Prediction of survival rate in European white fish (Coregonus lavaretus) fry on three different feeding regimes.

摘要

During the early stages of white fish, survival rate is a very effective parameter on future fry's sustainability, especially when they are going to be released into the natural habitat for restocking. The aim of this study is to define relationships between morphological and functional traits and the survival rate of the European white fish fry (Coregonus lavaretus) when they were fed with different feeding regimes. One hundred and fifty newly hatched white fish fry stocked into nine rearing cages, under a flow-through rearing system, were distributed randomly in a natural pond, and nourished for twelve weeks with three kinds of food, the rotifer (Brachionus plicatilis), a compound Salmonidae commercial diet and a mixture of 50% of each, all treated in triplicates. The backward method of regression procedure was used for statistical analysis. Combinations of independent variables to multiple linear regression models were based on the changes in the R2 statistics and the F-value were produced by adding or deleting an independent variable. The five variable combinations (individual weight, length, total weight gain, total feeding rate, and feed efficiency) predicted the larval survival rate in multiple linear regression models and supported by partial correlation. This study revealed that; length and weight bear negative signs whenever they appear in these statistical relations. Also the higher the feeding rate, the survival rate increases accordingly regardless of the treatment effect. Finally, in mixed feed, predicting the survival rate is easier and more practical since the only parameters remaining in the equation are the length and weight of the fry. Perhaps this finding is because of the fact that the co feeding (rotifer and compound) can better satisfy the nutritional needs of these larvae than each feed alone.