4 présentations

• 
  08h30 - 09h00

  Optimizing stocking and harvesting strategy for aquaculture

  • Yajie Liu,
  • Thi Thanh Thuy Pham, prés., University of Tromsø

  This paper is about to examine the optimal management strategy of salmon aquaculture by incorporating a sequential stocking and harvesting schedule. The focus of the paper is on the salmon grow-out stage – the rearing and feeding of salmon smolt in sea cages to market size. The salmon production is determined by the growth of salmon which is defined by varying biophysical factors such as seasonal changes (e.g., temperature), operational decision (e.g., delousing) and feeding while the profitability is affected by variables associated with production cost, management strategies and market price. By taking into account these dimensions, i.e., fish physiology and economics of production, we develop a bioeconomic model to analyse a sequential stocking and harvesting schedule. Dynamic programming is used to determine the stocking and harvesting strategies to maximize the overall productivity and profitability of the salmon grow-out stage. The preliminary result indicates that a sequential stocking and harvesting schedule generate a higher total profit than a single stocking and harvesting schedule, but dependent on stocking and harvesting strategies.

• 
  09h00 - 09h30

  Estimating the economic damages of United States invasive forest pests

  • Emma J. Hudgins, prés., McGill University
  • Frank H. Koch, United States Forest Service, Southern Research Station
  • Mark Ambrose, North Carolina State University, Raleigh, NC
  • Brian Leung, McGill University

  Urban trees are the main target of economic damages due to invasive forest pests in the United States. Existing damage estimates due to pest species are highly cited (263 citations) and used in policy recommendations (ISPM15), but are currently out of date. We combined three existing frameworks to more accurately estimate future damages to US urban trees due to invasive forest pests by building off of an existing economic approach to estimate pest damages (Aukema et al. 2011), a recent modelling framework for US urban tree distributions (Koch et al. 2018), as well as forecasts of all-species forest pest spread.

• 
  09h30 - 10h00

  Viability of agro-ecological systems under climatic uncertainty

  • Aichouche Oubraham, prés., GERAD
  • Georges Zaccour, Chair in Game Theory and Management, GERAD and HEC Montréal
  • Patrick Saint-Pierre, LASTRE, IRD & LEDA-SDFi

  In order to cope with the post-war demographic boom and ensure food security, agronomic systems drastically changed and migrated to agricultural practices based on chemical fertilization of soil and intensive and specialized farming practices. This has increased soil productivity in the short term, but in the long term have caused serious ecological drawbacks (soil degradation, pollution, loss of biodiversity, erosion, etc.) and even reversed the trend of the agricultural productivity. It is therefore necessary to think about some ways to limit these damages while ensuring an acceptable agricultural yield.
  In this work we rely on the mathematical viability theory to study the sustainability of agricultural systems subject to climate uncertainty. Our objective is to determine farming practices and activity sequences that allow to restore soil quality to a desired level while ensuring an acceptable level of productivity in the presence of risk of major climatic disasters.

• 
  10h00 - 10h30

  Stochastic and stratified dispersal and their effect on predicting invasive pest populations: a case of Emerald Ash Borer (EAB) in New Jersey

  • Erik Lyttek, prés., Montclair State University
  • Pankaj Lal, Montclair State University
  • Eric Forgoston, Montclair State University

  The advent of globalized trade has led to the introduction invasive pests and diseases. The dispersal rate of pests and disease has an intrinsic impact on the intensity of these disturbances. Many pests exhibit irregular spread due not only to unknown biological factors, but also due to anthropogenic transport. EAB is an Asiatic pest that has been spreading across the United States since the late 1990s and has since eliminated approximately 85 million ash trees. We propose a stochastic spread and consumption model to address the issue. The goal is the capture of spread caused by natural and anthropogenic means.