Resumen

GONZALEZ, Ángel; MENDOZA, Jeremy; AROCHA, Freddy  y  MARQUEZ, Arístide. Gillnet selectivity in the capture of barred sorubim Pseudoplatystoma fasciatum in the middle Orinoco basin. Zootecnia Trop. [online]. 2008, vol.26, n.1, pp.63-70. ISSN 0798-7269.

An indirect method of the comparison of the captures of Pseudoplatystoma fasciatum by nets of 10 cm of mesh opening with the captures with nets of 7 cm of opening was used to study the selectivity, being used 224 fish captured with nets of 10 cm opening (30 - 84 cm total length) and 76 fish captured with nets of 7 cm opening (28 - 51 cm of total length) in a lagoon flood of the middle Orinoco during the dry season. The selectivity parameters were estimated using log-lineal models in four statistical distributions (normal with common variance, normal with different variance, gamma and log-normal), assuming for the two cases a fishing power equally for each mesh and proportional to the size of the mesh. The smallest value in the variance was used as an approach of kindness of adjustment of the models, providing the best adjustment the normal pattern with different variance and a power of proportional fishing to the size of the mesh. The optimum size of capture of P. fasciatum for the 10 cm mesh was estimated at 51 ± 8.9 cm total length. These nets are frequently used in the basin of middle Orinoco and according to the results the average of the length in the captures is shortly smaller than the size of first sexual maturity of the species and great part of the captured fish don’t have the minimum size required by the fishing regulations.

Palabras clave : Fishing administration; Orinoco; Pseudoplatystoma fasciatum; gill1net; optimum size.

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