浅海域の造成漁場と天然礁における底生生物相

摘要

In our previous study, we monitored the developing benthic communities on the artificial reef, which was deployed in March, 2008 as a larval settlement and juvenile nursery ground of abalone in Sagami Bay, from April, 2008 to October, 2009. These results showed that the artificial reef became available as a larval settlement and juvenile nursery ground of abalone around 10 months after its installation, and it attained the highest similarity between the benthic communities on the artificial reef and the natural reefs through the study period. We have also continued to investigate and analyze the benthic communities since October, 2009. The results were summarized as follows:(1)The seaweed beds consisting of Ecklonia cava have declined on the artificial reef and natural reefs the past few years, (2) The Gastropoda became the dominant species in the benthic communities on the artificial reef and natural reefs, (3) The dominat species of the gastropod fauna on the artificial reef shifted from carnivorous species to phytophagous species, (4) The commercially important mollusks resources have continued to decrease on the artificial reef and natural reefs, (5) The ability to increase and preserve the abalone on the artificial reef, has been lost. It is difficult to regain those functions of the artificial reef unless the rock surface is improved.