2020 Volume 15 Issue 2 Pages 121-131
Spatial, temporal and vertical variation of distribution in Asian mussels (Arcuatula senhousia) were described via belt transect observations by scuba diving, and the mussel bed coverage in a brackish river was observed over a 3-year period (2012–2014). The spatial changes in the mussel bed distribution showed a similar pattern over the 3-year period: the mussel bed spread from the deeper part of the river toward the shallow part of the river. Temporal changes in the mussel bed distribution followed two patterns: one was expansion from spring to summer and retreat during autumn, and the other was expansion from late autumn to the following summer and retreat during autumn. The relationship between the mussel bed coverage and environmental parameters (salinity, dissolved oxygen, water temperature, and water depth) was determined using Pearson’s correlation analysis. To identify the major habitat of the mussels, the median values of environmental parameters were compared with six levels of biomass categories of the mussel bed coverage, by the Steel–Dwass test. We presumed that major habitats are found in areas with a salinity of 9.2–17.3. This result was obtained from continuous field data (e.g., mussel distribution, water environments, and depth) indicating that caused by the patchy spatial and temporal distribution of the mussel.