Arne Fredheim SINTEF Fisheries and Aquaculture

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

0

0,5

1

1,5

2

0 0,1 0,2 0,3 0,4 0,5

Løftehastighet [m/s]

Van

nmot

stan

d [t

onn]

d

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