Marine fish eggs can function as transport routes for the transfer of pathogenic micro-organisms. It is therefore quite important to have good routines for surface disinfection of eggs to maintain an effective barrier between facilities and internally within a facility. SINTEF Fisheries and Aquaculture has developed a method for disinfecting marine fish eggs based on glutaraldehyde. The method has proven to be effective against bacteria without showing any negative effects of the treatment on several marine species.
The picture on the left shows the bacterial growth on an untreated egg. The picture on the right shows a disinfected egg.
Photo: Ingrid Salvesen
Live feed production is accompanied by a significant production of micro-organisms like bacteria and ciliates, and the conditions usually favor the opportunistic and potentially most destructive bacteria. Live feed can therefore transport large amounts of bacteria to the digestive system of the fry. We are studying how the micro-flora in live feed can be regulated in an environmentally safe way based on our know-how from bacterial growth in such cultures.
Water treatment
In intensive production facilities for marine fry, a variety of methods are used to treat the water supply (filtering, UV radiation, ozone) to avoid particles and pathogenic micro-organisms.
In through-flow systems, which are the most common production units in Norway today, this requires treating a relatively large volume. The effect of this treatment, with respect to controlling the microbial environment, is limited since the water in the fry basin is continually varying in organic and bacterial load. This leads to an unstable microbial environment that supports the growth of opportunistic and detrimental bacteria.
SINTEF Fisheries and Aquaculture has therefore worked for several years to develop different methods to stabilize the fish larvae’s microbial environment.
