Prevention of Saprolegnia on Rainbow trout eggs

Abstract

In spring 2004 pre-eyed eggs of rainbow trout (Oncorhynchus mykiss) were treated against saprolegniasis with Ibiza salt, hydrogen peroxide, and BioCare at different concentrations and exposure durations twice a week. The fungistatic effects, hatching rates, and cripple rates were compared to those of negative control, which received no treatment, and to those of positive control, which was treated with Pyceze, currently considered the best treatment option against saprolegniasis. No treatments were better than Pyceze. However, hydrogen peroxide treatments were statistically as good as Pyceze with the exception of fungal infection which was higher for the hydrogen peroxide treatments. Ibiza salt and BioCare can not be recommended as Ibiza salt treatments were no better than no treatments at all and BioCare seemed to be toxic to the eggs. Fungus infecting salmon eggs was identified to be Saprolegnia sp. Although not identified it was assumed that it was this same species that also infected the rainbow trout eggs. The number of fungal spores in the intake water decreased during the treatment period but there was no connection between number of spores and infection of the eggs.

Date of Award	2004
Original language	English
Awarding Institution	Náttúruvísindadeildin - Faculty of Science and Technology
Supervisor	Eyðfinn Magnussen (Supervisor) & Peter Østergaard (Supervisor)