15 DECEMBER 1999
Sent: November 29, 1999
From: John D Skidmore <skidmore9@juno.com>
To: <shrimp@onelist.com>
QUESTION:
We are in the process of designing an indoor mating and maturation room for P. monodon. Does anyone have any information on the optimal size tank to get monodon to mate naturally? We have had great success in outdoor 30-foot and 20-foot diameter tanks and limited success in indoor 12-foot tanks. The problem with the outdoor tanks is that it limits our maturation of monodon to certain times of the year. Therefore, we believe that by placing a larger tank indoors we could get mating and maturation year around. Currently we have a space were we could place a 17-foot diameter tank indoors. Would a 17-foot tank be large enough to get monodon to mate naturally or do we need something larger? Any information would be appreciated.
John D. Skidmore, Jr.
General Manager, High Health Aquaculture, Inc.
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COMMENTS 1:
In reply to your question about the indoor tanks, we have ten cubic
metre, circular tanks of about the same diameter as what you have mentioned, and have found no problems with fertilisation of P. monodon
E-mail: digbyfleming@hotmail.com
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COMMENTS 2:
Our hatchery uses 12 foot diameter indoor tanks for maturation of P.
duorarum. We've noticed no problem in mating behaviors. Females with mature ovaries always yield fertilized eggs. We use a 2:1 ratio of
females to males.
Susan B. Butler
Crystal River Mariculture Center
Crystal River, FL, USA
E-mail: Susan.B.Butler@fpc.com
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COMMENTS 3:
P. monodon may indeed require slightly larger tanks for natural breeding than some of the other penaeids. We placed wild caught (290 g to 455 g animals) in 15 ft. dia., circular tanks indoors, in Java, ablated and furnished a 200-250 percent water exchange per day and the reproduction was excellent. The depth of the circular ferro-cement tanks was kept at about 36 inches or almost to the top of the tank since there was no problem with animals jumping out. Many folks have used much less water depth, but since the system was open-air, we got better temp. stability with the larger volume. We were especially careful to eliminate obstructions in the tank that might have interfered with the swimming and mating process.
Most spawns produced 700,000 eggs or more and the larger females (up to one pound in size) produced 1.2 to 1.4 million eggs. However, the natives used very large (24'X24'X 6' deep) cement tanks, which were covered with a bamboo hut to obtain natural mating, without ablation. I do not think that this method was as successful because there was inadequate water exchange to these tanks.
Your 17 ft. dia. tank should work well indoors.
Granvil Treece
E-mail: gtreece@unix.tamu.edu