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One of the possibilities for aquaculture that has been in the back of my mind is the notion of free range.

While I thought this was a bit far fetched I’m finding more and more reference to this possibility and development of dovetailing technologies. These include; SINTEF use of cybernetics to research remotely operated freerange fishfarming, MIT use of sound to train fish to feed, Tagging and virtual fencing(cattle) development by CSIRO and the constant development of automated underwater and airborn vehicles.

While this possibility may seem futuristic today, the idea  of capturing 150 ton of tuna at the head of the Great Australian Bight and towing it to Port Lincoln for grow out is to my mind still impressive.

While the technology is not quite there it all seems to be pointing in the right direction. This possibility would need to be carefully scrutinised for innovation quality as at first glance it doesn’t appear to cover off on immitation and uncertainty criteria, but in an increasingly crowded world seeking quality organic foods these criteria may be easily met by developing technologies.

This concept also poses some interesting dilemas for our legislators although it must be said we have been droving cattle across the country for the best part of 2 centuries.

The FAO has published a report on cage aquaculture.

The report aims to assess the current situation and the future prospects of cage aquaculture around the globe. It is organized into nine chapters including a global overview and eight reviews covering various regions.

The report provides detailed information on the current situation; outlines the major regional issues and challenges; and highlights specific technical, environmental, socio-economic and marketing issues that cage aquaculture faces and/or needs to address in the future.

The global overview discusses trends in cage aquaculture based on the most recent and complete data available; summarizes the information on cultured species, culture systems and culture environments; and explores the way forward for cage aquaculture.

The report may be accessed here.

The World Intellectual Property Organisation has published a patent application and search report for a submersible rotatable cage for fish farming. The application was submitted by Canadian company  Open Ocean Systems Inc. 

The cage comprises a central axle, a buoyant structure positioned about the central axle, and a netting attached to the buoyant structure.

The buoyant structure rotates about the central axle while the cage is in a submerged position. The cage can form part of a system, which includes a net cleaning apparatus, a tethering mechanism and sweep net, that forms the basis for underwater fish farming.

The patent application and search report may be reviewed via the free WIPO patent search capability.

In the most common setup for fish farming plants, a number of floating net cages are anchored close to shore using buoys and weights to stabilize the cages in the water.

An optimal installation for fish farms of this sort is in sheltered waters such as bays and fjords and these setups often comprise support frames with gangways for operational purposes, such as maintenance and feeding.

Surface cages, however, are sensitive to severe weather conditions, such as high winds, waves and ice, which can be a serious threat in northern areas.

Submersible cages have been suggested and tested. However, these types of cages have not become commercially feasible due to problems with stability, handling and cost.  The present invention claims to overcome these limitations.

I spoke with Ian McRobert today about his Semi Intensive Floating Tank System (SIFTS) technology. The interview includes links to videos and pictures of his waste minimising aquaculture systems.

Ian and his team are using low pressure air in very unconventional ways to generate some significant advantages, especially in promoting a clean environment for fish growth and through innovative approaches to waste handling.

This is a picture of a small scale trial of the SIFTS system in Fremantle Harbour in Western Australia. The trial is a breakthrough in that it has gained the support of the Fisheries Department, the Environmental Protection Agency and the Port Authority.

Finfish: Ian, you have been able to achieve some some impressive stocking densities with your SIFTS approach. Can you share with us your present metrics?

McRobert: Yes Andrew, we have experienced exceptional carrying capacities with our system. Our experience is that fish can be cultured at stocking densities above eighty kilos per cubic metre without the need to resort to pure oxygen or sophisticated recirculating aquaculture system (RAS) equipment.

Finfish: How do you achieve this Ian?

McRobert: Our SIFTS waste extraction system efficiently removes almost all of the solid waste - in fact up to 95% of all faecal matter is extracted quickly. Our objective is to minimise the opportunity for material to suspend or dissolve in the water column.

Finfish: Ian, you have secured environmental approval and the endorsement of the Fremantle Port Authority to trial SIFTS?

McRobert: With its waste extraction capabilities, SIFTS is able to avoid some of the biggest challenges facing aquaculture like the environmental effects caused by some cage operations conducted in nearshore areas.

Finfish: What other techniques do you use to maintain a clean growing environment for your fish, Ian?

McRobert: we use a patented liner technology that allows us to easily and thoroughly clean the tank to promote as pristine a growing environment for our fish as possible. The liner also gives us major benefits in stress free fish handling techniques. You can check this out easily by reviewing the videos on our Website.

I have included a link to the fish handling videos here.

Finfish: Thank you Ian.

McRobert: Thank you Andrew. Here are a few pictures of our system in Fremantle Harbour to allow Finfish readers to see what we are up to.

If you would like to find out more about the SIFTS approach, please visit the McRobert Aquaculture website.

Neil Sims, an ex-pat Australian, is the president and co-founder of Kona Blue Water Farms. The farms, situated off Hawaii, are stocked with ‘Kona Kampachi’ or yellowtail and Sims is embracing the need for sustainable aquaculture innovations. To date, Sims has assisted in the modification of submersible cages to make them ‘flippable’ and therefore much easier to clean in addition to trialling various food sources, some with very positive results.

If you would like to view the full article, please click here.

In considering the future of aquaculture the work of Pål Lader from SINTEF Fisheries and Aquaculture (Norway) is a must read.

In an article entitled 2020: An Aquaculture Odyssey in Gemini Magazine Pål sketches out what the future of the aquaculture industry could look like.

Free-range farmed fish. Sea cages that sail off and deliver their fish by themselves. Large autonomous fish farms that float unmoored in the sea. This could be the aquaculture of the future, the article states in a well argued scenario of what the future could look like.

When not casting his mind forward to design the aquaculture systems of the future Pål is a researcher for Norwegian Science Agency SINTEF with expertise in understanding the load bearing capacity of various types of aquaculture structures.