26 JUNE 2016 • WORLD AQUACULTURE • WWW.WAS.ORG failure of many RAS projects. Suitable sites should provide constant access to high-quality water as well as a lowcost means of treating and discharging effluent. The water requirements of a fish farm are quite different from that of almost any other activity. Conventional production wells are rarely pumped on a continuous 24/7, 365 basis. Those that are typically suffer from reductions in output over time due to accelerated fouling, which requires regular and costly maintenance and rehabilitation. A reduction in water exchange can lead to nitrate and metal accumulation, alter other chemical parameters and destabilize production. Sustaining adequate water exchange is also typically critical to maintaining stable temperatures for warmwater and coldwater species and must be carefully considered as part of siting, design and operational plans. Emerging though still sparse research suggests that maximum safe nitrate levels of 75 ppm (as N) should be applied as a design parameter to avoid negative respiratory and/ or immunological effects. Redundant sources of high-quality water, in excess of base design requirements, should be built into the development plan. 2. Achieving and Managing Production Capacity. The failure to achieve production targets is unquestionably the most frequent early problem faced by RAS projects. These facilities have high fixed costs that are largely time based and independent of biomass production. Delays in reaching breakeven or interruptions in supply can be very expensive and disruptive to customer relationships. Many issues contribute – siting, feed and fingerling quality, fish health, water quality, and operator skill typically play a role – but insufficient (or unbalanced) capacity of the filtration system is arguably the most frequent challenge encountered. Sub-optimum or variable water quality often leads to fish health problems and slower-than-target growth rates. Underfeeding, to reduce pressure on an overloaded filtration system, reduces output and increases unit production costs. Optimization of the relationship between filtration capacity, tank size, fish growth rates and grading requirements must be built into the planning process. The larger the harvest weight the greater the need for optimization of this factor. Professionally designed, site-built projects have tended to fare somewhat better but generally require a pilot phase that identifies problems, not all of which are necessarily addressed during scale-up. Scale-up of site-built facilities usually has the unintended effect of making small problems larger and often results in a protracted debugging process. Projects that rely on prefabricated systems have tended to be value-engineered to reduce capital costs to make them marketable at a profit by the manufacturer, but often at the expense of flexibility, reliability and capacity. Because pre-fabricated systems typically rely on numerous smaller units, correcting deficiencies tends to require redundant modifications, making these costly to rectify. 3. Management and Staffing. Successfully operating RAS systems requires specialized knowledge across many disciplines. A successful team will need mechanical and electronic skills, a strong working knowledge of water chemistry, fish nutrition and health management, to name a few. In my experience, building a team capable of effectively managing across this range of disciplines is one of the most challenging aspects of establishing a successful operation. While academic programs in aquaculture can help build a foundation, fish farmers are “made” though experience and it takes a many years to acquire sufficient experience to address risks and manage effectively. Surgeon Atul Gawande explains in his book The Checklist Manifesto that many disciplines have become too complex to manage informally and RAS is a case in point of what Gawande writes about. As such, it is best managed through a combination of highly structured checklists or standard operating procedures to minimize the frequency of avoidable errors and a culture of openness and collaboration to address unforeseen challenges. Our US production manager is fond of saying “It’s not about the fish, it’s about the people.” Until there are doctoral programs in RAS management, the development of highly capable managers will remain a major challenge. 4. Product Quality. Warmwater RAS typically operate with limited water exchange to conserve heat. As a result, they encourage the growth of bacteria that produce off-flavor compounds (primarily MIB and geosmin) that can rapidly bioaccumulate in fish tissues. These compounds can be detected by consumers at concentration as low as a few parts per billion. A muddy or musty flavor is the fastest way to lose customers. Protocols to ensure a constantly clean flavor – particularly for species with high fat levels that stubbornly retain these compounds – is not a trivial problem and should be built into the infrastructure and production plan from the outset. Testing to determine the time and system requirements to archive undetectable levels of off-flavor compounds is an essential requirement for success. 5. Selling Profitably. After reaching the stage of having a reliable output of marketable product, developing profitable markets is the next key requirement for success. Americans consume only about 10 percent as much fish as meat, and of the fish we do eat, consumption is dominated by tuna, salmon, cod, catfish and tilapia. This leaves less than one pound per capita for the hundreds of other species that share this corner of the market. Because more than 90 percent of the seafood that Americans consume is imported, primarily from countries with low production and processing costs, prices are competitive. For this reason, virtually all domestic RAS producers sell to specialty live markets. While live markets reward suppliers with a premium for products that can survive the challenges of transport, distribution and holding, this sector is fully supplied because it is the only viable market for most domestic producers. Adding to this, the Asian Checklists are an essential tool to ensure conformity with operational standards.
RkJQdWJsaXNoZXIy MjExNDY=