely benefit more than producers. California producers would be the major beneficiaries of more open world rice markets.

Rendimiento potencial del maíz en el Distrito de Riego 063 Guasave, Sinaloa bajo diferentes fechas de siembra aplicando el modelo hybrid maize.

Palavras-chave: Trade liberalization; Rice; Japonica rice; Agricultural trade; Simulation model; Crop Production/Industries; International Relations/Trade.

Ano: 1991

URL: http://purl.umn.edu/51138

Colegio de Postgraduados

Aguirre Rojo, José Anastacio.

Gracias al desarrollo de herramientas de simulación, como medio de obtención de soluciones prácticas, aplicadas a problemas de ingeniería y partiendo de la modelación de procesos físicos del ciclo hidrológico, se ha logrado describir al menos en parte la complejidad de los fenómenos que ocurren en la naturaleza, como lo es la simulación del crecimiento de los cultivos, en este caso específico del maíz. Debido a la importante producción anual de maíz que produce el Distrito de Riego 063 Guasave, Sinaloa y a las significativas pérdidas de cultivo de maíz sufridas a causa de las bajas temperaturas registradas en febrero de 2011 se decidió realizar la presente investigación que comprende la estimación de los rendimientos de maíz en la resiembra del mes de...

Palavras-chave: Modelo de simulación; Maíz; Distrito de Riego 063; Rendimiento potencial; Requerimiento hídrico; Simulation model; Corn; 063 Irrigation District; Yield potential; Water requirement; Hidrociencias; Maestría.

Ano: 2012

URL: http://hdl.handle.net/10521/964

Scenarios are Plausible Stories about the Future, not Forecasts

Schneider, Richard R.; Ministik Environmental Consulting; contact@borealcentre.ca; Boutin, Stan; Department of Biological Sciences, University of Alberta; Stan.Boutin@ualberta.ca; Stelfox, J. Brad; Forem Technologies; bstelfox@telusplanet.net; Wasel, Shawn; Alberta-Pacific Forest Industries Inc.; waselsh@alpac.ca.

Tipo: Peer-Reviewed Response

Palavras-chave: Alberta; Boreal forest; Cumulative industrial impacts; Forestry industry; Integrated resource management; Petroleum industry; Simulation model; Western Canadian Sedimentary Basin.

Ano: 2007

The Effect of Protection and Exchange Rate Policies on Agricultural Trade: Implications for Argentina, Brazil, and Mexico

Krissoff, Barry; Ballenger, Nicole.

The impacts of reducing both agricultural and nonagricultural protection on the agricultural sector are assessed with emphasis placed on Argentina, Brazil, and Mexico. By modeling simultaneously all goods sectors of the economy in a multi-country framework, we evaluate the importance of (1) the relative rates of protection between sectors and (2) exchange rate adjustments that follow trade liberalization in a world of floating rates. We find substantial improvements in net agricultural trade for Argentina and Brazil, particularly following a multilateral trade and exchange rate liberalization. Additionally, the value of gross domestic product improves for all three countries following multilateral liberalization suggesting that these countries experience...

The Export Enhancement Program: Prospects Under the Food, Agriculture, Conservation, and Trade Act of 1990

Palavras-chave: Trade liberalization; Protection; Exchange rates; Simulation model; Argentina. Brazil; Mexico; International Relations/Trade.

Ano: 1987

URL: http://purl.umn.edu/51820

Haley, Stephen L..

According to provisions of the 1990 U.S. farm bill, the export enhancement program (EEP) will continue to be an important instrument in promoting U.S. agricultural exports and in challenging subsidizing competitors, like the European Community (EC), with funding levels set at a minimum of $500 million annually through 1995. This research, whose purpose is to evaluate the likely effectiveness of the wheat EEP through 1995, reaches several conclusions: (1) the EEP will have a significant effect on U.S. wheat exports, but will be subject to diminishing returns at levels higher than the annual minimums; and (2) the EC will only be marginally affected by the EEP, that is, it can effectively counter the effects of the EEP at low cost.

The key importance of the underlying stock-recruitment assumption when evaluating the potential of management regulations of Atlantic bluefin tuna

Palavras-chave: Export subsidies; Export enhancement program; Agricultural trade; Simulation model; Wheat; Coarse grains; Agricultural and Food Policy; International Relations/Trade.

Ano: 1991

URL: http://purl.umn.edu/51142