THE EFFECT OF AGRICULTURAL PESTICIDES ON THE REPRODUCTION OF NATIVE FISHES/O EFEITO DE DEFENSIVOS AGRICOLAS SOBRE A REPRODUCAO DE PEIXES NATIVOS/EL EFECTO DE LOS PLAGUICIDAS AGRICOLAS EN LA REPRODUCCION DE PECES NATIVOS

Agricultural pesticides are products used in rural environments aimed at controlling pests, however, improper use can lead to contamination of aquatic environments. The objective of this study was to evaluate the effects of glyphosate, malathion, and casugamycin on the fertilization, hatching, and survival rates of tambaqui larvae. Two pairs of tambaqui (females 7.73 [+ or -] 1.54 kg and males 6.18 [+ or -] 0.65 kg) were subjected to artificial reproduction using the synthetic GnRH analog Sincrofort[R]. Three experiments were conducted: (i) concentrations of 0.0; 2.0; 4.0; 6.0; 8.0; 10.0; and 14.0 mg [L.sup.-1] of glyphosate were tested, (ii) concentrations of 0.0; 0.25; 0.5; 0.75; 1.0; 1.25; and 1.5 mg [L.sup.-1] of malathion, and (iii) concentrations of 0.0; 0.25; 0.5; 0.75; 1.0; 1.25; and 1.5 mg [L.sup.-1] of casugamycin. The eggs were incubated in plastic containers, and the treatments were the different concentrations evaluated, all with five replications. A container with 20 eggs was considered as one experimental unit. The experiment was conducted under controlled conditions, at room temperature, and with low light. Data were subjected to analysis of variance. The treatment with incubation water without glyphosate showed the best fertilization, hatching, and survival rates (p