Abstract

GONZALEZ, Ángel R; MENDOZA, Jeremy; AROCHA, Freddy  and  MARQUEZ, Aristide. Age and growth of the striped catfish Pseudoplatystoma orinocoense of the average Orinoco in Venezuela. Zootecnia Trop. [online]. 2010, vol.28, n.2, pp.283-285. ISSN 0798-7269.

Considering the importance of the barred sorubim Pseudoplatystoma orinocoense in the artisanal fishery landings of the middle Orinoco region, in this study age and growth were estimated using ring counts from dorsal spines of 120 fish. Sampling was carried out in the mid-Orinoco channel and a flood lagoon using a gillnet with 10 cm mesh opening. Parameters of the von Bertalanffy growth model were estimated for back-calculated length at age data using maximum likelihood methods. The presence of Lee´s phenomenon in back calculated lengths at age led to the estimation of 2 growth curves: the first for all back calculated data (L_t= 112,6 (1-exp^{(-0,08 t+0,055)})) and the other excluding back calculated data at ages 1 and 2 (L_t = 106,1 (1-e^{-(0,089 t-0,082)})). A non parametric bootstrap procedure was used to estimate model parameter confidence intervals. Results indicate a relatively slow growth rate for P. orinocoense with a 95% confidence interval of estimated average longevity understood between 28 and 42 years, that they agree with some works reported for the same species and kindred species in different hydrographic basins of South America.

Keywords : Middle Orinoco; artisanal fishery; Pseudoplatystoma orinocoense; age; growth.

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