Studies On The Substrate Selection, Movement And Biodeposition Ability Of The Freshwater Mussels

The substrate selection, movement and biodeposition of the freshwater mussels were studied. The adaptability of freshwater mussels in different environmental cond-itions was explored, The results can provide a scientific basis for the protection of freshwater mussels, ecosystem restoration of lake and river and management. The main results are as follows:1. Substrate selection experiment, Cuneopsis pisciculus and Cuneopsis heudei prefered mud substrate, the percents of the time staying in mud substrate were34.8%±3.0and34.4%±4.0; Unio douglasiae prefered mud-sand and gravel substrate, the percentage were40.3%±3.7and29.3%±3.6; Lanceolaria grayana prefered sand substrate, the percentage was40.5%±4.3. Except Anodonta woodianna pacifica, the remaining mussels had significant differences in the four substrates (P>0.05). Anodo-nta woodianna pacifica had no significant differences in the four substrates, showed its strong adaptability, can survive in the four kinds of substrates.2. Movement experiment showed, Anodonta woodianna pacifica moved the fastest in the mud, with an average velocity per individual of2.27cm/h, Acuticosta chinensis moved the slowest,0.2cm/h. In the gravel, Anodonta aracaeformis moved the fastest,0.93cm/h. Schistodesmus lampreyanus and Lamprotula fibrosa is the slo-west, their average speed was0.03cm/h. The mussels moved slowly in the gravel substrate,2.45times less than in the mud substrate, some even fixed.3. Mussels biodeposition ability was different. Three suspension conditions, the mussels have significantly reduced the ability of the water turbidity. Cuneopsis piscic-ulus and Lamprotula caveata are the best in the set groups, have the strongest power of remove the water column particulate matter. Cuneopsis heudei was the weakest.4. Different mussels have distinct ability of deposition in the different suspension concentrations.When lg/L, because of its turbidity was lower, changes in the general trend is relatively flat, so to the end of the experiment, water was almost clear.2g/L, mussels increased slowly at first and then decreased with the contribution of the water body.4g/L Cuneopsis pisciculus, Cuneopsis heudei and Schistodesmus lampreyan- us’s turbidity trends showing first increased and then decreased and last increased trend. Acuticosta chinensis, Unio douglasiae, Arconaia lanceolata, Cuneopsis heudei and Lanceolaria grayana showing the trend that first increased and then decreased slowly.