The influence of environmental factors (temperature, light and nutrients) on macrophytes growth and the evaluation of their nutritional value for aquaculture

• Grant number: 11/24157-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): February 01, 2012
• Effective date (End): December 31, 2012
• Field of knowledge: Biological Sciences - Ecology - Applied Ecology
• Principal Investigator: Odete Rocha
• Grantee: Maíra Alcântara Proença
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Aquatic macrophytes have great relevance for freshwater aquatic ecosystems, being responsible for nutrient stocking and also play a relevant role in the energy flow of their environment, at the base of the food chains through direct herbivory as well as via detritus. Under some conditions the growth of aquatic macrophytes can become a nuisance with adverse consequences to both, the local aquatic biota and humans in the region. Abiotic factors (temperature, nutrients and light) are related to the excessive growth of macrophytes. In this case they have to be controlled and one of the practical aspects of the management could be the mechanical harvesting and the use of the biomass as a nutritional source. This requires a deep knowledge of each individual species. The aim of present research work is to evaluate the growth and biomass production of floating macrophytes under different abiotic conditions and to investigate its nutritional value aiming to use their biomass as a food complement to feed invertebrates and fish of aquaculture interest. For that growth and production experiments will be performed under controlled conditions with the macrophytes Salvinia minima and Lemna minor under different combinations of temperature, light and nutrients. The nutritional value of the biomass produced will be evaluated trough biochemical analyses of lipid, carbohydrate and protein content. Their value as food complement for the invertebrate micro-crustaceans Daphnia sp, Simocephalus sp and Hyalella sp and three species of fishes will be evaluated regarding their growth performance.(AU)