2023 Volume 79 Issue 18 Article ID: 23-18099
This study aimed to obtain basic information regarding methods for promoting increases in feed organisms by supplying sea floor substrate. Onsite experiments were conducted by using net sacks filled with gravel as simple specimens. The ultimate aim of the authors is to use the surface of the blocks and other structures in fishing ports to increase the sea floor space that is habitable by benthos on which fishes feed. The specimens were left on concrete foot protection blocks for one year or longer, up to two and a half years. The number and the wet weight of macrozoobenthos, particularly of annelids on which fishes feed, collected from inside the specimens were greater inside the port than outside the port. The number and the wet weight of macrozoobenthos collected were similar to those on the sea floor at the anchorage in the port. It is likely that the specimens began to provide a habitable environment for macrozoobenthos during the years these specimens were left on the blocks. Thus, it is suggested that the placement of gravel or other sea floor substrate on structures in sea areas promotes increases in organisms on which fishes feed and enhances the fishing port’s ability to serve as a feeding ground.
