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HAVBRUK2-Stort program for havbruksforskning

Nanofiltered intake water to RAS for improved health and welfare of Atlantic salmon postsmolt.

Alternative title: Nanofiltrert inntaksvann til RAS for bedret helse og velferd hos postsmolt

Awarded: NOK 2.9 mill.

In MEMBWELL, the focus is on fish health and fish welfare when AkvaFresh examines the use of nanofiltration for partial desalination of seawater as RAS intake water for postsmolt production. Partial desalination of seawater gives a different ion composition than in normal brackish water. Therefore, Nofima and Department of Chemistry at NTNU is involved in the project to perform a thorough documentation of the effect nanofiltered intake water has on water quality, fish health and fish welfare for postsmolt in RAS. The main experiment in the project has been completed. Two identical RAS at NCRA at Sunndalsøra were used in the experiment: one with nanofiltered water and one with normal brackish water, both with salinity 12 ppt?. Postsmolt were held in RAS for 12 weeks. Water samples for analysis of ion composition were taken every week throughout the RAS period. The RAS tank water was replaced with flowthrough seawater, where the postsmolt were held for three weeks to examine differences between the parallels related to this transition. The main sampling for analysis of fish health and fish welfare was at the beginning and end of the RAS period, and after the seawater period. Samples and results from the experiment are being analyzed. So far, the results show that the use of nanofiltered watered in RAS does not have a negative effect on fish health or fish welfare for postsmolt. An exciting result is an increased growth for fish in nanofiltered water compared to normal brackish water. There was no significant difference in concentration of the blood ions chlorine, sodium and magnesium for the fish in the two parallels. Welfare score of external morphological damage showed no difference between the parallels, and the severity was low. As expected, the content of divalent ions, as calcium, magnesium and sulfate, is lower in nanofiltered water than in normal brackish water. More samples will be analyzed and cause and effect relationships for results that differ between the two parallels will be explored.

Innovasjonen er å benytte membranteknologi til å kontrollere vannkvaliteten i inntaksvann til RAS (resirkulerende akvakultursystemer) for produksjon av postsmolt av atlanterhavslaks (Salmo Salar). Spesielt rettes fokus mot reduksjon av sulfat for redusert risiko for utvikling av H2S. Oppdrettsbransjen har det siste året hatt store tap som følge av massedødelighet i RAS med brakkvann, hvor H2S antas å være årsaken. Hovedfokus i prosjektgjennomføringen er å dokumentere effekten av nanofiltrert vann på vannkvaliteten i RAS og på helse og velferd til postsmolt.

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HAVBRUK2-Stort program for havbruksforskning