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PD/A CRSP Research Reports 94-76 to 95-80

PD/A CRSP Research Reports 94-76 to 95-80

Comparison of two techniques for determining community respiration in tropical fish ponds

David Teichert-Coddington and Bartholomew Green, Department of Fisheries and Allied Aquaculture and Alabama Agricultural Experiment Station, Auburn University, Alabama 36849, USA

1 December 1994, CRSP Research Report 94-76

Abstract Two techniques for determining community respiration in organically fertilized tilapia grow-out ponds were compared: (1) whole pond respiration (WPR) from changes in nocturnal dissolved oxygen concentrations corrected for diffusion, and (2) the sum of water column (WCR), benthic (BR), and fish respiration (FR), components of community respiration. Mean WPR (0.568 g O2 m-2 h-1) was significantly higher (P<0.01) than mean sum of community respiration components (0.401 g O2 m-2 h-1). Mean WCR, BR, and FR were 0.319, 0.068, and 0.015 g O2 m-2 h-1, respectively. Indirect determinations of community components by difference of WPR and the sum of the other two components will be significantly higher than in situ determinations.

This abstract was excerpted from the original paper, which was published in Aquaculture 114:41-50, 1993.


Tilapia yield improvement through maintenance of minimal oxygen concentrations in experimental grow-out ponds in Honduras

David Teichert-Coddington and Bartholomew W. Green, Department of Fisheries and Allied Aquaculture and Alabama Agricultural Experiment Station, Auburn University, Alabama 36849-5419, USA

1 December 1994, CRSP Research Report 94-77

Abstract Tilapia yields and water quality were compared in 1000-m2 grow-out ponds that were unaerated, or aerated beginning at 10 or 30% of oxygen saturation. Tilapia yield and individual final size were significantly greater in aerated ponds than in unaerated ponds, but there were no significant differences between levels of aeration. Treatment means of organic-N, total P, chlorophyll a, net primary productivity, and total volatile solids were not significantly different. However, aeration caused higher clay turbidity as indicated by significantly higher total fixed solids and lower Secchi disk visibility in aerated treatments. Maintenance of oxygen above minimal levels augmented tilapia yields, but additional research is needed to make aerator use in tilapia culture more efficient and profitable.

This abstract was excerpted from the original paper, which was published in Aquaculture 118:63-71, 1993.


Seepage reduction in tropical fish ponds using chicken litter

D.R. Teichert-Coddington and R.P. Phelps, Department of Fisheries and Allied Aquaculture and Alabama Agricultural Experiment Station, Auburn University, Auburn, Alabama 36849, USA

M. Peralta, Gualaca Freshwater Aquaculture Research Station, Dirección Nacional de Acuicultura and, Instituto De Investigaciones Agro-pecuaria, Gualaca, Panama

1 December 1994, CRSP Research Report 94-78

Abstract The effect on seepage of adding chicken litter at the rate of 125, 250, 500 and 1000 kg ha-1 wk-1 total solids (TS) for 5 months to earthen fish ponds in Panama was measured. Each treatment was replicated 3 times. Application of litter at all rates reduced seepage. Before litter application, mean seepage for all ponds ranged from 27 to 37 mm day-1; after application, mean seepage ranged from 8 to 17 mm day-1. This represented a seepage reduction of 54-76%. Linear regression of mean seepage reduction on rate of chicken litter was significantly positive (P<0.01). Reduction of seepage was most rapid for ponds receiving the highest rate of chicken litter. Near maximum reduction occurred during the first month within the three highest application rates. The lowest rate resulted in a linear reduction of seepage with time. A limit was reached at all application rates where additional litter application did not result in greater seepage reduction. Litter applications of at least 250 kg ha-1 wk-1 TS for a month are recommended for rapid seepage reduction in ponds. Draining and drying the ponds following 5 months of litter application did not appreciably increase seepage.

This abstract was excerpted from the original paper, which was published in Aquacultural Engineering 8:147-154, 1989.


Modeling photosynthetic production optimization for aquaculture ponds

Philip Giovannini and Raul H. Piedrahita, Department of Biological and Agricultural Engineering, University of California, Davis, California, USA

27 February 1995, CRSP Research Report 95-79

Abstract In an aquaculture pond, the primary production system serves both as the basis for the natural food chain, and as a primary source of dissolved oxygen (DO). As the productivity of the pond system and the standing crop of phytoplankton increases, so does the degree of fluctuation in diel DO concentrations, water quality, and the degree of vertical stratifications of the water column. In highly turbid pond systems the rapid extinction of incident light in the surface layers results in benthic zones serving only as a net oxygen sinks, even while the surface is exposed to full sunlight and is a net oxygen source. As the standing phytoplankton crop is reduced, self shading decreases, as does total food availability and gross production of oxygen, but the stability of the system, in terms of DO fluctuations and water quality, increases. Therefore, in this respect, the trade-off in balancing the pond system is in terms of gross productive potential versus water-quality stability.

This abstract was excerpted from the original paper, which was published in Aquacultural Engineering 13:83-100, 1994.


Model for predicting dissolved oxygen levels in stratified ponds using reduced data inputs

Steven D. Culberson and Raul H. Piedrahita, Department of Biological and Agricultural Engineering, University of California, Davis, California, USA

27 February 1995, CRSP Research Report 95-80

Abstract Previous attempts at the prediction of dissolved oxygen (D.O.) levels in ponds used for aquaculture have often relied on the assumption of homogeneous pond water quality over the water column depth. Using a previously-reported stratified temperature model as a basis for structure, the authors have modified a mass-balance model for the prediction of dissolved oxygen levels in shallow aquaculture ponds. The model has been updated with recent information concerning the behavior of pond phytoplankton throughout the diurnal cycle, rendering accurate predictions of D.O. levels in both stratified and fully-mixed ponds. In addition, the overall data inputs required by the model have been significantly reduced from those required by previous models. Simulations for sites in Northern California are presented, as well as for several sites located in various places around the globe, using the Pond Dynamics/Aquaculture Collaborative Research Support Program Database for input data. The strategies used for dealing with reduced data sets, and the associated assumptions made, are also presented.

This abstract was excerpted from the original paper, which was published as pages 543-552 in Techniques for Modern Aquaculture, Proceedings of an Aquacultural Engineering Conference, Jaw-Kai Wang (Editor), 1993. American Society of Agricultral Engineers, St. Joseph, Michigan.


Previous group of reports: 94-71 to 94-75 Next group of reports: 95-81 to 95-85

To full list of PD/A CRSP Research Reports