Effects of Abalone Farming Cage Removal on the Benthic Foraminiferal Assemblages

To improve the aquaculture environment of an abalone farm near the Bogil Island, relocation was executed via the partial relocation of cages. The surface sediments were collected from nine stations to analyze the grain size, geochemical characteristics, and benthic foraminiferal assemblages in May (before) and August (after) 2015. Although no distinct environmental changes in the cage area were observed, the relocation area had an increased sand content caused by water circulation. In addition, despite the increase in the sediment temperature, the ignition loss decreased while the dissolved oxygen in the sediment increased. In the Q-mode cluster analysis, benthic foraminiferal assemblages were divided into Cluster I, which was affected by seawater circulation, and Cluster II, which was affected by the abalone cages. In the R-mode cluster analysis, Assemblage A before cage relocation was divided into Assemblages A1 and A2. Thus, the relocation area where the seawater circulation resumed experienced a change in its environment; furthermore, the benthic ecology showed the possibility of recovery.