Seaweed Farming

The principles of modern Seaweed farming are outlined below :-

Specimens are collected prior to their spawning and placed into tanks – as a hatchery – so that when the algae spores these are provided with a substrate on which to settle. The tanks are provided with forced air, and filtered seawater. When the small plants have developed into recognisable buds, the line on which the spores have settled is wound onto a supporting rope, which is then transferred to the growing site. In the case of the Gigha Halibut project, this is using the hatchery tanks which were previously used for fry for the fish farms. This is not strictly necessary as the ropes could be transferred directly into the sea to be grown.

The advantages of tank grown seed rope is that the species can be exactly determined, and no unwanted species will be on the ropes. The only other advantage is that if the seaweed is grown in a tank – and thus farmed – it can come under the jurisdiction of “Organic Farming” for human consumption, and get certification as such, whereas wild seaweed cannot. Certification is applied only to the processing methods.

The disadvantages are that firstly the lab costs are quite substantial, with the academics claiming it to be a difficult and precise process, in fact the process is very simple and can be done at home with simple fish tank apparatus, it requires the same conditions as fish species kept as domestic “pets”.
In the case of the Otter Ferry SeaFish experiment, for growing on the seaweed must be provided with both nutrients – in the form of seawater, and oxygenation in the form of forced air. The proprietors of the hatchery have their own private hydro-electric plant to supply power for pumps etc.

At SeaVeg we have an alternative system, whereby the ropes can be seeded directly in the sea by small scale growers, and then after “picking” off unwanted species, can be placed directly on the growing site – in the wild for growing on.

In the USA the industry is quite advanced now compared to 10 years ago :-

Handbook for Seaweed Culture in New England by Sarah Redmond

“Wild Farming” using seeded ropes :- The Kelp Farm by Sarah Redmond

And compare to the manual methods described here :-
Seaweed farming in small islands

So where is the real application of “Laboratory Farmed Seaweed in the UK ?” – its on the fish farms, as Porphyra can be used to feed the fish and as stated by Sarah Redmond this can provide up to 80% of the feed needed for some species of finfish. For human consumption the laboratory is just not needed, any sailor will know that various species will attach themselves to mooring lines, causing extra weight on the lines, and older lines attract more algae. To farm seaweed in the wild in Scotland all that is needed is a suitable growing site, and drying and processing facilities, the ropes can be seeded in the wild, and attended by boat or from the shore. Permissions are needed from SNH, Marine Scotland A ND Crown Estates. The general opinion exressed by Food Safety is that there is a “Dilution Effect” of the sea for industrial pollutants and sewage run off, and Seaweed is very good at mopping up pollutants in the sea including heavy metals and isotopes, but I personally would not want to eat seaweed from the rocks by the sewage pipes at Seafield, or North Berwick, or from the bay at Torness, or from radioactive Dalgety Bay.

All of our Sea Vegetables are wild harvested in a sustainable manner – as they have been for generations, from the clean waters off North West Donegal.

Threats to our Marine Environment
Farming Kelp for Biofuels Project
Whilst using Seaweed as a potential biofuel source might seem initially to be a good idea, listeen to what the speaker is saying, next stage 50m x 50m areas, and then vast expanses of marine monoculture, plunging our seabed into darkness, and extinguishing all marine life beneath them. The use of seeded ropes to grow seaweed is indeed a good idea, but putting control of our seas into the hands of Oil companies is NOT. Rope seeded seaweed cultivation should be used to enhance local biodiversity, by providing improved habitat for other species, which means growing a diversity of seaweed, on a smaller scale, which can then be used to improve wild fish stocks, and associated industry. You can be sure that if Oil companies are allowed to farm seaweed on a massive scale, then they will put poisons into the sea to kill off any pests or parasites which will inevitably end up in the food chain.