Lampsilis cardium (Rafinesque 1820) is a relatively widespread species that inhabits numerous drainages of the Mississippi, Ohio, and Missouri rivers in central North America. Freshwater mussels play a key role in ecosystems, providing several valuable services, such as water filtering, nutrient cycling, habitat provisioning and mediation of food resources, as well as improving water quality and substrate stability. The use of microalgae for freshwater mussel aquaculture has increased due to the increasing need for alternative feed sources. As dietary nutrient deposition by freshwater mussels is not well understood it is imperative to understand what their dietary nutrient requirements are for conservation efforts as well as their role in ecology of the many rivers, and streams they inhabit.
A 90-day trial is underway to examine commercial aquaculture feeds that are readily available to grow freshwater mussels in a hatchery setting and determine if additives enhance their growth and survival. The trial is being conducted in a static aquaculture system that holds 36, 9L tanks with 20 juvenile mussels per tank. The tanks are filled with 50ml of sand, halfway with bio media, and have an air stone in them for aeration. One third of the system’s water flushes every 8hrs. The mussels are fed once daily one of nine treatments. Eight treatments are fed algae or algae with additives. These eight treatments are broken up between paste and freeze-dried algae, six of which have different additives including worm casings, probiotics, and live algae replacement in their formulations. The mussels are sampled for growth and length every two weeks, during this time feed rations are adjusted.
The current results (figure) indicate that treatments 4 and 8 outperformed all remaining treatments in terms of current mussel weight and weight gain (P<0.05). Updated results on production performance will be presented. Based on the current findings, one of the additives evaluated is driving the higher performance observed in treatments 4 and 8.