Thursday, 16 April 2009

National Center for Mariculture - Practical Training - Vol.2

After writing about my training work in my first few weeks i can write some more about things i learn during the first month, just before we are starting passover holiday here (8 days!).

During my first month i focused mostly about the groupers tanks and the nitrification process and as i tried to explaine, it is a very early research and many datas are being made by guesses and assumptions and mostly based on growth of a different type of fish, in this case the Gilt-head Bream.

During last two weeks i have started to be more involved with another research which also being made with cooperation with Aqaba, Jordan.
This research is much more advanced one and already used in Commercial methods in different companies in Israel. This current stage of the research is about making all the sludge and sediments which obtain Nitrate (NO3-) and Nitrite (NO2-) and Denitrificate them, meaning, Taking them out from the Solids to the air as gases and by that stop their flushing back to the sea and damaging the coral reefs.

The process might sound easy and simple and it is! but when you try to make it financial worth it is becoming tricky, for example, Picking a fish type which its market price is high, such as groupers or tuna and developing them to commercial production.

the financial problems of money flow between depertmants and offices in Israel made the grouper research to focus also about growth of fish without need for oxigen addition. Lack of funding lead to a situation which there is not enough money to even keep reserve and emergency oxigen tank. Air difusion is the solution which is being researched and should provide enough oxigen to the water, at least till the fish gets to marketing size (between 500-600 g) though this requires more tanks to be monitored.



Another problem we start facing with is the raising of temperatures here in Eilat, which today raise up to 35°c. This Helps for the Nitrification process though cause for lower oxigen levels and higher pH levels which follows to Higher CO2 levels too. CO2 levels, pH and Ammounium are the 3 main varients of the water condition and balance.

during the last month, the groupers grow from 118g to around 160g in avarage. The grouper is estimated to be the next main fish type used in aquaculture. For one thing it worth it - It is DELICIOUS!

Magen Yoav.
3rd Year Student - Environmental Engineering.

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