In addition to specific research activities implemented at in-country sites in Central and South America, Africa, and Asia, the Ninth Work Plan includes activities that address cross-cutting themes which have more immediate, wider application than those from prime and companion site investigations. This research builds upon and expands information from earlier PD/A CRSP research. Work plans are presented for six research themes of cross-cutting research: Pond Dynamics; Reproduction Control; Aquaculture Systems Modeling; Effluents and Pollution; Marketing and Economic Analysis; and Decision Support Systems. Additional research themes—Feeds and Fertilizers; New Aquaculture Systems/New Species; Appropriate Technology; and Adoption/Diffusion—are addressed in regional research.

The dynamic interactions among nutrients and fish yield continue to be a major focus of the CRSP. The influence of pond sediments on pond dynamics will be addressed in proposed research. Pond soil samples from the PD/A CRSP sites will be characterized and related to the role in the cycling of chemicals used in aquaculture, including those that might impact the environment through effluents. This relates to chemicals such as steroids that are used in hatchery operations such as monosexing for reproductive control. Alternative methodologies to feeding hormones, such as immersion for more abbreviated periods of exposure, may reduce the overall amount of steroids used and thus released. Non-steroid techniques using chromosome manipulation might provide reproduction control without chemical use and thereby reduce the environmental impact. Also, chromosome manipulation can be used in conjunction with sex reversal to produce broodstock for monosex breeding programs, but for both of these applications, assumptions of the genetic basis of sex determination must be tested and verified.

The proposed work on aquaculture systems modeling will update a previously developed model that uses stochastic weather inputs. The updated model will be used to generate probability distributions for pond water quality and fish yields. Previous models developed under the PD/A CRSP have been programmed using a commercially available modeling language. While this strategy has simplified and speeded up the model development process, the resultant models are not particularly user-friendly and require special software to execute. The updated model to be developed under the Ninth Work Plan will be coded using conventional programming languages to produce a user-friendly, stand-alone application.

Social scientists’ involvement in PD/A CRSP has increased over time, primarily studying localized issues. A broader approach will be used in the Ninth Work Plan by initiating studies to develop local tilapia markets and by developing a technique that can assist researchers to screen possible technologies for pond trials. Work will continue on the development of estimates of economic returns to the research investment of the PD/A CRSP. A beneficial aspect of these activities will be increased interaction among economists and site personnel.

Aquaculture managers are confronted with complex decisions for culture facilities, effects on the environment, and the role in larger farming systems. Analytical tools for decision support systems integrate knowledge from mathematical models, expert systems, and databases into software systems. CRSP researchers developed POND©, a software package that provides capabilities for simulation modeling and economic analyses of pond facilities. The software is based on fundamental principles of pond aquaculture. Several areas of improvement are being undertaken under the Ninth Work Plan, focusing on 1) improving the utility of POND© for education and extension purposes, 2) enhancing POND©s underlying models in the areas of pond sediment-water column interactions, 3) calibrating and validating POND© for additional culture organisms, particularly various shrimp species, and 4) enhancing POND©s ability to address scheduling and other applied pond management issues. These improvements should improve the usefulness of the software in addressing the needs of both educators and pond managers, and allow improved decision-making in areas related to fertilization, feeding, stocking, water use and effluent discharge, and economic optimization.