Artificial seaweeds farm plant, experimental floating reef made of steel, had been anchored at the depth of fourty-three meters off Tajima in the Japan Sea. Mean component of the plant was a shelf (22×22m square) settled at ten meter depth layer and an observation tower rose at the center of the shelf toward the surface. Two years after the plant had been anchored, the activity of fishes around the plant was investigated by direct observation and by some automatic recording instruments. As results, some phenomena concerning the behavior of fishes were found as follows.
(1) Around the plant, seventeen kinds of fishes were found and the dominants were
Seriola aureovittata,
Oplegnathus fasciatus,
Sebastes inermis and
Navodon modestus. (2) Distribution and activity of the fishes around the plant varied in the daytime and in the nighttime.
(3) Fishes were classified into all day dependant type and daytime dependant type to the plant, but this classification seemed to vary according to the life-stage of each kind of fishes.
(4) Most of the fishes, including young
Navodon modestus, belonged to all day dependant type, and they distributed within twenty meters of the plant horizontally and vertically, all day.
(5)
Seriola aureovittata and adult
Navodon modestus belonged to daytime dependant type, and they distributed thirty meters or more from the plant, in the daytime. In the nighttime, they were not observed swimming around the plant, and
Navodon modestus was considered to rest on the bottom under the plant.
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