Individual growth of Drepanotrema cimex (Pulmonata: Planorbidae) from Arenalcito pond, natural reserve multiple uses Martin García Island, Buenos Aires, Argentina

Brazilian Journal of Biology

M Martín-stella¹  C Díaz-ana¹  A Rumi¹ 

关键词: Drepanotrema cimex;    individual growth;    Bertalanffy equation;    Martín García Island;    Drepanotrema cimex;    crescimento individual;    equação Bertalanffy;    Ilha Martín García;   

DOI  :  10.1590/S1519-69842013000400020

来源: SciELO

【 摘 要 】

The species of the genus Drepanotrema, most of them endemic to the Neotropical region, belong to the Planorbidae. Of the nine species of this genus, six are found in Argentina. The present investigation analysed the individual growth of Drepanotrema cimex in Arenalcito pond (34°11′ S, 58°15′ W), Martín García Island Natural Reserve of Multiple Uses, Buenos Aires Province, Argentina. A total of 14 samples were collected (n = 1931) from February 2006 to June 2007. Five environmental variables were measured: water temperature, dissolved oxygen (mg L–1), electrical conductivity (µS cm–1), total dissolved solids, and pH. The individual growth of the species was analysed mathematically by means of the von Bertalanffy equation, where: Lt = 5,6(1-e–2,0592 (t–0,293)). The parameter L∞ was estimated by the Ford-Walford Method. The population of D. cimex was characterised by a complex and dynamic size structure throughout the annual cycle. The analysis of the curves revealed unimodal (2006) and polymodal (April to June 2007) distributions, which pattern served to identify the existence of cohorts within the population studied.

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