Location: Cool and Cold Water Aquaculture Research2020 Annual Report
Objective 1. Improve fish health, performance, and welfare in recirculating aquaculture systems. Sub-objective 1.1 Evaluate salmonids grown to market size in a semi-commercial scale freshwater RAS. a): Collaborate with NCWMAC to evaluate multiple strains of Atlantic salmon and their performance in a RAS environment. b): Assess genetic strain of steelhead (including USDA-strain rainbow trout) raised to 4kg in a RAS environment. Sub-objective 1.2 Assess environmental manipulation to reduce maturation in mixed-sex diploid Atlantic salmon. Sub-objective 1.3 Improve biological monitoring and management of salmonids in RAS through technological integration of next-generation biomonitors. Objective 2. Support land-based salmonid recirculating aquaculture systems production through increased technological and operational efficiencies and novel, supplemental revenue streams. Sub-objective 2.1 Evaluate methodologies to convert RAS waste to value-added products. 1a: Assess feasibility of new composting technologies of RAS waste solids and their capacity to generate sellable products. 1b: Assess feasibility of anaerobic digestion of RAS waste solids to generate biogas/energy. Sub-objective 2.2 Assess novel methods to improve RAS water quality, including optimized integration of membrane biological reactors. Sub-objective 2.3 Pilot and evaluate new computing technologies for RAS integration to optimize system operational efficiencies.
The domestic salmonid aquaculture industry is currently experiencing a significant departure from traditional farming practices, as evidenced by recent, substantial capital investment in large-scale land-based, closed-containment facilities utilizing water recirculation aquaculture system (RAS) technologies. While this is an encouraging evolution for U.S. aquaculture overall, this relatively new approach to raising market-sized Atlantic salmon, steelhead trout, and other economically important species is still a frontier in agriculture, remains largely untested at commercial scale, and requires significant refinement and optimization in technological, biological, and economic methods and strategies. The Conservation Fund Freshwater Institute (TCFFI), an extramural program of the USDA-ARS, has been at the forefront of RAS technology research and development for over two decades, and at present we are uniquely suited to continue serving this growing agricultural sector through focused, industry-relevant research and innovation. Our next 5-year project plan seeks to address critical areas that are necessary to support the sustainable growth of the U.S. land-based, closed-containment aquaculture industry; specifically, our objectives fall under two broad categories aimed at improving i) the biological performance of salmonids in RAS, and ii) the technical and economic efficiencies of land-based closed-containment operations. Research activities will include identifying genetic strains of Atlantic salmon and steelhead for optimal performance in RAS, assessing methods to reduce early sexual maturation and improve water quality, developing next-generation biomonitors and computing technologies to improve fish health management and RAS environmental control, and developing means for RAS producers to monetize waste streams for enhanced economic viability.
Progress towards Sub-objective 1.1 has included receiving eyed steelhead eggs of six separate varieties: i) USDA growth strain rainbow trout; ii) Troutlodge all-female diploid; iii) Troutlodge all-female triploid; iv) Riverence all-female diploid; v) Riverence all-female triploid (pressure shocked); and vi) Riverence all-female triploid (heat shocked). Additional eyed eggs from Troutlodge (all-female diploid) were also procured as “filler fish” for the growout trial, i.e. additional biomass to maintain commercial densities. These eggs have been all successfully hatched and stocked into a flow-through early-rearing system. At the time of report submission, these fish are below size for inducing smoltification; however, in the second half of 2020 we will carry out smoltification (July, 2020) of 50% of the population (excluding filler fish) and will stock our main growout RAS once mean size is approximately 150 g (October, 2020). Growout will continue until the fish are approximately 4 kg mean weight. In support of Sub-objective 1.2, we received and hatched Atlantic salmon mixed-sex diploid eggs, and stocked 2,040 salmon (50 g mean weight) into our replicated experimental-scale RAS. We did not use photoperiod manipulation to smoltify these fish, however; this decision was based on our most recent research indicating that photomanipulation does not confer long-term growth performance benefits. Also, in support of this Sub-objective we have modified existing infrastructure to install chillers in the experimental-scale RAS in order to maintain the experimental conditions for this study. At the time of report submission, salmon raised at 12 degrees Celsius averaged 140.5 g while salmon raised at 14 degrees Celsius were 150.1 g, indicating the expected growth advantage of the higher temperature treatment. Regarding early maturation, a very small number of precocious parr have been observed in the 12 degrees Celsius treatment group only, which is unexpected, and we will monitor whether this trend continues in subsequent sampling events. Progress towards Sub-objective 2.1 has included hiring an Environmental Research Engineer and beginning the process of the bench-scale anaerobic digestion study, which will be carried out during the second half of 2020. This project will evaluate RAS salmonid waste solids as a substrate for anaerobic digestion and biogas production, quantifying methane (CH4) and hydrogen sulfide (H2S) production and volatile solids through degradation of fish waste. Planned batch laboratory testing will follow the established biochemical CH4 potential protocol, utilizing an incubation shaker with biogas, CH4, and H2S concentrations monitored at regular intervals until daily biogas production is less than 1% of cumulative biogas production. Biogas samples will then be characterized with a micro gas chromatograph and thermal conductivity detector for biogas quantity, CH4, H2S, total solids, and volatile solids. These data in turn will guide subsequent pilot-scale anaerobic digestion studies, in order to evaluate the economic potential for RAS salmonid farmers to convert solids waste into an additional revenue stream. Sub-objective 2.2 was conceived as follow-up research to a previous on-site USDA-ARS MBR study, and was initially planned to be carried out during the first half of 2020. However, assessment of the experimental-scale MBRs revealed that significant maintenance and potential retrofitting will be required to begin this study; therefore, we request that the research to support Sub-objective 2.2 be postponed for 48 months in order to carry out the necessary infrastructure rehabilitation to begin this study. Changes in milestones specific to USDA studies in the 6 RAS will be requested accordingly. In support of Sub-objective 2.3, The Conservation Fund's Freshwater Institute (TCFFI) scientists evaluated a number of technology platforms and potential commercial partners for advancing our precision aquaculture research. Foremost among these is Aquabyte, a Norwegian company with US-based programmers that has developed remote sensing, machine-learning technology to accurately assess sea lice load and Atlantic salmon biomass in net pens, in order to provide farmers with real-time production and fish health data to inform operational decision-making. The application of Aquabyte technology to land-based RAS salmon production will be novel and not without challenges, given the differences in rearing densities, water quality profiles, and other environmental factors between traditional net-pen rearing systems and state-of-the-art land-based RAS operations. At the time of report submission, dialogue between Aquabyte and TCFFI is ongoing, and details of potential collaboration are being discussed. TCFFI scientist have also approached two major Atlantic salmon producers, Mowi and Atlantic Sapphire, both of which are developing in-house precision aquaculture technologies. Mowi, through their recently announced partnership with Google/Tidal, is working on fish behavior and machine-learning for net pens. In comparison, Atlantic Sapphire has not publicly disclosed details of their internal precision aquaculture research and development efforts; however, this company is set to become a major U.S. stakeholder in Atlantic salmon farming, and therefore partnering with this company would have a direct benefit to U.S. industry and consumers. At the time of report submission, TCFFI scientists are focused on selecting the best group overall for collaboration, and this decision will be made in 2020.