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1SINTEF Fisheries and Aquaculture
How to prevent escapes...?
Arne FredheimSINTEF Fisheries and Aquaculture
2SINTEF Fisheries and Aquaculture
How to prevent escapes...?Rough classification of causes
OperationalChanging of nets
Human errorError in attachment
Technical failureFatigue, wrong dimensions
Design failureWrong method, error in weather dataUnderstanding of all implications
3SINTEF Fisheries and Aquaculture
How to prevent escapes...?The simple complex construction
More complex to analyze than rigid ships and offshore construction
More fragile – strength, wear and tearLess tan 1% of the cost
4SINTEF Fisheries and Aquaculture
How to prevent escapes...?Need for volume - a size game
Increasingly larger farmsCircumference 60, 90, 120m →160m500 000 fish → 1000 tons in one single cage5000 tons at one location – is there a limit?Volume and surface
Production versus spaceOne salmon farm equivalent to 200 000 sheepLand-based on-growing not an option
5SINTEF Fisheries and Aquaculture
How to prevent escapes...?What you see...
6SINTEF Fisheries and Aquaculture
What you don’t see...
7SINTEF Fisheries and Aquaculture
How to prevent escapes...?
Example net cageIncreased size of nets - more powerful cranesNet not cleaned for bio-foulingPulling at wrong rope
To much force introduce local high tension in netting and tearingSolution:
Safety pinCrane operation – instructionDesign of net cageLife time design philosophy
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8SINTEF Fisheries and Aquaculture
How to prevent escapes...?
Example cage systemComplex mooring
many componentsDependent on one single componentOne mooring slips/break
Progressive break down and complete system failureSolution:
Test of anchorIncreased dimensionDesign against progressive break down
9SINTEF Fisheries and Aquaculture
Official technical requirements- Motivation and the system
Escape of fish the larges environmental problem of fish farming in NorwayOfficial regulations describing the system - NYTEK
NYTEK point to NS 9415 “Marine fish farms Requirements for design, dimensioning, production and operation”
Applies to: Floater, net cage, mooring system and feed barge
Classification of all aquaculture locations/siteswind, current and waves
Product certification of all new equipmentApproved according to requirements in NS 9415Control of production
Proof of capability for existing equipment (2006 -2012)
10SINTEF Fisheries and Aquaculture
Official technical requirements- Further development
Revision 2006/2007Preventing escapes – focus on
ProbabilityConsequence
Total risk level
Size limits?
International standard organization (ISO)Application process startedWorking committee 2007Increased international focusImplications for open ocean fish farming constructions?
11SINTEF Fisheries and Aquaculture
How to prevent escapes...?Approach to solution
System designLife cycle approach
ChallengesUnderstand all processes and implicationsOperational and biological criteria a natural part of designDesign technology that are human proof
Attitude and understandingInformation and trainingTechnical improvementsDevelop standards and guidelines for design
