Note: Schedule has been revised. See First Addendum to the Eighth Work Plan

Objectives
Significance
Anticipated Benefits
Beneficiaries
Experimental Design
Identification of Deliverables
Schedule
References

Objectives

1) Monitor water quality of major estuaries affected by shrimp farming to detect trends toward quality deterioration or improvement; and

2) Formulate and validate numerical estuary models to predict future estuarine water quality conditions under various scenarios, and estimate carrying capacity of estuaries based on water quality, farm chemical budgets and estuarine fluid dynamics.

Significance

This research focuses on environmental effects of aquaculture, particularly the impact of pond effluents on receiving waters and how the assimilation capacities of the receiving waters are affected. An increased understanding of these impacts can lead to formulation of management practices and/or policy to minimize any negative environmental impact of aquacultural effluents. A baseline of water quality has been established for the major estuaries supporting the shrimp culture industry in southern Honduras. Correlation between industry farm management and estuarine water quality can now be drawn by continued time-series measurements. Models will serve both a diagnostic purpose, in assisting the interpretation of the results of the estuarine sampling program and a prognostic purpose, in acting as a tool for predicting the estuary responses to shrimp farm operations.

Anticipated Benefits

The formulation of models using water quality and estuarine dynamics data for predicting carrying capacity of estuaries will be of incalculable benefit to the shrimp industry and Honduran government agencies charged with land use planning and environmental regulation. Environmental management of estuarine systems and regional land use planning cannot be accurately accomplished without the models, because reasonable estimations of carrying capacity would be impossible. The Honduran government has in fact stopped further shrimp farm development until an objective determination of carrying capacity has been achieved for the various estuaries. The program of data collection and carrying capacity estimation implemented by the CRSP can be used as a model by other countries in the region with similar issues to resolve.

Beneficiaries

Ministry of the Environment and Ministry of Natural Resources, Government of Honduras; Honduran shrimp industry; other countries with similar aquacultural/environmental issues to resolve.

Experimental Design

1) Water quality monitoring will be a continuation of the program initiated in 1993 by the Aquaculture CRSP (Teichert-Coddington, 1995). Shrimp producers located throughout the Gulf of Fonseca will transport estuarine water samples on ice to the laboratory on a bi-weekly basis to be analyzed. The samples will have been collected from the outfall of water supply pumps at high tide no more than 6 hours before being transported to the lab. Samples will be analyzed for phosphorus, nitrogen, total alkalinity, chlorophyll-a, BOD, and salinity according to methods prescribed for salt water analyses by Parsons et al. (1992), and Grasshoff et al. (1983).

2) At least two estuary models will be employed with sampling data (Ward and Montague, 1995). First, to treat the hydraulic behavior of the estuaries, which is dominated by the high tidal range and by the seasonal variation in inflow, a hydrodynamic model will be applied. This is a numerical solution to the full time-varying section-mean equations of momentum and continuity, including provision for flooding and de-watering of adjacent tidal flats. Second, to treat the water quality of the estuaries, a combined model of transport and kinetics will be used, including inputs for the various organic loads, both from shrimp farms and from other sources, and specific formulations of kinetic interconversions.

In addition to using estuarine sampling data in the estuary models, time-series and graphical analyses will be used to compile and organize the estuarine monitoring data.

Identification of Deliverables

Models for projecting future water quality based on different scenarios of shrimp production and nutrient discharge.

Schedule

Estuarine sampling, 8/96 - 4/98; estuarine model development and analyses, 1/97 - 6/97.

Final Report Submittal: 9/97

References

Grasshoff, K., Ehrhardt, M. and Kremling, K. 1983. Methods of seawater analysis. Verlag Chemie, Germany, 419 pp.

Parsons, T. R., Maita, Y. and Lalli, C. M. 1992. A manual of chemical and biological methods for seawater analysis. Pergamon Press, New York, NY, U.S.A., 173 pp.

Teichert-Coddington, D. R. 1995. Estuarine water quality and sustainable shrimp culture in Honduras. In: S. Hopkins and C. Browdy (Eds.), Proceedings of the Special Session on Shrimp Farming, Aquaculture '95, San Diego, CA, U.S.A., World Aquaculture Society, Baton Rouge, LA, U.S.A., pp. 144-155.

Ward, G. H. and Montague, C. L. (1995). Estuaries. Handbook of water resources Ed. L. W. Mays. New York, McGraw-Hill. In press.