Composting in residues management of freshwater fish

Abstract

A trial was conducted to evaluate the contribution of composting on the suitable management of residues of freshwater fish. The treatment consisted of two stages: the first one was carried out in a composting cell and the second one in a pile. Wood shavings and residues of freshwater fish were mixed in a 3:1 ratio. Data were analyzed through ANOVA and polynomial regression and the averages were compared with the Tukey test at 5%. The results herein obtained showed that composting is an efficient alternative for the management of residues of freshwater fish. The almost intact structure of wood shavings at the end of process, along with the fast decomposition of residues of freshwater fish and the high C/N ratio during 90 days of composting, suggest that a higher proportion of the protein source could have been used. The structuring agent allows the formation of immature composts at the end of 90 days of composting and, therefore, may be used a higher number of times. However, it should not be used when the main purpose is to produce an organic fertilizer.