A study on incubation of Brown Trout (Salmo trutta sp.) eggs and feeding of fry

Abstract

In this study, spawning, incubation success or survival rate of brown trout and initial feeding of fry were investigated. The wild broodstock in this study were caught in Akcay river in Sapanca. In July 2008, 7 female and 1 male fish with a body weight between 300-350 g were brought to the Istanbul University, Faculty of Fisheries Sapanca Inland Waters Research Center (Adapazari, Turkey). These fish were kept in fiberglass adaptation tanks and were fed fresh rainbow trout meat. During this period, fish were fed with 9 mm pelleted feed. In June 2009, when fish had reached an average weight of 2500-3000 g, the first biometric measurements on the fish were performed. In early March 2010, about 3000 eggs were stripped from one female broodstock and sperms from the male brown trout. After the fertilization, the eggs were placed in horizontal incubators. The eye development started on the 21st day and hatching began on the 30th day. Hatching was found to be approximately 74%. When fish run out of their yolk sac, fry were divided into three groups of 600 individuals per tank and kept under same incubation conditions. Fry were fed feeds such as Artemia sp., fresh lamb liver, microdiets (300, 500 and 700µm) and extruded pellet feed (1mm). For the first group, fry were started on Artemia for seven weeks and continued on microdiets and extruded pelleted feed. For the second group, fry were started on microdiets and continued on extruded pellet feed. For the third group, fry were started on fresh lamp liver for a month and continued as the other groups. Fry were fed multiple times a day to satiation. Water used in the experimental tanks was from the research center. Average parameters recorded included water temperature of 11.5oC, pH of 7.86 and DO of 9.6 mg/L. At the end of the experimental period, the number of dead fry were 77, 104 and 123 in the first, second and third groups respectively. In conclusion, the present study indicated that the first generation eggs incubation from wild broodstock brown trout adapted to culture conditions successfully. However, further studies on the first feeding at the fry stage are encouraged. Keywords: Brown trout, broodstock culture, egg incubation, survival, fry nutrition