Fish Ponds

RESUMO-O incentivo da piscicultura em comunidades tradicionais de difícil acesso pode ser uma alternativa viável para o desenvolvimento territorial sustentável, contribuindo com a segurança alimentar e a geração de renda dentro dessas localidades. O cultivo de tilápias Oreochromis niloticus em tanques escavados é uma atividade largamente difundida no Brasil, apresenta uma cadeia produtiva bem consolidada, podendo ser viabilizada com um baixo grau tecnológico. Tendo em vista a demanda de representantes da Terra Indígena Bracuí pela inserção da piscicultura e a atuação do serviço de Assitência Técnica e Extensão Rural junto as comunidades tradicionais do Território Rural da Baía da Ilha Grande, este trabalho teve como objetivo avaliar o desempenho zootécnico do cultivo de tilápias em tanques escavados realizado na comunidade. Ao longo de seis meses, foram monitorados dois tanques escavados de produção semi-intensiva povoados com alevinos apresentando peso médio inicial de 1,28 gramas. Após 183 dias de acompanhamento os exemplares cultivados atingiram peso médio de 258,2 ±129,0 gramas no tanque 1 e 195,6 ±58,7 gramas no tanque 2. De um modo geral, os peixes monitorados neste estudo apresentaram um crescimento inferior quando comparado a outras áreas de produção no Brasil. Fatores como a dificuldade de adequação ao protocolo de rotinas de manejo produtivo, a impossibilidade de fertilização prévia dos tanques, o início do cultivorealizado no inverno e a utilização de ração com baixo teor de proteínas durante a fase inicial de cultivo provavelmente influenciaram no lento crescimento dos peixes. A continuidade das ações de ATER se faz necessária para o aprimoramento do cultivo de tilápias pelos indígenas Guarani na Terra Indígena Bracuí. Palavras chave: Angra dos Reis, aquicultura, Guarani, Oreochromis niloticus, viveiro escavado. TILAPIA POND CULTURE IN THE BRACUÍ INDIGENOUS RESERVE, RIO DE JANEIRO, BRAZIL ABSTRACT-The promotion of fish farming in traditional communities can be a viable alternative for sustainable rural territory development, contributing to food security and income generation in these locations. The tilapia breeding in earthen ponds is a widespread activity in Brazil, has a well-established production chain and can be made possible with a low technological level. Based on the demand of the Bracuí Indigenous Reserve representatives for the fish farming implementation and the local performance of the Technical Assistance and Rural Extension Service-ATER with the traditional communities of Baía da Ilha Grande Rural Territory, this work aimed to evaluate the zootechnical performance of the tilapia (Oreochromis niloticus) breeding in earthen ponds carried out in the community. Over six months, two semi-intensive earthen ponds containing tilapia fingerlings with initial weight 1.28 grams were monitored. After 183 days the fishes reached an average weight of 258.2 ± 129.0 grams in the "Pond 1" and 195.6 ± 58.7 grams in the "Pond 2". In general, the fishes monitored in this study showed a lower growth when compared to other production areas in Brazil. Factors such as the difficulty of indigenous in adapting to the production management protocol, the impossibility of ponds previous fertilization, the beginning of breeding in the winter season and the use of low protein diets in the initial growth stage probably influenced the tilapia slow growth. The continuity of ATER's actions is necessary for the improvement of tilapia pound culture in the Bracuí Indigenous Reserve.

Aeration is increasingly used to improve water quality and increase yields in aquaculture ponds. Surface aerators increase oxygenation by creating a greater area of contact between water and air –a process that also favors higher evaporation rate.Evaporation results in heat loss from water bodies; therefore, it affects temperature that is an important factor determining the growth rate of fish. Despite the importance of water temperature on fish growth and the increase in water use associated with greater evaporation, little is known about the increase in evaporation caused by aeration. This study evaluated the influence of aeration on evaporation and water temperature in ponds, and compared effects of different types of aerators on pond evaporation and water temperature. Water loss by evaporation and water temperature were monitored in ponds with different rates of aeration (9.2, 18.4, 27.6and 36.9 kW/ha) during the first year of the study. In the second year, the effects of different types of aerators on evaporative loss and water temperature were measured. Both surface water temperature and temperature at a 70 cm depth were different for ponds with different numbers of 0.37-kW vertical pump aerators (p< 0.0001). The decreases in surface water temperature with 9.2 kW/ha or 18.4 kW/ha of aeration with paddlewheel aerators were more than that of both rates of 'h'-unit™aerators and non-fertilized control ponds (p< 0.001). An aeration rate of 18.4 kW/ha by the Air-O-Lator, paddlewheel and ‘h’-unit™aerators resulted in 57.49 %, 54.24 % and 9.45 % increase in pond evaporation respectively. 

Influences of Different Types and Rates of Mechanical Aeration on Water Temperature and Evaporation Rate in Aquaculture Ponds. Available from: https://www.researchgate.net/publication/293175635_Influences_of_Different_Types_and_Rates_of_Mechanical_Aeration_on_Water_Temperature_and_Evaporation_Rate_in_Aquaculture_Ponds [accessed Feb 9, 2016].