The present paper describes the detailed results of long-term monitoring on changes in population density and biomass of
Arcuatula senhousia in Lake Shinji and the Ohashi River. Routine quantitative samplings were almost monthly conducted for 8 years from November 2005 to October 2013 at selected stations in Lake Shinji and the Ohashi River.
A. senhousia inhabited the lower reaches in the Ohashi River over the years with high density and biomass, sometimes forming mat aggregations, while the numbers of individuals were lower level at Lake Shinji and the upper reaches of the Ohashi River. The higher abundance in the lower reaches in the Ohashi River was attributed to the source population in Lake Nakaumi, where
A. senhousia was the predominant benthic species. Population density and biomass of
A. senhousia were increased along the deeper riverbed, causing its distribution expanded from the middle reaches to the upper reaches. The distribution was likely to expand toward Lake Shinji when the salinity in Lake Shinji was over at least 6 PSU during May and July. The 8-years investigation of the present study revealed that population dynamics and shifts in distribution of
A. senhousia were tightly related with salinity regime in Lake Shinji.
抄録全体を表示