Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Chiba 270-1194, Japan.
Water Sci Technol. 2012;65(3):426-33. doi: 10.2166/wst.2012.866.
The nuisance species Limnoperna fortunei is a freshwater mussel whose infestations have harmed water intake facilities, such as water supply systems. We investigated the changes in the drift and the settlement of L. fortunei along a headrace channel. The densities of the drift and the settlement both decreased dramatically with the downstream distance from the L. fortunei source (a reservoir). In comparison with larval densities in the reservoir, drift densities decreased by 10 to 25% at 0.5 km downstream from the reservoir, and were less than 2% at sites more than 4.8 km downstream. Although larval densities at midnight (0:00-2:00) were approximately 1.5 times higher than those at noon (12:00-14:00) in a shallow layer (3 m depth) of the reservoir, we found no diurnal variation of drift densities in the headrace channel. Settlement densities at the site nearest the intake gate were much higher than those of the other sites further downstream in the headrace channel. The L. fortunei adult population in the channel could reduce drift individuals by attracting the larva. The attraction probably induces the massive aggregation at the location of the channel immediately below the drift source, resulting in biofouling.
有害物种滤食性贝类福寿螺是一种淡水贻贝，其大量繁殖会损害取水设施，如供水系统。我们研究了滤食性贝类福寿螺在引水渠中的漂流和沉降变化。漂流和沉降的密度都随着距离滤食性贝类福寿螺源（水库）的下游距离的增加而显著降低。与水库中的幼虫密度相比，在距离水库下游 0.5 公里处，漂流密度降低了 10%至 25%，在距离水库下游 4.8 公里以上的地方，漂流密度低于 2%。尽管在水库的浅层（3 米深）中，午夜（0:00-2:00）的幼虫密度比中午（12:00-14:00）高约 1.5 倍，但我们没有发现引水渠中漂流密度的昼夜变化。靠近进水口的地点的沉降密度远高于引水渠下游其他地点的沉降密度。通道中的福寿螺成体种群可能会通过吸引幼虫来减少漂流个体。这种吸引力可能会导致在漂流源下方的通道位置发生大规模聚集，从而导致生物污垢。
