(Aspects of the populational structure of the "pescada-do-Piauí­­ "Plagioscion squamosissimus (Heckel, 1840) (Osteichthyes, Sciaenidae), in Bariri Reservoir, Tietê River, São Paulo State, Brazil)

Abstract

In this paper, 1,189 specimens of "pescada-do-Piauí­­", Plagioscion squamosissimus (Heckel, 1840), caught in Bariri Reservoir, during the period of January 1980 to December 1982, were analyzed. The objective is to study aspects of popuIational structure in distinct seasons of the year. It is observed in this period a predominance of females (61.23%). The females attain superior length in relation to males and they are predominant in the larger length classes. The males reach the length of first maturation (_pm) with 18.2 cm of total length and the females, with 20.6 cm. After the total length of 31.0 cm, all the specimens of this population, males and females, are suitable to reproduction ( 100%). The relationship between total length an body weight, determined to males and to females, resuIted:

males:       W = 0,0159 L^2.8981

females:   W = 0,0178 L^2.8873