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HAVBRUK2-Stort program for havbruksforskning

DypDom: Nedsenket merd med luftkuppel for lakseoppdrett

Alternative title: DeepDome: Submerged cage with an air-dome for salmon farming

Awarded: NOK 9.0 mill.

Project Number:

296157

Project Period:

2019 - 2022

Location:

Salmon that swim deeper is infested less lice. Submergence of the cage will force the salmon to swim deeper but deprives the fish of the opportunity to refill the swim bladder. The project is investigating whether the salmon can be offered air in a submerged dome instead. Submergence of three cages to moderate depth was done at the Institute of Marine Research's sea facility from transfer in June 2019 to slaughter in summer 2020, while a new group is produced submerged from June 2021 to June 2022. Camera, echo sounder, environmental probes, fish samplings are used to document behavior, swim bladder filling and welfare. Individual coping is periodically examined with individual tags that log depth, activity and environment. Acute operational challenges are documented. The results so far are that the salmon manages to refill the swim bladder at a depth of 15 m, it maintained buoyancy and the swimming behavior was normal. However, growth was reduced due to the colder temperatures of the depths through summer and autumn and poor oxygen conditions in winter. Both fish groups had reduced welfare scores at times, but with poorer scores on the fish in the deep and less convalescence. Increased mortality was recorded because of Tenacibaculum outbreaks with associated bacteria. In a parallel Phd experiment, it was observed that conditioning to the air dome at the freshwater stage gave an increased frequency of dome use after seawater transfer. In associated master's thesis, different air heights were tested for frequency of use and welfare conditions, and in another, variation of dome use was studied throughout the day and season. Basic surface activity has been studied in detail and shows higher activity in small fish than large fish and variations in circadian patterns throughout the year. Data from individual tags for heart rate and swimming direction have been obtained, published for the control group, while data for the submerged group are being analyzed for publication. Commercially, testing of medium-sized fish from transfer to slaughter has been carried out in several cages and variable long periods with good results. In parallel, commercial design of dome cages (Atlantis and Nautilus) has been further developed and new products such as valve buoy, control bottle on cage, electrical power buoy and barge with waterborne feeding have been developed. The ongoing phase of the project investigates whether submerged salmon with an air dome as access for swim bladder filling can achieve equal growth and welfare throughout an entire production cycle given the best possible environmental conditions (temperature and oxygen) through active positioning of cage depths. In parallel, the effect of more extreme depth is tested in a smaller number of fish. The project has developed technology, basic knowledge of and documents the use of submerged dome cages as a method for producing salmon. This farming technology has great potential for use in the national and global salmon farming industry.

Laks som svømmer dypere får mindre lus. Nedsenkning av merden vil tvinge laksen dypt, men frarøver den mulighet til å etterfylle svømmeblæren. Muligens kan laksen tilbys luft i en nedsenket kuppel i stedet. Tidligere forsøk indikerer at liten laks kan bruke en kuppel for etterfylling i flere måneder. I pilottest med stor fisk taklet derimot ikke alle laksene forholdene. Overflateareal i en kuppeldiameter på 3 m og 10 cm lufthøyde var tilstrekkelig for 30 000 laks og fisken benyttet kuppelen mer over tid. Det antas at laks som lærer å bruke kuppel som liten fortsetter bruken som stor. Før innovative luftkuppelmerder brukes i kommersiell skala må det vises at laks kan produseres til slaktestørrelse med normal atferd, vekst og god velferd i oversiktlig mellomskala oppdrett. Effekter av potensielle driftsforstyrrelser må utredes, eksempelvis lufttom kuppel, tilpasning og trivsel må undersøkes. Enkeltindividers atferd og velferd må utredes. Til sist må det fremskaffes vitenskapelig dokumentasjon på at prinsippet fungerer i kommersiell produksjon med tilpasset teknologi. FoU-utfordringene løses ved å gjøre kontrollerbare forsøk med produksjon av laks nedsenket hele produksjonssykluser på moderat og ekstremt dyp. Gjennomføring vil foregå på Havforskningsinstituttets sjøanlegg. Kamera, ekkolodd, miljømålere, uttak vil dokumentere atferd, svømmeblærefylling og velferd. Individuell mestring vil undersøkes med individmerker som logger dyp, aktivitet og miljø. Akutte driftsmessige utfordringer vil dokumenteres. Parallelt vil kommersielt design av kuppelmerder videreutvikles. Uttesting med fisk over måneder vil foretas hos kommersiell oppdretter og etterfølges av produksjon fra utsett til slakt i 3 kommersielle kuppelmerder sammenlignet med normale merder. Prosjektet vil utvikle teknologi og dokumentere bruk av nedsenket kuppelmerd som metode for produksjon av laks, som vil ha et stort potensial for anvendelse i den nasjonale og globale næringen for oppdrett av laks.

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HAVBRUK2-Stort program for havbruksforskning