![]() Ropes are deployed from October through January, which is a very large window of time, but we are continuously conducting trials, varying both location and depth, using both species of kelp to find optimal seeding and deployment times. Blueharvest windows trial#For the 2018/2019 season we've set a number of vertical trial ropes so that we can monitor growth at different depths throughout the season. Too little is known about the parameters for optimal growth, but given how the environment changes so much we think that we need to keep the ropes deeper the further into the season we get. During summer the sun is up 24 hours a day, never setting for 6 weeks. At 69 degress north Lofoten is north of the arctic circle, we have very little sun in the winter, and for a whole month it stays below the horizon. The rough conditons are made even worse with the radical change in temperature and light throughout the season. These factors correlate because when the tide goes in or out, the current is much stronger where the water is shallow, and that's often where you'll find Winged Kelp. Winged Kelp seems to be doing better and will grow in shallow water 5 meters deep, or even less, as long as the conditions are rough and the currents strong. It's almost impossible to find good Sugar Kelp less than 15 meters deep, and most of it is at 20 meters or deeper. The current helps push the ropes up, but usually we attach one or two floats per rope to keep them relatively high in the water, even when there is no current.Įxperts in the field will tell you that it is crucial that ropes be kept as close to the surface as possible, but in our experience, here in Lofoten seaweed seems to prefer relatively deep water. The seaweed ropes should be as close to the surface as possible, at least at the start of the season, to get as much of what little sunlight there is as possible. If the frame gets too deformed the seaweed ropes will come in contact with each other, which will quickly lead to rope tangling and loss of crop yield. They have a tendency to slacken over time, and with strong currents pulling the frame in every direction, the effect is even more pronounced. With only 2.5 tons of tension on the frame it's important to keep a close eye on it and maintain tension throughout the season, especially if the ropes are new. This is necessary both for deployment, maintenance and harvesting. This is considered a low tension, but we do it so that we can get to the frame with a boat hook and lift it up by hand from a small motorboat. The frame is placed as close to the surface as possible and tensioned with a 2.5 ton windlass. The mooring system is simple as well, and very similar to the cage mooring systems used in fish farming. The seaweed ropes are placed in parallel across the frame in 3 meter intervals. The seaweed farm is a very basic construction, it's just a floating frame, 75x75 meters. In the mean time it is extremely important that the ropes aren't allowed to dry out or be exposed to frost. The ropes are shipped in styrofoam containers each with 600 meters of rope, ready to be deployed directly. Handling is much easier though, a shipment of 5 or 6 km can easily fit in a compact van. This gives the spores time to attach to the rope without the use of glue, but it's expensive and time consuming. Eukaryo spores are sprayed on the ropes in the lab, and then kept under artificial light in special containers with circulating filtered seawater. They're much thinner than the ropes we use with Hortimare's seed, which are 17-23 mm (though 12 mm would be sufficient). The ropes are only 6 mm, which is about as small a diameter as you can get with direct seeding. In contrast, the Eukaryo spores are delivered pre-seeded on the ropes. The glue keeps the seed inside the rope for a while after it has been deployed at sea, and gives the spores time to attach themselves to fibers. The rope quickly absorbs the mixture of seawater, seed and glue, and we then run the rope through a pressing tool, which is basically just two rollers that press excess mixture out of the rope. The spores are mixed in a tub of seawater and a special glue, the ropes are then submerged in the tub, one by one. This is a very important feature, and the seeding method depends on the rope's ability to absorb a lot of water quickly. This rope is like a sponge in that it can hold a lot of water. We use a special double braided (braid on braid) 12-strand rope, with 50% polyester and a very loose braid. The spores from Hortimare are seeded directly on the rope at our land base here in Lofoten. Lofoten Blue Harvest has two suppliers of spores, Hortimare in the Netherlands, and Eukaryo at Sandhornoya south of Bodoe (in Norway). ![]()
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