Floating upweller systems for pond culture of freshwater mussels

Laboratory efforts to culture freshwater mussels are labor intensive and are hampered by the difficulty of providing suitable particulate food.  Caging in rivers provides access to natural foods but may be impractical.  Increasingly, ponds and pond water in indoor facilities are used as an alternative source of natural particulate food.  We are developing floating upweller systems (“flupsys”), used extensively for bivalve mariculture, for mussel culture in ponds.  Animals are held without substrate in screen-bottom containers that are suspended from a floating platform, and water is drawn through the containers by a pump.  We developed small systems suitable for experimental use, and a larger system (4.9 x 4.3 m) with 16 20-gallon bins for mussel grow-out.  We tested growth of 4 mussel species in 3 different water bodies over 5 months.  Juveniles were lab-cultured to 5 mm before placing in the flupsys.  Survivorship ranged among species from 30 to 100%, with most mortality in the first month.  Mean growth varied among species and among water bodies, and ranged from 5-10 fold increase in shell length and from 300-1000 fold in mass. These systems can be combined with lab production of juveniles for rapid grow-out.