Siegfried Beck is looking for buyers for his Beck Cage in Japan.
Beck, of GAATEM Consulting UG, based in Duisburg, Germany, hopes that the innovative offshore aquaculture cage he invented will be utilized for bluefin tuna, given that the species requires larger pens than those normally employed for sea bream and yellowtail. Bluefin swim very fast, and have a habit of ramming themselves into cage walls at high speed, which often kills them. Adequate space is a must for bluefin, and Beck is offering his cage as a solution.
The largest salmon farming company in the world, Marine Harvest, based in Bergen, Norway, has already bought the rights of the patented innovation for the European Atlantic. Offshore cages are seen as one answer to the sea lice infestation and pollution problems caused by Norway’s salmon farming. There is much greater movement of water in the open ocean than in enclosed waters, so feces and uneaten food do not gather on the ocean floor. Open-ocean pens are often submerged. Since sea lice mainly inhabit the surface, the fish contact them less.
Regarding cages for use in the open ocean, the icosahedron (roughly a sphere made from connected triangular pieces) and spherical polyhedron (the pattern of a soccer ball) shapes are the main styles used now. These styles are both bigger than a typical circular net pen. Smaller models are open on the inside, while larger models have a central support pillar.
The Beck Cage somewhat resembles this second style, in that it also has a central pillar. However, rather than having a nearly spherical shape, it is cylindrical and sits below the water lengthwise like a submarine. It has a central lengthwise pillar, but also has spokes that extend to the cage walls. This extra structural support allows the cage to be larger than competing cages. The 100-meter long, 16-meter diameter cylindrical Beck Cage provides a volume of more than 20,000 cubic meters.
“There are designs for offshore fish cages which are actually reinforced conventional fish cages,” Beck said. “These designs have their static strength in the periphery frame and not in the axial pipe like Beck Cage, which means the frame has to be much bigger and heavier than Beck Cage.”
Beck asserts that his cage costs as little as one-third that of such cage designs, per cubic meter.
It has other special features, such as systems to pump oxygen and feed into the cage from a support or towing vessel. Nets can be positioned along the radius inside the cage so that when the cage is rotated, fish to be harvested can be gathered to the water line easily. By adjusting the mesh size, they can also be graded for harvest, to only select those that have reached a certain size. A short net can be similarly positioned at the cage perimeter to scoop up only those dead fish that fall to the bottom of the cage.
The cage is usually kept below the surface, but can be raised up to halfway out of the water, allowing attached algae and the like (biofouling) to be bleached by sun and dried by air. This is to allow easier cleaning.
The Beck Cage also differs in that it is designed to be either anchored from a single point, in which case it acts like a boat at anchor, changing its position in an wide arc with the change of currents, or towed behind a converted container ship.
Beck envisages up to three Beck cages being pulled by one vessel. This vessel would carry feed and an onboard hatchery. When the fish are mature, Beck said, the whole farm could be towed long distances to a market country. He gives as an example the idea of raising cobia off Oman and then towing the fish, cage and all, to Japan for sale.
While Marine Harvest has picked up his idea, the Norwegian government did not. Norway is funding research into such new systems, too, spending money and granting site permits to test a few of the most promising systems. Beck’s design was not selected by the Norwegian contest. The reason given for the rejection was that the details of the design were not adequately described in the submission. (The design of the actual cage was described and drawn in detail, but the supporting ship idea was presented as a concept drawing, according to Beck.)
Beck says that the rejection is not so much due to insufficient detail, but rather because his idea is unorthodox, and therefore difficult for traditionalists to grasp.
“I am looking forward to see whether the Far East gets the point and shows interest in the Beck Cage System,” he said.
As the Beck Cage is very large, Beck suggests it for outgrowing of bluefin tuna. He hopes that the wide space of the Beck Cage, as well as its ability to be towed from hatchery areas to grow-out areas may make it suitable for this purpose. As bluefin are already moved within Japanese waters from hatchery areas to grow-out areas anyway, and this transfer is a stage where some mortality losses occur, there would seem to be potential to test his idea.
