Crescimento do preto-velho, Ancistrus ramunculus (Muller; Rapp Py-Daniel; Zuanon, 1994) do Rio Xingu entre os municípios de Altamira e Senador José Porfírio, estado do Pará.

Abstract

South America is the richest freshwater ichthyofauna in the world and among the countries that comprise it, Brazil is considered the richest in terms of this ichthyofauna on a world scale, but little known in Ecology, Biology and Systematics, making it difficult to better understand several species. , including the species Ancisírus rannculus. The present work contributes to the knowledge of the growth of the Ancistrus ramunculus species captured in the Xingu River within the scope of the Project Sustainable Development of Ornamental Fish in the North Region in the years 2004 and 2005. The collections were carried out in the months of May, July, September and November 2004 and March, May, September and November 2005, the samples being taken to the Dynamics laboratory at Cepnor/Ibama. To determine the parameters of the Von Bertalanfy growth curve, the methods of Bhattacharya and Gulland and Holt and the ELEFAN I system were used. In addition, it determines the growth rate according to Taylon. From the data analysis, the morphometric relationship was obtained with the equation between the total length and the pattern being CT = 12152*CP + 0.3894, excellent linear correlation coefficient (r = 0.9907), deterministic index (rº = 0.9814), in the frequency distribution of lengths the most representative sample was from the month of September 2004, in the measures of central tendency and dispersion the P year with the highest number of individuals sampled was in 2004, in the average length per stretch of the Xingu river, section 1 covering the sites Curicas, Altamira, Maçonario, Parati and Alonso was found the largest individuals and section 2 covering the sites Ilha da Fazenda and Landy, section 3 covering the sites Poço do Jaú and Jurucuá and section 4 covering Belo Asymptotic length of Loo = 20.85 cm and growth constant K = 0.40 year *, in the Bhattacharya method 3 cohorts were found and by the methods of Gulland and Holt found Loo = 16.48 cm and K = 1.57 years - and longevity was estimated at 2 years. For Ancistrus ranunculus, the relationship between total and standard length was obtained with excellent linear correlation. The largest individuals were sampled in the section covering Curicas, Altamira, Maçonario, Parati and Alonso. The most representative sampling of the preto-velho population was carried out during the dry season. smaller shallow areas Ancistrus - ranunculus is a small species with Leo = 16.48 cm growth rates of 1.57 years and possessing short life and fast growth.