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PD/A CRSP Aquanews-Fall 2000
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Notices of Publication

These Notices of Publication announce recently published work carried out under PD/A CRSP sponsorship. To receive a full copy of a report, please contact the author(s) directly unless it is otherwise noted.

CRSP Research Report 00-150

Effects of shrimp farming on the hydrography and water quality of El Pedregal and San Bernardo estuaries, Gulf of Fonseca, Honduras*

George H. Ward, Jr.
Center for Research in Water Resources
The University of Texas at Austin
Austin, TX 78712 USA

Intensive data collection and a modeling study have been underway for the past several years addressing two of the channel estuaries draining into the Gulf of Fonseca, Estero El Pedregal and Estero San Bernardo. Data have been compiled on the shrimp farm configurations, exchange rates, and effluent chemistry. Temperature, salinity, and dissolved oxygen profiles have been measured in the estuary channels during both rainy and dry seasons. Physiographic, hydrographic, and meteorological data have been obtained to supplement the estuary data. This report examines the assimilative capacity of these estuaries with respect to dissolved oxygen (DO). The oxygen demand of organics is measured by biochemical oxygen demand (BOD). Shrimp farm BOD loadings were estimated from effluent data and exchange. A transport model for salinity and DO in the estuaries was applied to predict the tidal-mean and section-mean concentrations of salinity and DO. The model predictions of DO—based on 1995 BOD loadings—were satisfactory. Future loadings based upon full shrimp farm development along these two estuaries were then input to determine the resulting DO under these conditions. It was found that the 1995 configuration is already pressing the carrying capacity of both systems, and the DO will be worse at full development. Shrimp farms placed farther upstream than about 20 km from the mouth will most likely have excessive impact on the DO in the estuary, which is exacerbated under dry-season conditions. Negative impacts of a specific farm can be ameliorated by reducing or eliminating pond discharges during the dry season and by reducing the level of water exchange employed. This work needs to be extended to address additional water quality parameters and to incorporate larger spatial scales, especially to establish the interaction between different estuaries draining into Fonseca.

*To order this publication, contact:
Publications/Information Management
PD/A CRSP
Oregon State University
418 Snell Hall
Corvallis, OR 97331-1643 USA


CRSP Research Report 00-151

Chemical and physical properties of shrimp pond bottom soils in Ecuador

Stanislaus Sonnenholzner
Fundación Centro Nacional de Acuicultura e Investigaciones Marinas
P.O. Box 09-01-4519
Guayaquil, Ecuador

Claude E. Boyd
Department of Fisheries and Allied Aquacultures
Auburn University
Auburn, AL 36849 USA

Chemical and physical analyses were conducted on bottom soil samples from 74 brackish-water ponds representing 40 shrimp farms in Ecuador. Most ponds had soils with pH > 6 and total carbon concentrations < 2.5%. Carbon was mostly in organic form, for the average concentration of carbonate carbon was 0.06%. The C : N ratio was 8 to 10 in soils with < 2.5% carbon. In ponds built in former mangrove areas, soil carbon was > 2.5% and C : N ratios were 25 to 30. Ponds soils in former mangrove areas also tended to be high in total sulfur and low in pH. Lack of correlation between carbon and sulfur in mangrove soils suggested that most of the sulfur was inorganic and presumably in sulfides. Soils containing above 0.4% free carbonate (as equivalent CaCO3) had pH values > 7. Although carbonate concentration was a major factor controlling soil pH, calcium hardness of pond waters was strongly influenced by salinity (and calcium) in the water supply. Total phosphorus concentrations averaged 898 mg/kg, and dilute acid extractable phosphorus usually accounted for 25–35% of the total. Concentrations of major cations and minor elements varied greatly in soils and exhibited ranges of up to three orders of magnitude. Contrary to opinions of shrimp producers, many pond soils in Ecuador are not acidic and few soils have a high organic matter content. Proper use of soil and water testing could greatly improve the efficiency of liming and other soil management practices.

This abstract was excerpted from the original paper, which was published in the Journal of the World Aquaculture Society, 31(3):358–375.


