Authors: E Vivekanandan
Publish Date: 1977/08/01
Volume: 55, Issue: 2, Pages: 99-112
Abstract
Reared in cylindrical aquaria containing different depths of water 25 to 70 cm the obligatory airbreathing fish Ophiocephalus striatus belonging to different weight classes 01 075 10 20 and 41 g was forced to swim vertically a longer or shorter distance per surfacing Surfacing frequency was a depthdependent activity in individuals weighing less than 20 g in all weight classes the frequency was nearly 2 times more in the series fed ad libitum on fish muscle than in the one where the fish were starved Owing to the sustained surfacing activity and the consequent fatigue the test individuals ‘hung’ to the surface for a definite period Neither frequency nor duration of hanging was depthdependent Mean hanging durations for the feeding series were 11 38 59 79 and 88 hr/day in the 01 075 10 20 and 41 g weight classes respectively the corresponding values for the starving series were 13 150 130 127 and 128 hr/day The distance swum by the feeding fish increased from 57 to 681 m/day and from 61 to 507 m/day in the 01 and 41 g individuals exposed to the minimum and maximum aquarium depths Feeding rate which was a depthdependent activity decreased from 280 to 113 g cal/g live fish/day with increasing weight Rate and efficiency of conversion also decreased with increasing body weight in larger fish conversion was dependent on volume rather than on depth of the aquarium O2 uptake of feeding fish was about 6 times higher than the starving ones of the tested weight classes at different aquarium depthsThis paper is part of a thesis submitted by the author from APA College PALNI to Madurai University in partial fulfillment of the requirement of the Ph D degree Contribution No 12 under a research scheme granted to Dr T J Pandian by the UGC New Delhi The author is grateful to Dr T J Pandian for valuable guidance financial support and encouragements
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