USE OF DIATOMS IN P. VANNAMEI LARVICULTURE

From: Dario Zelaya mailto:aquaculture2000@yahoo.com
To: shrimp@yahoogroups.com
Date: 15 March 2002

QUESTION:

We were planning to run a nutrition study nursing L. vannamei post larvae in tanks with water seeded with live concentrated Chaetoceros sp. and feeding being supplemented with specific diets and this contrasted with post larvae nursed with pond water (wild algae). Our source of live concentrated Chaetoceoros let us know that from now on they have changed and are currently producing the diatoms Thalassiosira pseudonana.and T. weissflogii instead of Chaetoceros. Can anyone give some comments about replacing the Chaetoceros with the Thalassiosira p. or w. Any suggested reference to learn more about
Thalassiosira?

Dario Zelaya

e-mail: aquaculture2000@yahoo.com

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COMMENTS 1 :

I have used Chaetoceros and Thalassiosira in both monodon and vannammei larvae culture. In both I found the "Thal." to produce faster growing animals than with Chaetoceros.

Hank Bauman

e-mail: Bauman.BAL@starband.net

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COMMENTS 2 :

I have heard that T.w. is just as good, if not better than Chaet. T.p. is
smaller, whereas the T.w. is about 10-15 ľm.

John Scarpa

e-mail: Jscarpa@HBOI.edu

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COMMENTS 3 :

I have experienced with both, but I haven't seen any magic advantage between Thala and Chaet. I have learned trough the years that whatever you use to grow any organism is better for you but no to others. You should prove first with both and then decide yourself which one is better under your conditions. It is no algae all time, sometimes is water quality, quality of the nauplii, temperature, and supplement feed. It is more than one factor to help with your hatchery successes; also how you manage your hatchery is important in the finally result.

Robinson Bazurto

e-mail: buhocol@hotmail.com

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COMMENTS 4 :

We use a mix of Thala and Chaetoceros and the animals (vannamei larvae) do grow faster than with Chaetoceros only.

Oscar Hennig
Research Associate
Oceanic Institute
Kona Facility
P.O. Box 1423
Kailua-Kona
HI-96745, USA
Ph/fax: (808) 329 9293

e-mail: ohennig@lava.net

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COMMENTS 5 :

Be very careful growing Chaeto and Thal in the same room or facility.
Chaeto is the "weed" and your Thal will soon be 80% Chaeto.

Hank Bauman

e-mail: Bauman.BAL@starband.net

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COMMENTS 6 :

I am under the impression that Thalassiosira weissflogii is a slow grower compared to C. gracilis and so not suitable for commercial culture. Is this is a misconception? Also, is it not too big for zoea 1?

Laurence Evans

e-mail: Laurence@amatikula.co.za

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COMMENTS 7 :

I am not sure if one is slower grower than the other but it is likely that each different alga has his own optimum temperature of growth. In a hatchery it may be difficult or ineffective to raise different species of algae out of their optimum growth temperature.

If I remember well my past experiences, Chaetoceros would stand high lighting and high temperatures while a Thalassiosira tank may crash under these same conditions.

Eric Pinon

e-mail: epinon@ecua.net.ec

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COMMENTS 8 :

I started using Thalassiosira exclusively in 6 P. monodon hatcheries I operated in the Philippines in 1989. This was after 3 bioassays in which the Thal. fed pls were 25-30% larger by PL 2 than Chaetoceros fed larvae. We cultured it in 1 ton, outdoor tanks and the temperature would reach 33° in the hot season. We had no problems with it at all as long as we kept our indoor flasks clean.
I'm not sure what Thal. species it was though. I got it from Rick York, "the algae man" from Hawaii. It was about 10X the mass of Chaeto and we fed it at 10% of the cell numbers. We also used double the amount of silicate. It grows a bit slower too.

Hank Bauman

e-mail : Bauman.BAL@starband.net

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