DESCRIZIONE
Provided herein are systems and methods for producing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and/or derivatives and/or mixtures thereof by growing algae that produce the oils containing EPA and/or DHA and/or derivatives and/or mixtures thereof, harvesting the algae with fish in one or more enclosed systems, and then processing fish to separate and purify the EPA and/or DHA. The multi-trophic systems provided herein comprise at least one enclosure that contains the algae and the fishes, and means for controllably feeding the algae to the fishes. Also provided herein are the lipid compositions extracted from the fishes.