Acronym NA
Category
Aquaculture
Title Evaluering av metoder for badebehandling mot lakselus i stormerd: Fase 1 - Evaluation of methods for bathing treatment against salmon lice in storm cages: Phase 1 Programme National Programme
Instrument (FP6)
Contact Type (FP7)
Strand (Interreg)
NA
Theme (FP7)
Activity Area (FP6)
Regional Area (Interreg)
Action (COST)
NA
Specific Programme (FP7)
NA
Funding source National Coordinator Arve Nilsen Coordinator email arve.nilsen@vetinst.no
Coordinator institution
NVI - Norwegian Veterinary Institute (Norway)
Institutions involved
IMR - Institute of Marine Research (Norway) ,
SINTEF - SINTEF (Norway) ,
Start year 2008 End year 2008 Funding (€) € NA Website https://www.fhf.no/prosjekter/prosjektbasen/900084/ Summary The aim of the project was to describe and evaluate the cage environment, drug dose and fishing behaviour bathing treatment against salmon lice (Lepeophteirus salmonis) in large cage units (157-meter circumference). The study was planned to include the use of both skirts and solid tarpaulins. In the autumn of 2008, 2 field trials were carried out, one in Sør-Trøndelag and one in Hordaland. The fish behavior and the most important environmental parameters were registered. In the first study, the dosage of the bath agent was evaluated using synthetically produced DNA molecules as trace elements, and the results were compared with direct measurements of the active substance deltamethrin. Both methods proved large variations in drug concentration horizontally in the cage and a decrease in concentration with time and depth. Registration of behavior showed in study 1 that there was an increase in surface activity after the addition of medicine, but at the same time it seemed that most of the fish in the cage swam under the skirt edge (down to 15 - 20 meters deep). In study 2, we found that the fish stayed evenly distributed from 0 to 25 meters before and after placement of the skirts. When drug was added, the salmon swam away from the treatment volume and was standing under the edge of the skirts (deeper than 15 meters). When the skirts were removed and fresh water came into the upper part of the cage the salmons swam more homogeneously in the water column again. Registration of environmental parameters showed large variations in oxygen values, with single measurements up to 250% saturation in study 1 and down to 50% saturation in study 2. The current velocity both outside and inside the cages was low in both studies. The studies showed several challenges with existing practices for bath treatment using skirts, and pointed out the following areas as particularly important: horizontal skew of drug, rapid dilution of drug in time and depth, the fish fled away from the drug if given the opportunity and equipment for oxygen addition and oxygen monitoring provided too little opportunity to correct for oversaturation or undersaturation of oxygen during treatment.
Keywords
Cage aquaculture;
Fish;
Open sea aquaculture;
Salmon;
Parasite;
Marine Region
41
Norwegian Sea (27.IIa)
13
Northern North Sea (27.IVa)
2
Marine Region Map
