Fundamental Studies on the Ecology of Fishes near Artificial Reefs-I

To find out the environmental ecology and the gathering factor of fishes near artificial reefs, an automatic underwater camera with fisheye lens was developed. This could be set on the sea floor, and take 250 photographs lit by an electronic flash at every 30 or 60 minutes. At the artificial reefs off Sarushima Island near Yokosuka, where diving research was completed as mentioned in the previous paper, observation studies were continued using automatic underwater camera and self-recording current meter. As the results, some phenomena concerning Sebastes inermis, “Mebaru” in Japanese, superior near these artificial reefs were found to be as follows. (1) Sebastes inermis showed two-peak shaped behavioral characters in one day in its appearance on the photograph. (2) In 92% of the appearances, observation point corresponded to the artificial reef's upper side or near the tidal current. (3) In 85% of the above case, Sebastes inermis was seen to face the current.