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Determination of visual axis of tiger grouper juveniles Epinephelus fuscoguttatus, to develop a demand feeding system

Nai , Tan Han and Leong, Seng Lim and Rian, Freddie Firdaus and Chung, Fan Liau and Mukai, Yukinori (2011) Determination of visual axis of tiger grouper juveniles Epinephelus fuscoguttatus, to develop a demand feeding system. In: 8th Annual Seminar on Marine Science & Aquaculture: Sustainable Development & Management of Aquatic Resources, 8-10 March 2011, Kota Kinabalu, Sabah, Malaysia. (Unpublished)

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Abstract

In a demand feeding system, the fish turn on the switch of the feeder to get feed. In order to develop a demand feeding system with an infrared light sensor to which juvenile tiger grouper, Epinephelus fuscoguttatus visually respond, the visual acuity and visual axis of the juveniles were determined to obtain fundamental understanding of their vision. Three farmed juveniles were anaesthetized with MS222 and fixed in Bouin’s solution. The left retinae of each juvenile were cut into nine regions (Figure 1). The specimens were embedded in paraffin, cut into 6 μm thick tangential sections, and stained with haematoxylin-eosin. The density of cone cells (0.01mm2) in each region was counted in the stained sections. Visual acuity was calculated using cone cell densities and lens diameter. The highest cone density of each juvenile was 359 (bottom, B), 394 (temporal, T) and 380 cells/0.01mm2 (temporal, T) respectively. The estimated minimum separable angles of the highest density regions were 4.312×10-3, 3.661×10-3, 3.592×10-3 radian in each juvenile respectively. The estimated visual acuities were 0.068, 0.080 and 0.081 in those regions. These results showed that the visual axis of tiger grouper juveniles was in forward.

Item Type: Conference or Workshop Item (Poster)
Additional Information: 6616/7725
Subjects: S Agriculture > SH Aquaculture. Fisheries. Angling
Kulliyyahs/Centres/Divisions/Institutes: Kulliyyah of Science > Institute of Oceanography and Maritime Studies
Depositing User: Dr. Yukinori Mukai
Date Deposited: 20 Dec 2012 14:51
Last Modified: 20 Dec 2012 14:51
URI: http://irep.iium.edu.my/id/eprint/7725

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