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Prosjektnummer: 900481
Status: Avsluttet
Startdato: 01.01.2010
Sluttdato: 31.12.2012

Technologies, systems and operational procedures for high-level accuracy in biomass control in large cages (EXACTUS)

Prosjektet skulle bidra med grunnleggende kunnskap om muligheter og teknologier for mest mulig nøyaktig måling og kontroll med biomasse og antall fisk i merder. Totalt sett ble ikke målet nådd da dette fremdeles er en utfordring for næringen.

I regi av Exactus ble det gjennomført en studie hvor data fra 240 slaktede laksemerder ble undersøkt for avvik mellom innmeldt (forventet) antall, total biomasse og snittvekt og reelle tall fra slaktelinjen. Totalt sett var innmeldt antall nesten identisk med slaktet antall. Det samme gjaldt for total biomasse. Enkeltmerder hadde imidlertid betydelig avvik og avvikene fordelte seg jevnt på begge sider av null. Dette tyder på at presisjonen i beholdningsestimering er lav, men at det ikke er systematiske feil som trekker i en bestemt retning.
Kombinasjon av målinger og biomasse-estimering
Det ble i prosjektet utviklet en modell som estimerer biomasse, og oppdaterer estimatene basert på ulike registreringer som gjøres i anlegget (utfôret mengde, temperatur, osv.). Modellen er ikke ferdig utviklet.
Studier i prosjektet viste klart at det er utfordrende både å få nok fisk til å svømme gjennom målerammer, og å få et representativt utvalg blant annet fordi fisken fordeler seg ujevnt i merden, større fisk ser ut til å stå dypere, m.m. Dette bekrefter erfaringer fra oppdrettere.
Undersøkelsene i Exactus viser at tiltakene for bedre biomassekontroll i første rekke bør konsentreres om å optimalisere bruken av de beste målesystemene som er tilgjengelig i dag. Måleteknologien ser ut til å gi mulighet for langt mer presise målinger enn den presisjonen som oppnås for enkeltmerder med dagens biomassekontroll. Statistikk som er innhentet og vurdert i Exactus viste, for slakt av 134 608 tonn fisk i Midt-Norge for perioden juli 2009 til juni 2010, et avvik på antall på 0,03 % og 0,45 % avvik på biomasse i forhold til forventet.

Telling av fisk ved splitting og sortering hadde ikke nevneverdig betydning for antallskontroll. Ved høy akkumulert dødelighet slaktes det mer fisk enn forventet, noe som tyder på overestimering av dødelighet når denne er høy.

Ytterligere informasjon
Resultater og rapporter finnes her: https://www.sintef.no/exactus
Insufficient biomass control has been a recurring issue for Norwegian aquaculture during the last decade (www.tekmar.no). The concept “biomass control” covers the estimation of biomass through measurements, instrumentation (biomass monitoring), but also the operations involved in the process regarding control of planning the production at each site according to the maximal carrying capacity, splitting of cages, grading, and management of harvest and of advance sales.

The issue of biomass control has been prevailing over the past 20 years as units in commercial salmon farming have become larger and larger. Modern cages may be 50 m in diameter, 40 m deep with highly variable effective volumes (related to current deformation) and containing up to 1200 tons of fish (Lader et al. 2008). The modern farms thus consist of a vast, ever changing volume and a huge number of individual fish, constantly swimming. This constitutes an enormous challenge with respect to biomass monitoring. Accurate estimation of available biomass and fish count, as well as sizes and weights in each cage is crucial through the whole production cycle. Many factors depend on it, such as dosage of feed and medicaments, better fish welfare with respect to population density and oxygen flow, an accurate basis for advance sales, estimation of site ecology and thus the general profitability of fish farms.

Lack of precision in measurements and accounting of numbers of salmon, average weight and size distribution, is a costly game of guesswork for the industry. A recent impact study, The economical consequences of insufficient biomass control in sea-cage aquaculture, gives an estimate of the total potential losses due to insufficient control on a 900 000 ton yearly production and a typical ±5% error on biomass. The numbers then add up to about NOK 1 billion each year only in suboptimal sales and suboptimal feeding (Aarhus, in prep.). There is no apparent evidence that the worldwide losses should be of less proportions. Biomass estimation using the currently available methods functions reasonably well in smaller cages, but as the cages have grown bigger, the precision of today’s solutions has become less accurate. Marine Harvest Norway presents errors of 5-10 % to be normal (Ragnar Nordtvedt pers. com.).

The reasons for the imprecise estimates of the state-of-the-art systems are not fully understood and will be subject to investigation. The dynamics of fish density in cages are unknown, e.g. whether different size fractions utilize different space domains in the cages. When it comes to technology, there is a need for a thorough basis of knowledge for both operational methods and software. The core technology for biomass estimation has not seen any significant changes during the last 10-15 years, and a screening of possible new approaches regarding measurement principles should be done to meet the challenge. Significant differences in accuracy occur with the use of similar equipment at different sites. This apparently random fluctuation necessitates a proper examination regarding protocols for efficient operation of equipment and a well thought through man-machine-interaction (MMI).

A thoroughly communicated, fully transparent process lead to an open workshop on 23rd of June 2009 where industry and governmental parties were invited to influence the project focus (funded by FHF (FHF-900271)).
To obtain new knowledge and a technological basis for future biomass measurement systems with a potential to approach the desired accuracy, reliability and operational requirements in large cage aquaculture systems.

