Abstract

PEFAUR, Jaime E.  and  SIERRA, Nancy M.. Distribución y densidad de la trucha Oncorhynchus mykiss (Salmoniformes: Salmonidae) en los Andes venezolanos. Rev. biol. trop [online]. 1998, vol.46, n.3, pp.775-782. ISSN 0034-7744.

Spatial distribution and relative abundance of wild rainbow trout populations were studied in 68 stations located between 500 and 4000 masl in seven hydrological basins of the most important Andean rivers of Venezuela during a year of sampling. A total of 612 individuals were obtained above 1700 m. Most fishes were obtained from the Chama ( 43%), Motatán (21%) and Santo Domingo (32%) rivers, very few in the Negro (1.75%) and La Grita (0.33%) rivers, and none in the Escalante and Mocotíes rivers basins. Adult males were more abundant than females in a 2.15:1 proportion. Juveniles made a 56.7% of captures, with a proportion of 1.30 juveniles per adult. Individual sizes varied from 2.0 to 21.8 cm, most within the interval 5.1 - 10.0 cm; the weight of specimens also showed an ample variation, with a maximum of 317.0 g.

Keywords : Rainbow trout; Oncorhynchus mykiss; Andean rivers; hydrological basins; altitudinal distribution.