Spatial and temporal limnological changes of an aquaculture area in a neotropical reservoir

Abstract

This study evaluated the spatial and temporal limnological characteristics of an aquaculture area in the Itaipu reservoir, Brazil. During a one-year period, water quality parameters were evaluated in seven collection sites using a fish culture system as the reference point. A regression analysis was performed on water transparency versus chlorophyll a and total phosphorus versus chlorophyll a. The trophic state index (TSI) was calculated using data from water transparency, chlorophyll a, and total phosphorus. In addition, a study of the carrying capacity was conducted in situations of high and low flow and rainfall based on 725 m3 s−1 and 298 mm and 34.5 m3 s−1 and 11 mm, respectively. No difference was observed in the parameters of water quality and the TSI in relation to the collection sites; these parameters only varied significantly throughout the seasons. The regression analysis showed that increased total phosphorus in the environment leads to increase in chlorophyll a concentrations and consequently decreased water transparency. Evaluation of the carrying capacity demonstrated that under conditions of high precipitation and flow it is possible to produce 623.7 tons of fish per year, which is above the total cultivated in fish farms at the study site.

Assessment of Hydrobiological and Soil Characteristics of Non-Fertilized, Earthen Fish Ponds in Sindh (Pakistan), Supplied with Seawater from Tidal Creeks

“…The TSS calculation in this study should be treated only as a gross estimation of the overall planktonic abundance in the Garho ponds, given that there are numerous factors which influence the process of limnological change, especially in aquaculture fish ponds [130][131][132][133]. However, most noticeably, these basic results complied with the relative quantification of planktic species, which has shown the reduction of zooplankton richness in VI, and of both zoo-and phytoplankton in XII.…”

Produção de pós-larvas de tilápia do Nilo em sistema de recirculação de água com tanques retangulares e diferentes designs de entrada de água

“…Não foi aplicado sistema de controle de temperatura, a qual foi influenciada pelas mudanças da temperatura atmosférica no decorrer do estudo. A concentração de oxigênio dissolvido foi maior quando a temperatura da água foi menor, o que corrobora com os resultados descritos por LEWANDOWSKI et al (2018). Isso ocorre pois à medida que a temperatura aumenta, a solubilidade do oxigênio diminui e a água atinge a saturação mais rapidamente (VAROL & ŞEN 2009).…”

Trophic state index ( TSI ) and carrying capacity estimation of aquaculture development; the application of total phosphorus budget

“…Thus, these areas had a relatively higher level of productivity. According to Sharma et al (2010) and Lewandowski et al (2018), the light availability and intensity, and concentrations of total phosphorus and chlorophyll-a influence the development of algae biomass both directly and indirectly, thus providing insight into the abundance of biological productivity in the water body. Although sampling points located at distances >3 km from the fish cage were mesotrophic, there was a trend towards becoming a eutrophic state.…”

“…Effects resulting from the establishment and operations of aquaculture farms include various associated effluents such as feed wastes, faeces, pesticides and antibiotics that could reduce water quality (Cretu et al, 2016;Freeman et al, 2012;Khairy et al, 2020;Lewandowski et al, 2018;Miod et al, 2009;Sawestri et al, 2021).…”