Performance of Paralichthys orbignyanus sole in polyculture with Mugil platanus mullets in soil nurseries, in the autumn and winter period
The sole Paralichthys orbignyanus (Valenciennes, 1839) and the mullet Mugil platanus (Günther, 1880), are, respectively, carnivorous and detritivorous omnivorous fish found in the Lagoa dos Patos estuary, in southern Brazil. In order to evaluate the performance of sole and mullet in soil nurseries supplied with estuarine water, during the autumn and winter, two stocking densities of juvenile sole were tested, with an initial weight of 27.58 ± 5.53g and length 14.51 ± 1 cm, using 4 and 8 juveniles / m² (1: 4 and 1: 8) and Mugil platanus mullets, with an initial weight of 31 ± 4.02 g and a length of 14.00 ± 0.50 cm, using 8 juveniles / m² (1: 8), in a polycult of two treatments with three repetitions. The fish received extruded feed, in the proportion of 8% (temperature 16ºC), 4% (temperature & # 8805; 10ºC and <16ºC) of live weight and did not receive feed (temperature <10ºC), during autumn and winter, in a period of 192 days. Daily (09h), temperature, salinity, pH, O2D,% Sat O2, transparency and water color were observed. Fortnightly analysis of total ammonia was performed. The nurseries were fertilized monthly with 200g / m² tanned bovine manure. The biometry of sole and mullet was performed monthly on samples of 15% of the fish housed in each pond. Temperature, salinity and pH of the pond water influenced fish performance, however the oxygen levels were not limiting. The observed results indicate that M. platanus growth was not affected by P .orbignyanus stockings, as well as there was no growth difference between 1: 4 and 1 density sole:8 The survival of sole in 1: 8 stocking density was significantly (p <0.05) greater than survival in 1: 4 stocking density, and did not affect the survival of mullets in polyculture.