Growth and clearance rate of <i>Corbicula fluminea</i> in relation to fine sediment resuspension in eutrophic shallow lakes

Eutrophic shallow lakes have a high content of organic matter in the sediment that may be frequently resuspended. Whilst it is generally accepted that inorganic suspended matter has a negative effect on filtering-feeding bivalves in streams, it is unclear whether resuspended sediment in lakes with a high organic content will inhibit or support bivalve growth, the latter reflecting that resuspended sediment can increase food availability for Asian clams directly but also through release of nutrients, promoting the growth of phytoplankton. We conducted two experiments assessing the impact of different concentrations of total suspended solids (TSS) on the growth and feeding behaviour of Asian clams. We found that the growth rates in the low, medium and high treatments increased 12%, 36% and 53% respectively, when compared with the control with no sediment added. The effect on clearance rates of Asian clams differed amongst suspended fractions, and the clams showed significant preference for diatoms over other algae at high TSS. We conclude that an increase in TSS stimulated rather than reduced the growth of Asian clams, suggesting that eutrophication in shallow lakes provides more favourable conditions for the population expansion of Asian clams, an invasive species in many water bodies outside Asia.