1. To develop and evaluate basic technologies for biomass measurement and monitoring. Assess and demonstrate the feasibility and capability of new equipment systems for biomass measurement based on the evaluated technologies.
2. To develop a theoretical basis for continuous model-based estimation on the total number and weight distribution of salmon in a cage with emphasis on establishing and validating a mathematical model representation of biomass growth.
3. To explore the dynamics of salmon behaviour and welfare in cages to provide a theoretical foundation for more representative sampling for existing and new biomass technology.
4. To develop new knowledge on the implementation and operation of measurement instruments to maximize accuracy and repeatability in commercial aquaculture production.
Expected project impact
The industry’s vision is ±1% accuracy on salmon average weight, and ±0.1% on the number of fish in the different size classes ready for slaughter (2-3, 3-4kg etc.). The project aims to develop knowledge and demonstrate solutions which can help to make the quantum leap in biomass control from the current status of 5-10% typical error towards the industry’s vision.

For the fish farmers (Marine Harvest Norway, Salmar, Lerøy Seafood Group) EXACTUS will provide means to enhance production control with more precise feeding (BioMar and EWOS Innovation) and thus reduced production costs. The developed solutions will reduce transport-cost due to increased accuracy in planning. The most important economic benefits will be evident in sales, because the advance sales can be more accurate and reduce the expensive process of levelling when shortcomings in stock assessment have to be made up for with spot market purchases. Through increased control the Norwegian fish farmers can fulfil the expectations of the Directorate of Fisheries, increase the public standing and fortify the position as the world leader in salmon production.

The technology producers, such as VAKI, will consider the results from EXACTUS as knowledge and solutions they can develop into their own line of products and thereby strengthen their market position. Subcontractors to this industry, such as Norbit and Nexans, will be able to grow based on acquired knowledge, which in turn can evolve into new innovations for components of the advanced biomass control systems of tomorrow.

The development of better biomass control systems through the competence building project EXACTUS will enhance the position of the Norwegian aquaculture industry and may easily form the basis for further spin-offs and innovations.
Project design and implementation
The problem of measuring the total biomass in a cage consists of two elements:
1. Keeping accurate account of the number of salmon in the cage. It is considered very difficult to achieve the vision accuracy of ±0.1% in the fish count based on measurements while the fish are in the cage. The approach will thus be to do an accurate counting of the number of fish put into the cage during start-up and splitting of cages, and then keep accurate account of the number of fish taken out of the cage due to e.g. death, sickness, “leakage escapes” and sampling. Proper instrumentation, operational procedures and a functional intelligent accounting system will be needed for this purpose.

2. Measuring the weight distribution of the salmon in the cage. This needs to be done in situ with minimal disturbance to the fish. All technologies that have been developed and that seem feasible for this purpose are based upon measurements within local, limited volumes within the cage. Since the fish tend to segregate into different size categories and to gather into schools, reliable procedures are needed to obtain a representative sampling of the total fish population and/or to compensate for statistically biased samples. New knowledge on fish behaviour is needed in addition to more suitable and accurate instruments. This combined knowledge will have to be brought forward by means of new operational management guidelines.

Research activities (RA)
The four main research activities in EXACTUS addresses the needs listed above. These have been identified in close co-operation with the industry, both farmers and producers, as the most important scientific challenges for the biomass monitoring today.

The activities are:
RA 1: Instrumentation for biomass measurement
RA 2: Mathematical modelling and model-based estimation (MBE)
RA 3: Salmon behaviour, cage environment, mortality and size registrations related to representative sampling for biomass control
RA 4: Operation and management – methods, design and user interface

International co-operation
Several of the industry partners are global companies with an overview of the current status in the world aquaculture sector. One of the consortium partners, VAKI as a large Icelandic equipment producer, is looking towards Norway for scientific contributions for the future equipment innovations. The consortium composition ensures a rapid and thorough spread of knowledge, technology and methods brought forward in the project. The research partners have a well developed international network, which will be employed to provide input, such as guest lecturers at seminars at “EXACTUS DAY”. Potential candidates are scientists in the consortiums existing network such as Prof. William Howell, University of New Hampshire, USA, and Senior Scientist Dr. Timothy Stanton, Woods Hole Oceanographic Institution, USA.

Project Board
A project board is established to ensure implementation of the contract with the Research Council and FHF with respect to use of resources and deliverables. The members are:
• Ragnar Nordtvedt, Chair (Marine Harvest)
• Arnfinn Aunsmo (Salmar)
• Arve Olav Lervåg (Lerøy Midnor)
• Thorvaldur Petursson (VAKI)
• Tor Andre Giskegjerde (EWOS)
• Trygve Sigholt (BioMar)
• Gunnar Berthelsen (Nexans)
• Arild Søraunet (Norbit)
• Ulrik Ulriksen (Ocea-gruppen)
• Knut Johnsen (Fiskeridirektoratet)
• Audun Pedersen (CMR)
• Tom Kavli (SINTEF IKT)
• Frode Oppedal (IMR)
• Eystein Skjerve (NVH)
• Jo Arve Alfredsen (NTNU)
• Sverre Holm (UiO)
Dissemination of project results
A tight communication and cooperation is important to ensure that the project focus is in line with the industry needs. Two mini-seminars will be arranged annually, where results are presented and selected key challenges are addressed.

The dissemination of results will take place at www.sintef.n​o/exactus​, where also popularized information of public interest will be made available for newspapers, thematic exhibitions etc. The scientific results of this project will be published in peer-reviewed journals and presented at appropriate conferences (e.g. EAS, WAS, Research Council of Norway Havbrukskonferansen).

Results of industrial interest will be published through national and international specialist press (e.g. Teknisk Ukeblad, Gemini, Norsk Fiskeoppdrett, Fish Farming International, IntraFish). The information from the project will be presented during exhibitions like AquaNor, aquaculture industry meeting places like TEKMAR and the annual meeting of the Norwegian Providers for The fishfarm industry (NLTH).