A study of the annual abundance fluctuation, temporal distribution and size composition of Aegla castro Schmitt, 1942 was carried out at the Buraco do Padre, Quebra-Perna River, Tibagi River Basin, in the municipality of Ponta Grossa, Paraná State. The samplings were done monthly, from February/97 to January/98 with the aid of a hand net and screens at three stations, under an effort of 120 minutes. The average air temperature ranged from 15.0ºC (May, July, September and October) to 24.3ºC (December and January), and the water temperature from 15.8ºC (July) to 22.3ºC (December). The dissolved oxygen oscillated from 95.7% (March) to 100. 2% (August) saturation, and the pH from 6.1 (July) to 7.2 (September). The water flow speed varied from 0.2 m/s to 1.2 m/s. Sulfates and phosphates had values less than 0.2 ppm and the ammonia values alternated from 0.1 to 0.6 ppm. A total of 827 specimens were obtained, among which 384 males, 311 females and 132 juveniles. The abundance of Aegla castro varied from 27 (July/97) to 204 (September/97). In the Station 1 higher number and larger specimens were obtained with predominance of males. Juveniles and adults of both sexes occurred in all three sites, but the proportion between juveniles and adults was different. So, these habitats are appropriate to the development of these animals. Males grow up larger than females, due to the reproductive effort of the last ones.
Crustacea; Decapoda; Aegla castro; abundance; size composition; Ponta Grossa; Paraná State