Julio Ferraz de Queiroz

Role of aquaculture pond sediments in sequestration of annual global carbon emissions

Aquaculture ponds sequester about 16.6MTyr(-1) of organic carbon worldwide representing around 0.21% of annual, global carbon emissions.

Feasibility of Retention Structures, Settling Basins, and Best Management Practices in Effluent Regulation for Alabama Channel Catfish Farming

The United States Environmental Protection Agency has initiated rule making for aquaculture effluents. The contents of the rule will not be finalized until June 2004, but effluent containment in retention structures, effluent treatment in settling basins, and best management practices have been components of rules for other animal production facilities. The main aquaculture activity in Alabama is pond culture of channel catfish (Ictalurus punctatus). Fish are harvested with seines, and it is not necessary to drain ponds more than once in 5 to 10 years. Thus, effluents result mainly from storm overflow in winter and early spring. Catfish ponds in Alabama cannot be operated without effluent. A retention structure of enormous size would be necessary to retain storm overflow without discharge. Treatment of storm overflow by sedimentation also is not feasible. Settling basins with enough volume to provide a hydraulic retention time of 8 h would often be larger than production areas. Most catfish farms in Alabama are built to property lines or streams, and there would seldom be enough space available for settling basins to treat draining effluent. The best approach to effluent management in Alabama catfish farming appears to be the development and implementation of best management practices (BMPS) to reduce the volume and improve the quality of effluents. Considerable research has been conducted on water quality in catfish production ponds, and there is a large database to use in forming BMPs. Several categories of BMPs are provided for consideration as follows: BMPs to reduce effluent volume; BMPs to minimize suspended solids through erosion control; BMPs to improve pond water and effluent quality; BMPs for use of therapeutic agents and other chemicals; BMPs for siting and construction of new ponds or farms. Suggestions on how a formal system of BMPs could be prepared for Alabama catfish farming are given.

Considerations on the Use of Malachite Green in Aquaculture and Analytical Aspects of Determining the Residues in Fish: A Review

Aquaculture in Brazil has shown expressive development since the 1990s with growth rates superior to those of cattle and poultry. In order to achieve greater productivity, intensive fish cultivation systems are employed, which can cause greater susceptibility to diseases caused by viruses, bacteria, fungi, and parasites. The reduced availability of veterinary medications approved for use in aquaculture in Brazil has lead fish farmers to the indiscriminate use of several chemical substances with antimicrobial activity, such as the dye malachite green (MG). As a result of this use, residues of MG and its main biotransformation product, leucomalachite green (LMG), may be present in fish available for consumption. The presence of residues of these compounds represents a risk to human health due to their toxicity, as well as a potential impact on the environment, and could also raise barriers for commercialization in the country and for exportation. The objective of this review is to provide the context and evidence of the use of MG in aquaculture and of its toxicological and legislative aspects. A review of the analytical methods used to determine MG residues in fish, with emphasis on mass spectrometry, is also presented.

Lime application methods, water and bottom soil acidity in fresh water fish ponds

Alguns metodos para determinar a quantidade de calcario necessaria para corrigir a acidez do fundo dos viveiros de piscicultura estao disponiveis e rotineiramente em uso, mas ainda nao existe um consenso se e mais eficiente fazer a aplicacao diretamente no fundo ou sobre a superficie da agua apos o abastecimento dos viveiros. Alem disso, existem poucas informacoes disponiveis sobre ate que profundidade o calcario reage com o sedimento do fundo ao longo do tempo, e se a profundidade na qual ocorrem as reacoes e diferente quando o calcario e aplicado sobre a superficie da agua ou sobre o solo. Dessa forma, tres tecnicas para calagem foram avaliadas em viveiros com solo argiloso em uma piscicultura comercial de acordo com os seguintes metodos: aplicacao direta sobre a superficie da agua do viveiro, distribuicao uniforme sobre o fundo do viveiro vazio, distribuicao uniforme sobre o fundo do viveiro vazio seguida da aragem. A eficacia da aplicacao do calcario agricola nao diferiu entre os metodos de tratamento. O calcario agricola reagiu rapidamente para aumentar a alcalinidade e a dureza total da agua dos viveiros para concentracoes aceitaveis apos duas semanas. O aumento do pH do sedimento se completou essencialmente apos um a dois meses, e o calcario agricola nao teve efeito sobre as camadas de sedimento abaixo de 8 cm. A aracao do fundo dos viveiros para incorporacao de materiais e desnecessaria, consome tempo e e dispendiosa; a calagem pode ser feita de forma eficaz em viveiros cheios.

Environmental and economic assessment of fee-fishing in São Paulo State, Brazil.

Abstract According to feed producers, aquaculture in Brazil generates an annual income of about US

Emergy assessment of integrated production systems of grains, pig and fish in small farms in the South Brazil

200 million and is growing at an annual rate of 15%. More than 300,000 people are involved, including fish and shrimp farmers, feed companies, technicians and equipment manufacturers. The growth of the aquaculture industry has given rise to concerns about such environmental issues as water pollution and the conversion of land to ponds. “Fee-fishing” is the maintenance of ponds so that people can fish from them, primarily by line, usually for an entrance fee and for a fee paid per kilogram of fish caught. Attendant activities on the farm site, such as restaurants and ecorural tourism, also generate considerable revenues. Fee-fishing started on marginal areas unsuitable for agriculture or other activities, but it has recently expanded rapidly to occupy former farmland and areas of land close to the large urban centers. Fee-fishing either supplements the income or is the main source of income for many people. It generates 60 million (U.S.) per year at the Piracicaba River watershed in São Paulo State alone. The annual average net income of the fee-fishing farms studied equals 46% of the total costs, with variations from 8% to 120% over the total costs per year. In 22% of the fee-fishing areas, the pH and dissolved oxygen are controlled, and in the worst cases (almost 6% of the sites sampled), none of the physical and chemical parameters of water quality are controlled. The fee-fishing farms evaluated in this study usually have low-quality water. Only 6% of the fee-fishing farms have some sort of effluent treatment system. Fee-fishing farms should improve management to enhance their attractiveness to tourists and to prevent negative environmental impacts.