**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** AQUACULTURE PRODUCTION, WITH FEED INPUTS OF FISHMEAL, FISH OIL, AND CROP MEALS, HAS BEEN IDENTIFIED AS THE MOST IMPORTANT CONTRIBUTOR ACROSS ALL ENVIRONMENTAL IMPACT CATEGORIES. ALSO, POORLY DIGESTED FEED INGREDIENTS INCREASE EUTROPHICATION EMISSIONS (NITROGEN AND PHOSPHORUS). WE WILL CONVERT THE MICROALGAE INDUSTRY'S LARGE VOLUMES OF UNDER-UTILIZED, MICROALGAL CO-PRODUCT-- LEFT-OVER BIOMASS AFTER EXTRACTION OF OILS, MARKETED AS A HUMAN SUPPLEMENT --INTO LOW-EMISSIONS, VALUE-ADDED, COST-VIABLE FEED INGREDIENTS. WE WILL: MANUFACTURE NEW CO-PRODUCT MEAL VIA DIFFERENT PROCESSING METHODS; EVALUATE THE NEW CO-PRODUCT MEALS VIA DIGESTIBILITY EXPERIMENT; IDENTIFY A SUITABLE LEVEL OF FISHMEAL REPLACEMENT BY CO-PRODUCT MEAL VIA GROWTH EXPERIMENT; DEVELOP A LOW-P DIET USING CO-PRODUCT MEAL AND CONDUCT GROWTH EXPERIMENT; QUANTIFY NUTRIENT FLOWS (N AND P) AND CONDUCT LCA MODELING; CONDUCT ECONOMIC MODELING AND QUANTIFY FINANCIAL VIABILITY OF INCORPORATING CO-PRODUCT MEAL IN RAINBOW TROUT DIETS; EXTEND COMMERCIAL APPLICABILITY OF PROJECT VIA A COMMUNITY OF PRACTICE THAT IMPLEMENTS ON-FARM FEED TRIALS. RESULTS WILL GENERATE THE FIRST ESTIMATES OF EUTROPHICATION AND GREENHOUSE GAS EMISSIONS AND FINANCIAL PERFORMANCE OF LOW-PHOSPHORUS AND LOW-NITROGEN LOADING MICROALGAL COPRODUCT DIET FOR TROUT AQUACULTURE.