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หัวข้อ: Intensive rearing system for fish larvae research
เริ่มหัวข้อโดย: mei ที่ มกราคม 16, 2010, 08:24:17 AM
Intensive rearing system for fish larvae research I. Marine fish larval rearing system

Sagiv Kolkovski∗, John Curnow, Justin King
Research Division, Department of Fisheries, Western Australia,
PO Box 20, North Beach, WA 6920, Australia

Received 24 September 2003; accepted 24 May 2004
Aquacultural Engineering 31 (2004) 295–308

Larvae nutrition and in general larvae culture is considered to be the ‘bottle neck’ for marine
finfish culture. Fish larvae rearing experiments investigating nutritional factors or rearing protocols
are carried out in various systems, from small beakers to very large commercial tanks, making it
difficult to compare data across systems. A continuous supply of live or dry feeds and a controlled environment, i.e. temperature, filtration, photoperiod, oxygen and pH, are essential for any experimental or commercial system. These environmental factors are best controlled automatically in order to minimize variations between tanks. However, only a few automatic systems have been developed for marine finfish hatcheries. An experimental larval rearing system was developed to reduce variability amongst tanks (due to manual feeding and other parameters) and enhance control of environmental parameters while reducing the workload. The system includes 24 conical tanks with the option of either an up-welling
or bottom draining flow through water delivery system. The inlet water passes through a gas exchange
column that saturates thewater with dissolved oxygen and stabilizes the pH. The systemwas originally
designed for nutritional experiments using formulated feeds. The use of an up-welling water inlet
method extends the suspension time of inert particles in the water column and also helps to suspend
very small or passive swimming larvae. However, when the system is used to grow-on larvae or
juvenile fish it can easily be switched to bottom draining to provide self-cleaning water dynamics for
high organic loads. A unique outlet filter was developed that eases the daily routine of replacing screens when enriched live food is used. This filter can be exchanged with a screened standpipe and outlet surface skimmer when the bottom draining flow characteristics are engaged. The system is fully controlled by a single programmable logic controller (PLC). The PLC controls the light intensity, photoperiod, dimming time, live food and algae pumping intervals, substantially reducing labor requirements.

Crown Copyright © 2004 Published by Elsevier B.V. All rights reserved.

Keywords: Fish larvae; Rearing system; Diet; Experimental system