Influence of aquaculture effluents on the growth of Salvinia molesta

Abstract

Objective: Aquaculture generates social and economic benefits, but also causes impacts on the environment. One of the major impacts is the release of untreated effluents into rivers, reservoirs, and lakes, which can affect aquatic populations and communities. In this study, we tested the hypothesis that effluent from aquaculture favors the growth of the floating aquatic macrophyte Salvinia molesta; Methods: The study was carried out in a non-impacted reservoir (NIR) and in another reservoir (IR) that is impacted by discharges of aquaculture effluents, and lasted for nine months. In each of the reservoirs, we installed four experimental units containing 10 ramets of S. molesta. Monthly, we measured limnological variables of the water and the biomass of S. molesta in both reservoirs; Results: The temperature, turbidity, electrical conductivity, alkalinity, chlorophyll-a, total Kjeldahl nitrogen, and total phosphorus were higher in the IR in all the collection months. At the end of the experiment, the concentrations of total nitrogen and phosphorus in the biomass of S. molesta from the IR were higher than those in plants from the NIR. The estimated support capacity (K) for S. molesta in the NIR was 3.0 ± 0.7 g DM.m-2 and in the IR was 37.4 ± 2.4 g DM.m-2 ; Conclusions: It was concluded that the discharge of aquaculture effluent modifies the limnological characteristics of the water of the receiving reservoir, and that the growth of Salvinia molesta is favored by the aquaculture effluent, because of the increases in the concentrations of nitrogen and phosphorus in the water.

Biodiversity

“…A study in Brazil compared two reservoirs-one impacted by cage aquaculture and one without cage aquaculture (Pistori et al 2010). The chlorophyll a concentration was higher in the reservoir with cage aquaculture than in the other reservoir.…”

Overview of strategies that contribute to the environmental sustainability of pond aquaculture: rearing systems, residue treatment, and environmental assessment tools

“…In the tropical region, the biomass of the free‐floating macrophyte Salvinia molesta was 12.5 times higher in a reservoir that received aquaculture effluent than in a reservoir that did not receive this effluent (Pistori et al . ). Therefore, there is an increase in the water treatment costs to reach sanitary levels for human consumption, and it is necessary to invest in technology to remove organic matter, nutrients, toxins and pathogens (Tundisi ; Oliveira et al .…”

“…In aquatic environments, such as lakes, reservoirs, river and ponds, the increase in nutrient concentration favours the development of different macrophyte species (Pieterse & Murphy 1990;Thomaz et al 2005;Camargo et al 2006;Pitelli et al 2008;Bornette & Puijalon 2011). In the tropical region, the biomass of the free-floating macrophyte Salvinia molesta was 12.5 times higher in a reservoir that received aquaculture effluent than in a reservoir that did not receive this effluent (Pistori et al 2010). Therefore, there is an increase in the water treatment costs to reach sanitary levels for human consumption, and it is necessary to invest in technology to remove organic matter, nutrients, toxins and pathogens (Tundisi 2003;Oliveira et al 2014).…”

Use of Eichhornia crassipes dry matter as organic substrate for germination and initial growth of corn

“…Aquatic plants (macrophytes) play an important role in the structure and function of aquatic ecosystems (Chambers et al 2008, Mormul et al 2010 97-102,2018(Páez-Osuna et al 1997. In Brazil, unwanted proliferation of macrophytes has been reported in hydroelectric dams and environments impacted by the release of wastewater from domestic, industrial and aquaculture activities (Marcondes et al 2003, Pistori et al 2010.…”