CRSP Research Report 00-152

Vertical gradients of organic matter concentration and respiration rate in pond bottom soils

Stanislaus Sonnenholzner
Fundación Centro Nacional de Acuicultura e Investigaciones Marinas
P.O. Box 09-01-4519
Guayaquil, Ecuador

Claude E. Boyd
Department of Fisheries and Allied Aquacultures
Auburn University
Auburn, AL 36849 USA

Total carbon concentration and respiration rate were greater in the upper 0.5-cm or 1.0-cm layers of pond soil than in deeper layers. The respiration rate expressed on either a dry soil weight basis or a soil carbon basis decreased with increasing soil depth. This suggests that the ratio of labile to refractory organic matter also declines with increasing soil depth. Variation in soil properties with depth should be considered in pond bottom soil sampling programs.

This abstract was excerpted from the original paper, which was published in the Journal of the World Aquaculture Society, 31(3):376–380.


CRSP Research Report 00-153

Development of decision support tools for aquaculture: The POND experience

John Bolte
Department of Bioresource Engineering
Oregon State University
Corvallis, OR 97331 USA

Shree Nath
Skillings–Connolly, Inc.
5016 Lacy Boulevard S.E.
Lacey, WA 95803 USA

Doug Ernst
Department of Bioresource Engineering
Oregon State University
Corvallis, OR 97331 USA

Decision support systems (DSS) are potentially valuable tools for assessing the economic and ecological impacts of alternative decisions on aquaculture production. In this paper, we discuss the philosophy of design, functional modules and application areas of POND, a decision tool that has been developed to allow analysis of pond aquaculture facilities by the use of a combination of simulation models and enterprise budgeting. We focus less on the details of POND’s internal models, and more on the experiences we have gained from going through the process of the designing, developing and using the POND software. POND was designed and implemented using object-oriented programming principles. The software makes use of a simulation framework to provide much of the generic simulation, data handling, time flow synchronization and communication features necessary for complex model-based DSSs. Additionally, an architecture suitable for representing and manipulating pond aquaculture facilities was developed in order to meet the design specifications of POND. This architecture includes a series of mini-databases, a number of knowledge-based components (‘experts’), models of the pond ecosystem, and various decision support features (e.g. assembling alternate management scenarios, economic analysis, and data visualization). A typical POND simulation consists of assembling a number of appropriate objects or entities (e.g. multiple ponds and fish lots), their management settings together with appropriate experts (e.g. an aquaculture engineer, an aquatic biologist, an economist, etc.), and projecting changes in the facility over time. Our experience with the development of POND and other simulation-based tools indicates that the object-based approach provides a robust foundation for developing tools which allow code reusability, facilitate maintenance of complex software, and enable partition of program development among multiple programmers. Experience gained with POND users suggests that there are largely two groups of aquaculture personnel interested in such applications, namely commercial growers and educators. These two groups have substantially different interests and needs. Consequently, a single tool such as POND may not optimally meet the requirements of both groups. Recent development work on POND, and the need to involve users in the design process of such tools are discussed.

This abstract was excerpted from the original paper, which was published in Aquacultural Engineering, 23(1–3):103–119.


CRSP Research Report 00-154

AquaFarm: Simulation and decision support for aquaculture facility design and management planning

Douglas H. Ernst and John P. Bolte
Biosystems Analysis Group
Department of Bioresource Engineering
Oregon State University, Gilmore Hall 102B
Corvallis, OR 97331 USA

Shree S. Nath
Skillings–Connolly, Inc.
5016 Lacy Boulevard S.E.
Lacey, WA 98503 USA

Development and application of a software product for aquaculture facility design and management planning are described (AquaFarm, Oregon State University©). AquaFarm provides: (1) simulation of physical, chemical, and biological unit processes; (2) simulation of facility and fish culture management; (3) compilation of facility resource and enterprise budgets; and (4) a graphical user interface and data management capabilities. These analytical tools are combined into an interactive, decision support system for the simulation, analysis, and evaluation of alternative design and management strategies. The quantitative methods and models used in AquaFarm are primarily adapted from the aquaculture science and engineering literature and mechanistic in nature. In addition, new methods have been developed and empirically based simplifications implemented as required to construct a comprehensive, practically oriented, system level, aquaculture simulator. In the use of AquaFarm, aquaculture production facilities can be of any design and management intensity, for purposes of broodfish maturation, egg incubation, and/or growout of finfish or crustaceans in cage, single pass, serial reuse, water recirculation, or solar-algae pond systems. The user has total control over all facility and management specifications, including site climate and water supplies, components and configurations of fish culture systems, fish and facility management strategies, unit costs of budget items, and production species and objectives (target fish weights/states and numbers at given future dates). In addition, parameters of unit process models are accessible to the user, including species-specific parameters of fish performance models. Based on these given specifications, aquaculture facilities are simulated, resource requirements and enterprise budgets compiled, and operation and management schedules determined so that fish production objectives are achieved. When facility requirements or production objectives are found to be operationally or economically unacceptable, desired results are obtained through iterative design refinement. Facility performance is reported to the user as management schedules, summary reports, enterprise budgets, and tabular and graphical compilations of time-series data for unit process, fish, and water quality variables. Application of AquaFarm to various types of aquaculture systems is demonstrated. AquaFarm is applicable to a range of aquaculture interests, including education, development, and production.

