Antifouling and net cleaning
Foul play Biofouling is a problem, but there are many alternative solutions
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IOFOULING is a problem for ship operators, fish farmers and anyone else who relies on man-made structures in the sea. It can also lead to the spread of invasive species around the world, with harmful effects for the local ecosystem. An interna�onal ini�a�ve, the GloFouling Partnership Project, aims to build capacity in developing countries for implemen�ng the Interna�onal Mari�me Organisa�on Biofouling ini�a�ve and to help prevent invasive species hitching a ride on vessels. The project states: “Biofouling of cages and nets in finfish aquaculture is a significant opera�onal problem to the sector, resul�ng in the restric�on of water exchange that may adversely affect fish health by the reduc�on in dissolved oxygen and the accumula�on of metabolic ammonia. Biofouling is of further concern because it significantly decreases cage flota�on, increases structural fa�gue and cage deforma�on, and may act as a reservoir for pathogens.” Net cleaning is a regular chore for aquaculture businesses. Fortunately, there is a range of solu�ons on the market to help them deal with it. One example is the Yanmar net cleaner offered by Osterbo, which uses a high water flow with just six nozzles. Osterbo says the Yanmar robo�c cleaner is easy for farm staff to maintain and has good fuel economy. The AutoBoss, distributed by Trimara Services, is a “smart” machine that quickly covers the net surface using a flexible range of operator-set washing cycles. Situated in a compact, fully self-contained floa�ng pontoon, the machine runs close to the net surface using hydraulically driven thrusters, minimising the loss of high-pressure water
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while maximising cleaning power and efficiency. The StealthCleaner from Norwegian based Ocein AS was designed in collabora�on with remotely operated vehicle specialist Kystdesign. Ocein describes the electrically powered cleaner as “probably the most efficient and gentle net cleaner on the market, combining a large volume of water with low pressure to reduce wear and tear of the net.” Net cleaning equipment that uses water at high pressure requires a reliable pump. For example, NLB’s 225 and 325 series pump systems are designed for the kind of tough environments in which fish farmers typically operate, with durability and ease of maintenance a priority. And when it’s appropriate to clean nets by taking them out of the water – at the end of a produc�on cycle, for instance – then specialist business NetKem has a number of solu�ons, including the company’s giant universal netwasher, which operates on adjustable programmes and is available in sizes from 9m³ to 70m³. Of course, reducing fouling in the first place helps cut the �me and cost required for cleaning. Net and cage suppliers have been developing materials that resist biofouling, such as Garware’s V2 composite yarn, which is combined with extruded copper. Meanwhile, scien�sts at the University of New Hampshire have found that Ectopleura, a jellyfish-like genus or organisms, which are a menace to oyster farms in the state, are deterred from a�aching to structures where there is a surface texture and no biofilm – and they don’t like red light. FF
Net “ cleaning is
a regular chore for aquaculture businesses
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From the top: The AutoBoss washing automa�cally; The AutoBoss being li�ed into a pen for washing; NetKem giant netwasher; The StealthCleaner from Ocein AS
www.fishfarmermagazine.com
07/02/2022 14:21:36
