NOVELTY - Algae are cultured by providing a source of water and a system comprising enclosures and water for culturing algae and culturing bivalves, culturing the bivalves that increase the level of dissolved nutrient(s) in the water in the system relative to the water from the source, culturing the algae in the water in the system, and feeding the algae to the bivalves at a rate so that the amount of algae produced in the system is greater than when the algae is cultured in the system without the bivalves.    USE - Method of culturing algae for producing biofuel or extracting lipids from planktivorous fishes (claimed).    ADVANTAGE - The method is low cost, and can grow algae in large production.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a method of producing biofuel comprising culturing algae, harvesting the algae by feeding the algae to the planktivorous fishes, extracting lipids from the planktivorous fishes, and polishing the lipids to form biofuel;    (2) a method for extracting lipids from planktivorous fishes comprising culturing algae, harvesting the algae by feeding the algae to the planktivorous fishes, and extracting lipids from the planktivorous fishes;    (3) a system for culturing algae comprising a source of water, a growth enclosure for culturing algae and a bivalves enclosure for culturing bivalves where the growth enclosure and the bivalves enclosure are in fluid communication, mechanism to regulate the rate and/or direction of fluid flow between the growth enclosure and the bivalves enclosure, mechanism for culturing the bivalves that increase the level of dissolved nutrient(s) in an effluent from the bivalves enclosure relative to the water from the source, mechanism for culturing the algae in the effluent from the bivalves enclosure, and mechanism for feeding a controlled amount of the algae to the bivalves so that the amount of algae produced in the system is greater than when the algae is cultured in the system without the bivalves; and    (4) a system for producing biofuel comprising a source of water, a growth enclosure for culturing algae and a bivalves enclosure for culturing bivalves where the growth enclosure and the bivalves enclosure are in fluid communication, mechanism to regulate the rate and/or direction of fluid flow between the growth enclosure and the bivalves enclosure, mechanism for culturing the bivalves that increase the level of dissolved nutrient(s) in an effluent from the bivalves enclosure relative to the water from the source, mechanism for culturing the algae in the effluent from the bivalves enclosure, mechanism for feeding a controlled amount of the algae to the bivalves so that the amount of algae produced in the system is greater than when the algae is cultured in the system without the bivalves, mechanism for harvesting algae by planktivorous fishes, and mechanism for gathering the planktivorous fishes from which lipids are extracted and converted to biofuel.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic view of water flow and trophic level associations in the bivalves-enhanced algae culture system.