|Ward, George - CRWR,U TEXAS,AUSTIN|
Submitted to: International Aquaculture Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 3, 2004
Publication Date: August 25, 2004
Citation: Green, B.W., Ward, G.H. 2004. Predicting changes in the assimilative capacity of the El Pedregal and San Bernardo estuaries, Honduras, using the ESTERO model. In: VII Central American Aquaculture Symposium, August 25-28, 2004, Tegucigalpa, Honduras. p. 55. Interpretive Summary: Not required.
Technical Abstract: Between 1994-2001, we conducted an intensive data collection and modeling study of two channel estuaries (El Pedregal and San Bernardo) in the shrimp aquaculture region of Honduras that drain into the Gulf of Fonseca. A transport model for estuarine salinity and dissolved oxygen (DO) was applied to predict the tidal-mean, section-mean concentrations of salinity and DO. The model, named ESTERO, was validated for the prediction of salinity and dissolved oxygen, and now provides the capability to explore further the interaction between shrimp farm development and estuary assimilative capacity. Results from model runs based on shrimp farm operations in 2000 indicate that the DO concentrations in the main channel of each estuary system are low by estuary standards, being less than 3 mg/L throughout most of their length in both seasons, and often approaching zero in certain stretches of each estuary during the dry season. While shrimp farm effluents contribute to the decreased DO concentrations observed in both estuaries, model runs where the shrimp farm load was reduced incrementally down to zero showed that the quality of each estuary was strongly influenced (and under certain conditions dominated) by poor DO in the upstream reaches and the influx of higher DO from Monypenny Bay. Concentrations of DO in the San Bernardo channel were about 5 mg/L in 1995 data set, but declined to less than 3 mg/L in 2000 data set; this change is considered the direct result of the diversion of the Río Negro channel to Nicaragua as a result of Huracán Mitch. The ESTERO user interface will be described and demonstrated, and various scenarios of levels of shrimp farm development along the El Pedregal and San Bernardo estuarine systems will be evaluated for their effect on estuarine assimilative capacity.