TABLE OF CONTENTS Pages Symposium 1 - the National Sea ...

wastage between day and night feeding and has demonstrated differences in feed wastage
as small as 13 gram increments 1 .
Preliminary experiments in a partial recirculation double drain tank system have shown
that the units can differentiate between feed and feces for pellets as small as 2.5 mm.
Future Trials.
Additional feed control tests within 12 ft double drain tanks in a partial recirculation
system with Rainbow Trout fingerlings are currently being carried out. Answering the
following questions are important for this investigation: (1) How will the increased
effluent solids concentration created by the double drain design effect the performance of
the waste feed controller? (2) How effectively are fingerling pellets detected by the unit?
(3) What effect does the particle retention time in the 12 ft tank have on waste feed
detection and feed wastage?
Acknowledgements
The funding for this work was provided by the USDA-ARS under grant #59-1930-8-038.
References
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Ang, K. P. and Petrell, R. J. “Pellet wastage, and subsurface and surface feeding
behaviours associated with different feeding systems in sea cage farming of salmonids.”
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Anonymous. “The bonus of lower FCR’s.” Fish Farmer. 22 (1999): 36.
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Failures in Commercial Recirculating Aquaculture Conference. (1996): 552-561.
1 The experimental protocol and the methods were in compliance with the Animal Welfare Act (9CFR)
requirements and were approved by the Freshwater Institute Institutional Animal Care and Use
Committee.
3