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PD/A CRSP Research Reports 95-86 to 96-90

PD/A CRSP Research Reports 95-86 to 96-90

Evaluation of soil pH-Percent base saturation relationships for use in estimating the lime requirements of earthen aquaculture ponds

James R. Bowman and James E. Lannan, Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR. 97331-3803 USA

25 July 1995, CRSP Research Report 95-86

Abstract The pH-percent base saturation relationships of selected subsurface soil horizons were evaluated by fitting theoretical and empirical models to published soils data. The selected models were validated by fitting them to an independent set of data. The selected models did not fit the second set of data as well as the original data, but they provide initial approximations for use in cases when real values can't be measured. Possible reasons for the poorer fit to the second data set are discussed. One possibility for increasing the range of soils to which suitable pH-percent base saturation models can be fit is to refine the soil classification system being used. Valid pH-percent base saturation models can be combined with on-site soil pH measurements and typical cation exchange capacity values to estimate aquaculture pond lime requirements on a broad range of soil types in the field i.e., without reliance on laboratory analyses.

This abstract was excerpted from the original paper, which was published in Journal of the World Aquaculture Society 26:172-182, 1995. pp.172-182.


Water budgets for fish ponds in the dry tropics

Bartholonew W. Green and Claude E. Boyd, Department of Fisheries and Allied Aquacultures, Auburn University, Auburn, AL 36849-5419

8 January 1996, CRSP Research Report 96-87

Abstract Water budgets were calculated for embankment fish ponds located in the dry tropics. Two 5-month studies were conducted at Comayagua, Honduras. Daily pond evaporation averaged 0.55 ± 0.22 and 0.64 ± 0.17 cm during studies 1 and 2, respectively. Pond evaporation was 14.5% greater during study 2. Significantly greater pond evaporation was measured during the 3 driest months compared to the 3 rainiest months. Mean daily seepage ranged from 0.11 to 0.43 cm and from 0.06 to 0.60 cm during studies 1 and 2, respectively. Total rainfall during study 1 exceeded that during study 2 by 43%. Regulated inflow water was required every month to replace water losses to pond evaporation and seepage. Pond evaporation accounted for 70% of total water loss during both studies, while seepage accounted for the remaining water loss. Rain accounted for 45.5 and 21.8% of gains during studies 1 and 2 respectively. Regulated inflow water accounted for 52.8 and 77.9% of the respective gains.

This abstract was excerpted from the original paper which was published in Aquacultureal Engineering 14(4)1995:347-356


Chemical budgets for organically fertilized fish ponds in the dry tropics

Bartholomew W. Green and Claude E. Boyd, Department of Fisheries & Allied Aquacultures, Auburn University, AL 36849-5419 USA

8 January 1996, CRSP Research Report 96-88

Abstract Chemical budgets were determined for nitrogen, phosphorus, dissolved oxygen and chemical oxygen demand for three 0.1-ha earthen pounds stocked with Oreochromis niloticus at the El Carao National Fish Culture Research Center, Comayagua, Honduras, for two 150-d culture periods, corresponding to the rainy and dry seasons. Layer chicken litter was added to ponds weekly at 500 kg dry matter/ha. Concentrations of nitrogen, phosphorus, and chemical oxygen demand (COD) in pond water increased during each season. No significant seasonal differences in concentrations of water quality variables were observed. Chicken litter added to ponds represented 92-94% of N input, 93-95% of P input, and 43-52% of COD input. Photosynthesis by phytoplankton provided 47-56% of COD and 98% of dissolved oxygen (DO) added to ponds. Net inward diffusion of oxygen added 1.2-1.5% of total DO. Regulated inflow was a minor source of nutrients, and contributed 3-4% of input N, 3-4% of input P, 1% of COD input, and 1% of DO input. Nutrient inputs from rain were < 1% of total for each nutrient. Fish harvest accounted for 18-21% of total N, 16-18% of total P and 2% of COD added to ponds. Community respiration accounted for 48-57% of COD and 99.5% of DO added to ponds. Nutrient losses in pond effluent at draining were: 7-9% of total N, 29-37% of total P and 2-3% of COD. While measured gains exceeded measured losses, significantly greater N, P and organic matter concentrations in pre-drain samples indicated pond mud was a major sink for added nutrients; accumulation in mud represented 70% of total N, 35-40% of total P, and 38-46% of COD.

This abstract was excerpted from the original paper, which was published in Journal of the World Aquaculture Society 26(3)1995:284-296


Semi-intensive commercial grow-out of Penaeus vannamei fed diets containing differing levels of crude protein during wet and dry seasons in Honduras

David R. Teichert-Coddington, Department of Fisheries and Allied Aquacultures, Alabama Agricultural Experiment Station, Auburn University, AL 36849 USA

Rigoberto Rodriguez, Granjas Marinas de San Bernardo, S.A., Choluteca, Honduras

8 January 1996, CRSP Research Report 96-89

Abstract Shrimp were grown under ideal management conditions during two distinct seasons of the year at stocking densities used most often in Honduras with the objective of evaluating the usefulness of high protein diets. A randomized design in 2 x 2 factorial arrangement was used to test a diet composed of either 20 or 40% crude protein in earthen ponds that were stocked with juvenile Penaeus vannamei at 5 to 11/m2. The study was repeated during wet and dry seasons. Dietary protein level had no significant effect (P>0.05) on survival, yield, or average weight of shrimp at either density during both seasons. Mean shrimp weight in high density ponds was significantly lower than mean shrimp weight in low density ponds during the wet season, but there was no significant weight difference because of stocking rate during the dry season. Mean survival was significantly lower at the higher stocking rate during the dry season. Net income was negative during the dry season, particularly at the high stocking density. Mean production was 240% greater in the wet season than the dry season. Diets offered P. vannamei stocked at 5 to 11/m2 should contain no more than 20% protein, regardless of season. Higher dietary protein levels increase cost and waste nitrogen resulting in greater shrimp yields. The high stocking density might increase profitability in the wet season, but long term sustainable production may be more feasible at lower stocking creates because of reduced nutrient wastes.

This abstract was excerpted from the original paper, which was published in the Journal of the World Aquaculture Society 26(1)1995:72-79


Dry matter, ash, and elemental composition of pond-cultured Penaeus vaannamei and P. stylirostris

Claude E. Boyd and David Teichert-Coddington, Department of Fisheries and Allied Aquacultures, Alabama Agricultural Experiment Station, Auburn University, AL 36849 USA

9 January 1996, CRSP Research Report 96-90

Abstract Mass balance calculations for nutrient elements are useful in determining the efficiency of fertilizers and feeds in aquaculture ponds, for studying the fate of nutrients within pond ecosystems, and for estimating the pollution potential of pond effluents. In research, mass balance computations may be site specific and require complete data on all nutrient inputs and outputs for a particular pond. For general assessments of nutrient mass balance, fewer data are necessary. For example, the potential nitrogen and phosphorus loadings of intensive aquaculture ponds can be estimated from the stocking density, feeding rate, expected feed conversion ratio, and nitrogen and phosphorus concetrations in feed and aquaculture product. Most of the nessary information is easily obtained, but data on whole body elemental composition of aquaculture species are scarce.

The present study was conducted to assess the elemetal composition of two species of shrimp (Penaeus vannamei and P. stylirostris) that are widely cultured in coastal regions of tropical and subtropical North and South America. Elements of primary concern for pond management and environmental impact considerations are carbon, nitrogen, and phosphorus, but analyses included several other nutrients.

This abstract was excerpted from the original paper, which was published in Journal of the World Aquaculture Society 26(1)1995:88-92


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