抄録
To elicit the effect of divers on the behavior of fishes, automatic underwater 16 mm movie camera was prepared. At four artificial reefs, artificial seaweeds farm, concrete block reefs, stone reef and pearl farm, a movie camera was set on the sea floor for two successing days, at almost same time and the same place. On each day, movie was shot for about 30 minutes. On one day, no diver swam during shooting, and on the other day, a few divers investigated fish species and their amount around the camera. From the movies, number of fishes and fish species were analyzed. As the results, some phenomena concerning behavior of fish were found to be as follows.
(1) In the case of diving observation, most of the fishes made only slight escaping behavior and some fishes swam away quickly, when diver approached them.
(2) When we compared the appearance rate of fishes on 16 mm movie at manned condition and at unmanned condition, the former was 0.4-0.6 of the latter.
(3) Number of fish species recognized from the movie was only 0.1-0.2 of the number by direct observation.
So it was deduced that the direct observation of fishes living near artificial reefs to be very useful, even if the fault of changes on fish behavior could be seen.