This abstract was excerpted from the original paper, which was published in Aquacultural Engineering, 23(1–3):121–179.


CRSP Research Report 00-155

Applications of geographical information systems (GIS) for spatial decision support in aquaculture

Shree S. Nath
Skillings-Connolly, Inc.
5016 Lacey Boulevard S.E.
Lacey, WA 98503 USA

John P. Bolte
Department of Bioresource Engineering
Oregon State University
Corvallis, OR 97331 USA

Lindsay G. Ross
Institute of Aquaculture
University of Stirling
Stirling, FK9 4LA UK

Jose Aguilar-Manjarrez
Food and Agricultural Organisation of the U.N.
Viale delle Termi di Caracalla, 00100, Rome, Italy

Geographical information systems (GIS) are becoming an increasingly integral component of natural resource management activities worldwide. However, despite some indication that these tools are receiving attention within the aquaculture community, their deployment for spatial decision support in this domain continues to be very slow. This situation is attributable to a number of constraints including a lack of appreciation of the technology, limited understanding of GIS principles and associated methodology, and inadequate organizational commitment to ensure continuity of these spatial decision support tools. This paper analyzes these constraints in depth, and includes reviews of basic GIS terminology, methodology, case studies in aquaculture and future trends. The section on GIS terminology addresses the two fundamental types of GIS (raster and vector), and discusses aspects related to the visualization of outcomes. With regard to GIS methodology, the argument is made for close involvement of end users, subject matter specialists and analysts in all projects. A user-driven framework, which involves seven phases, to support this process is presented together with details of the degree of involvement of each category of personnel, associated activities and analytical procedures. The section on case studies reviews in considerable detail four aquaculture applications which are demonstrative of the extent to which GIS can be deployed, indicate the range in complexity of analytical methods used, provide insight into issues associated with data procurement and handling, and demonstrate the diversity of GIS packages that are available. Finally, the section on the future of GIS examines the direction in which the technology is moving, emerging trends with regard to analytical methods, and challenges that need to be addressed if GIS is to realize its full potential as a spatial decision support tool for aquaculture.

This abstract was excerpted from the original paper, which was published in Aquacultural Engineering, 23(1–3):233–278.


CRSP Research Report 00-156

Response to selection for body weight of nile tilapia (Oreochromis niloticus) in different culture environments

Remedios B. Bolivar
Freshwater Aquaculture Center
Central Luzon State University
Nueva Ecija 3120 Philippines

Gary F. Newkirk
Biology Department, Dalhousie University
Halifax, N.S. B3H 4J1 Canada

Within-family selection was practiced in Nile tilapia (Oreochromis niloticus) for 12 generations to increase body weight at 16 weeks of age. Response to selection was evaluated based on the progenies from two selected generations (S10, S13). Two variants of control lines (random-bred control and mean selected control) were used to account for environmental changes during the course of the selection experiments. A genetically improved strain (GIFT strain) and a commercial strain (Israel strain) were included in the performance evaluation. Eight experiments were conducted between 1993 and 1997. The different test groups were stocked communally in tanks, hapas, and ponds. Results showed that the selected group consistently had higher final body weights in the three test culture environments. The highest response was observed in the selection environment (tanks). A higher response occurred in the tanks for S10 (68% as deviation from the RBC group) and the response was still substantial at S13. A significant interaction was observed in the 1996 GxE study magnitude of growth difference within group from one environment to another. In this study, the pond environment provided more optimal condition for growth than the tank and hapa environments. The results of 1993 and 1997 GxE analyses did not show significant test group x environment interaction. Overall, the results of these growth evaluations showed that the selected group produced from within-family selection had improved growth performance and the selection response achieved in the tanks was apparent in hapa and pond environments.

