Effects of salinity on eggs, larvae and juveniles of Paralichthys orbignyanus sole
Author: Luciano de Siqueira Freitas (Currículo Lattes)
Supervisor: Dr Luís André Nassr de Sampaio
Abstract
The objective of this work was to evaluate the effects of salinity on artificial fertilization and the cultivation of larvae and juveniles of the sole Paralichthys orbignyanus. The influence of salinity (10, 15, 25 and 35) on artificial egg fertilization was evaluated. At salinity 10, there was no fertilization, but after salinity 15, fertilization rates were directly proportional to salinity, being equal to 15, 40 and 75% at salinity 15, 25 and 35, respectively. Although fertilization occurred at these three salinities, the larvae hatched only at salinity 35. The resistance of larvae (6 and 16 days old) and juveniles (30, 45 and 60 days old) of sole to water was evaluated. candy. No larvae with 6 days of age survived fresh water, and the survival of larvae with 16 days of age was 93%.No juvenile mortality was observed during this experiment. The effect of different salinities (5, 10, 20 and 30) on survival, growth and settlement time for sole larvae was evaluated. No larva survived salinity 5, but after salinity 10, survival increased proportionally with the increase in salinity. At salinity 10, less growth was detected (P <0.05) compared to salinities 20 and 30, which were similar to each other (P> 0.05). Salinity did not affect the individuals' settlement time, as they all started the settlement process 23 days after hatching and this process was completed 30 days after hatching in all salinities. The survival and growth of juveniles grown at salinities 0, 5, 10 and 30 were studied. Salinity did not affect juvenile survival (P> 0.05), however the growth of juveniles grown at salinity 10 was significantly higher (P <0.05) than the others, while those grown in fresh water showed the lowest growth (P <0.05). The results obtained indicate that dependence on sole for high salinities is inversely proportional to their age, requiring ocean water (salinity 35) for their reproduction and brackish water (salinity 20) for their larviculture, while their fry can even be grown in water sweet, without prejudice to its survival, although the growth is greater in salinity water 10.