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Journal of Experimental Biology, Vol 67, Issue 1 89-96, Copyright © 1977 by Company of Biologists
JOURNAL ARTICLES |
WN Tavolga
Thresholds for diffuse, broad-band illumination were obtained for the goldfish (Carassius auratus) by avoidance conditioning. The light source was a television cathode-ray tube whose output was controlled over a range of 140 dB by a combination of 'brightness' control, blanking of scan lines, and neutral density filters. The threshold was calculated in terms of irradiance to be 2-9 X 10(-6) muW cm-2 (+/- a standard deviation of 1-4). The determination of absolute, rather than relative, values, and the use of overhead, diffuse illumination provided data that would be ecologically and behaviourally relevant.