This abstract was excerpted from the original paper, which was published in K. Fitzsimmons and J. Carvalho Filho (Editors), Tilapia Aquaculture in the 21st Century, Fifth International Symposium on Tilapia Aquaculture. American Tilapia Association and Departamento de Pesca e Aqüicultura/Ministério da Agricultura e do Abastecimento, Rio de Janeiro, Brazil, pp. 12–23.


CRSP Research Report 00-157

Criteria for selecting Nile tilapia and red tilapia for culture

Leonard L. Lovshin
Department of Fisheries and Allied Aquacultures
Auburn University, AL 36849 USA

Tilapia farmers often have problems deciding if Nile tilapia or red tilapia is the proper choice for culture. Nile tilapia is the most widely farmed tilapia world-wide but interest in red tilapia culture is growing rapidly. Nile tilapia are more dependable spawners and produce more consistent quantities of fry than red tilapia. Survival of eggs, fry and juveniles is higher for Nile tilapia and Nile tilapia are more tolerant of low water temperatures than most strains of red tilapia. Red tilapia often have higher market value, are more appropriate for culture in salinities above 10 g/l, and are easier to seine harvest from earthen ponds and transport live than Nile tilapia. Red tilapia need continual selection to retain their red color and pass the red color from generation to generation. Farmers should evaluate environmental conditions, culture system and markets before selecting either Nile tilapia or red tilapia for culture.

This abstract was excerpted from the original paper, which was published in K. Fitzsimmons and J. Carvalho Filho (Editors), Tilapia Aquaculture in the 21st Century, Fifth International Symposium on Tilapia Aquaculture. American Tilapia Association and Departamento de Pesca e Aqüicultura/Ministério da Agricultura e do Abastecimento, Rio de Janeiro, Brazil, pp. 49–57.


CRSP Research Report 00-158

Timing of the onset of supplemental feeding of Nile tilapia (Oreochromis niloticus) in ponds

Christopher L. Brown
Marine Biology Program
College of Arts and Sciences
Florida International University
North Miami, FL 33181 USA

Remedios B. Bolivar and Eddieboy T. Jimenez
Freshwater Aquaculture Center
Central Luzon State University
Nueva Ecija, Philippines

James Szyper
Sea Grant College Program
University of Hawaii at Manoa
Hilo, HI 96720 USA

An on-farm trial was conducted in seven (7) farms in Nueva Ecija, Philippines, to investigate the effect of two onsets of feeding on the growth, yield and survival of Nile tilapia. There were no significant differences on the performance data (final mean weight, daily weight gain, extrapolated gross fish yield, and survival rate) that were recorded in this study. The only statistically significant difference observed was in the total quantities of feed used in the trial. The 45-day onset in feeding produced a slightly higher mean gross value of the crop (P205,617 ha-1) compared with the 75-day delay (P197,063 ha-1) but by delaying the start of feeding, the costs were reduced such that the net value of the crop was improved (P124,242 ha-1 in 75-day vs. P106,026 ha-1 in 45-day delay).

This abstract was excerpted from the original paper, which was published in K. Fitzsimmons and J. Carvalho Filho (Editors), Tilapia Aquaculture in the 21st Century, Fifth International Symposium on Tilapia Aquaculture. American Tilapia Association and Departamento de Pesca e Aqüicultura/Ministério da Agricultura e do Abastecimento, Rio de Janeiro, Brazil, pp. 237–240.


CRSP Research Report 00-159

Analyses of various inputs for pond culture of Nile tilapia (Oreochromis niloticus): Profitability and potential environmental impacts

Yang Yi and C. Kwei Lin
Aquaculture and Aquatic Resources Management
School of Environment, Resources and Development
Asian Institute of Technology
P.O. Box 4, Klong Luang
Pathumthani 12120 Thailand

This paper presents profitability analyses and potential environmental impacts for Nile tilapia culture in ponds with a series progressive inputs. The sequential experimental stages to increase fish production through intensification were: 1) TSP only; 2) chicken manure only; 3) chicken manure supplemented with urea or urea and TSP; 4) urea and TSP; 5) continually supplemental feeding; 6) staged supplemental feeding; 7) feed alone.

Profitability analyses showed that the choices of input regimes with increasing economic gains are: 1) fertilizing ponds with moderate loading of chicken manure; 2) fertil-izing ponds with chicken manure supplemented with urea and TSP to balance nutrient loading and maintain water quality; 3) fertilizing ponds with urea and TSP at appropriate rates; 4) fertilizing ponds initially with urea and TSP, in combination with supplemental pelleted feed at 50% satiation level at later stage of grow-out cycle.

