Scottish Sea Farms doubles smolt weight at its new RAS hatchery
Thursday, December 3, 2020
The first smolts reared at Scottish Sea Farms’ new RAS hatchery were harvested and delivered to customers around the world. The smolts had an average weight of 178 g when put to sea – more than double the weight Scottish Sea Farms would expect to achieve via conventional hatchery methods – and required two months less in the marine environment to reach market size.
Fish were transferred a year ago from the £58 million hatchery at Barcaldine to the company’s Loch Nevis C farm for on-growing. The harvest marks the latest milestone in Scottish Sea Farms’ ongoing drive to increase fish welfare and survival.
Freshwater manager, Pål Tangvik, said that “thanks to its state-of-the-art recirculating aquaculture system, we now have much greater control over the key growth factors of water quality, oxygen levels, temperature, light and speed of flow. This creates a more stable environment compared to conventional flow-through hatcheries which, due to the fact they draw in freshwater from rivers or lochs, can be subject to changes in weather. We’re also able to keep each generation of fish completely separate and bio-secure, meaning we can maintain peak health throughout the freshwater cycle.”
The 17,500-m2 hatchery has the scope to produce up to 10 million smolts annually. Of the 5,200 m3 of freshwater required per day, up to 99% is recirculated, equating to a saving of over 20 times the freshwater consumption of conventional methods. This water is cleaned every 30 minutes via a complex system of filters and UV light and maintained at a constant temperature via a combination of heat pumps and heat exchangers. These use less energy than traditional kerosene boilers or electric chillers and can also recover heat from waste-water for re-use.
Scottish Sea Farms managing director, Jim Gallagher, said that “when it came to transforming our freshwater farming, it seemed only natural that we do so in the greenest way possible: from reducing our use of fossil fuels or finite resources such as freshwater to provision for our own hydro scheme. Through the technologies available to us, we’re also able to capture any waste material from the growing cycle. This is then removed by Invergordon-based waste management company, Rock Highland, which recirculates it as nutrient-rich agricultural fertilizer to aid crop development. It’s all part and parcel of our commitment to responsible, sustainable food production.”
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