Background
Objectives
Significance
Anticipated Benefits
Beneficiaries
Methods
Deliverables
Schedule

Background

In the past, most pond modeling efforts have been viewed as a means of describing the dynamics of the pond ecosystem, and the use of systems models in a decision making context has received limited attention. Besides, the complexity of pond ecosystems often precludes field experimentation of several management options simultaneously. Thus, managers, planners, extension agents and researchers often do not have access to tools that can allow them to better understand biological and physico-chemical processes in ponds, resulting in suboptimal use of resources and the discharge of nutrient-rich effluents from pond facilities. In either case, the economic viability and sustainability of the facility is compromised. In POND^©, simulation of pond processes is accomplished by assembling a facility and accessing various domain-specific 'experts' (Ernst et al., 1993; Bolte et al., 1995; Fig. 1). Although these 'experts' provide some capabilities for decision support in the current version of POND^©, their ability to interactively control simulation runs and optimize management strategies is limited.

Objectives

1) To integrate models of pond dynamics (including previous work, and models resulting from Studies One and Two above) into a format that can be used to conduct numerical experiments and optimize pond management scenarios,

2) To enhance the decision support capabilities of the 'experts' available within POND^©,

3) To conduct sensitivity analyses for different POND^© models, and

4) To use modeling and decision support capabilities in POND^© as the basis for developing pond management guidelines.

Significance

Improved modeling and decision support capabilities in POND^© will allow users to examine the effects of a variety of management practices on pond performance, and ultimately on the economics, potential environment impacts and sustainability of the pond facility, all of which had been identified as constraints in the PD/A CRSP Continuation Plan 1996-2001. Numerical experiments will also allow the simulation of pond management scenarios that would be difficult to conduct in the field.

Anticipated Benefits

Improved decision support tools for optimizing pond facility operations leading to more efficient and sustainable farming practices.

Beneficiaries

Aquaculture managers, extension agents, planners, educators and researchers.

Methods

POND^© will essentially serve as an experimental test for analyzing management strategies. This will involve modifications to the software architecture and the user-interface to accommodate management operations such as scheduling issues (e.g., partial stocking/harvesting, market references), polyculture (e.g., species/lot combinations, stocking densities, effects on pond environment), fertilization and feeds (application issues, effects on water and soil characteristics), and management intensity. Sensitivity analyses will be also be conducted to determine the importance of various parameters in the POND^© models. The overall emphasis will be on analyzing resource use and identifying management strategies that minimize operating costs while maintaining low levels of organic and inorganic pollutants in discharged effluents. Tools (i.e., genetic algorithms; Michalewicz, 1992) already available in POND^© for automatic model parameterization will be used for management optimization. The results of such analyses will be used to develop and implement decision support algorithms in POND^© 'experts', and contribute to pond management guidelines developed by the overall CRSP.

Deliverables

Capabilities for optimizing pond facilities within the POND^© framework; a report summarizing optimization results under various management practices.

Schedule

1/1/97 to 4/30/98 (see also Table 1).

Report Submittal: 4/30/98