The analyses indicated that intensification of tilapia culture through staged inputs in ponds improved efficiency in land use and water consumption. The analyses also showed that the rate of nutrient loss as wastes and the nutrients required to produce 1 kg tilapia were markedly less in ponds with supplemental feed than those with high rate of fertilizer inputs.

This abstract was excerpted from the original paper, which was published in K. Fitzsimmons and J. Carvalho Filho (Editors), Tilapia Aquaculture in the 21st Century, Fifth International Symposium on Tilapia Aquaculture. American Tilapia Association and Departamento de Pesca e Aqüicultura/Ministério da Agricultura e do Abastecimento, Rio de Janeiro, Brazil, pp. 247–257.


CRSP Research Report 00-160

Concurrent design of hillside ponds for tilapia production

Brahm Verma, E.W. Tollner, and Jay Renew
University of Georgia
Driftmier Engineering Center
Athens, GA 30602-4435 USA

Tom Popma and J.L. Molnar
Auburn University, AL 36849-5406 USA

Daniel Meyer
Zamorano University
Tegucigalpa, Honduras

Farming on hillsides in Latin America has resulted in progressive deterioration of natural resources due to a combination of overgrazing, poor farming practices, deforestation, and poor water management. The introduction of tilapia production could improve the nutrition of farm families and local communities and provide a means of additional earning for improving economic status. An important aspect of designing and successfully introducing tilapia in Honduras and the adjoining regions is to have all stakeholders identify needs that include technical requirements as well as social and environmental issues important in the design of ponds and the production of tilapia. The fundamental method of pond design used here was based on the principles of concurrent engineering design methodology. In this method all stakeholders, hereafter referred to as "customers" (a person or entity that can impact the building, maintenance, and use of ponds for tilapia production), are identified. Our customer list included Honduras farmers, extension agents, government agencies, nongovernmental organizations, builders, and design engineers. Customer needs were identified and prioritized based on information from literature and input from experts representing perspectives of the identified customers. Design concepts were then tested using a US National Resource Conservation Service runoff model and spatial data pieced into a Geographical Information System. Concurrently considering needs of all customers in the design and selection of construction method provides a powerful method to have the user educated and invested in the design. This approach presents an increased possibility of introducing acceptable pond design and tilapia production as an economic enterprise in Honduras and Central America.

This abstract was based on the original paper, which was published in K. Fitzsimmons and J. Carvalho Filho (Editors), Tilapia Aquaculture in the 21st Century, Fifth International Symposium on Tilapia Aquaculture. American Tilapia Association and Departamento de Pesca e Aqüicultura/Ministério da Agricultura e do Abastecimento, Rio de Janeiro, Brazil, pp. 311–315.


CRSP Research Report 00-161

Microbiological hazards of tilapia culture systems

Casey McKeon, Edward Glenn, Charles P. Gerba, and Kevin Fitzsimmons
The University of Arizona
Department of Soil, Water and Environmental Science
College of Agriculture, 2601 East Airport Drive
Tucson, AZ 85706-6985 USA

Fecal coliform levels were measured in seven freshwater fish culture systems to assess potential microbiological hazards. Over a two month period, fecal coliform concentrations in two tilapia research facilities varied from 1 to 104 colony forming units (CFU) per 100 ml of water, at a mean level that could indicate the presence of human pathogens that may be hazardous to fish handlers and consumers. Over a one-month period, five commercial systems were found to contain Escherichia coli, Clostridium perfringens, Enterococci, and fecal coliforms. The concentration of fecal coliforms at the commercial sites was higher than the level found at the research facility. The presence of such organisms creates a potential for microbiological hazards in these systems. No Salmonella was detected in the systems. The source of these indicator organisms was not determined, nor were any host organisms obvious in the system. The findings in this study indicate that monitoring fish culture facilities for microbiological safety should be considered. In addition, workers should be aware of personal hygiene when entering, while working in, and when departing fish culture facilities.

This abstract was excerpted from the original paper, which was published in K. Fitzsimmons and J. Carvalho Filho (Editors), Tilapia Aquaculture in the 21st Century, Fifth International Symposium on Tilapia Aquaculture. American Tilapia Association and Departamento de Pesca e Aqüicultura/Ministério da Agricultura e do Abastecimento, Rio de Janeiro, Brazil, pp. 479–485.


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