Dynamic population from triportheus albus, t. angulatus and t. auritus (Characiformes: Characidae) in Amazonian central lakes

Abstract

In the Amazon the fishing is considered an important source of income and animal protein for the people in the region. Among the different fish species that landed in the market and fairs stand out Triportheus albus, T. angulatus and T. auritus. Considering the reduction of some fish stocks in the region, both the quantity and the size of some species, the research proposes to determine the growth parameters, mortality and length-weight relation of these species in floodplain lakes, Manacapuru, AM. The parameters were estimated by analyzing the length frequency distribution with the help of the routine "scan of values of k" method ELEFAN I program FISAT II. The values for each species were: T. albus L∞=24.68cm, k=0.86/year, Ø '= 2.71, A0.95=3.48years, Mp=1.76/year, Mt=0.85/year, Pt=0.0398*Cp2.6303; T. angulatus L∞=26.78cm, k=0.77/year, Ø '= 2.74, A0.95=3.89years, Mp=1.60/year, Mt=0.76/year, Pt=0.0294*Cp2.8599 and T. auritus L∞=27.83cm, k=0.65/year, Ø '= 2.70, A0.95=4.68years, Mp=1.40/year, Mt=0.63/year and Pt=0.0542*Cp2.5094. These species showed rapid growth, high mortality, low life expectancy and short life cycle. It is suggested the parameters population should be continuously monitored to be used as a tool in the stock analysis.