POPULATIONS AND PRODUCTION OF FISH IN 2 SMALL TRIBUTARIES OF THE PARANA RIVER, PARANA, BRAZIL

Mean biomass ((B) over bar) and production (P) of fish in two small tr ibutaries of the Parana River (Parana, Brazil) were 61 kg ha(-1) and 4 8 kg ha(-1) yr(-1) in the Caracu River and 29 kg ha(-1) and 26 kg ha(- 1) yr(-1) in the Agua do Rancho River, respectively. Matrix correlatio n analysis revealed high positive correlations of both (B) over bar an d P to maximum depth and hiding places and, at a lower level of signif icance, to mean depth, pH and oxygen level. Lower (B) over bar and P v alues were found in the Agua do Rancho River, whose valley has retaine d a more natural character, rich canopy and scarcity of macrophytes, b ut also lower conductivity and nitrogen and phosphate levels than thos e in the Caracu River.