Wednesday, 27 May 2009

Mid Term Summary - Practical Training Vol. 3

After 3 months i could make a short summary on my experiences here. Today i participated in a meeting together with all grouper growers in Israel.

during 2008 and 2009 young groupers which developed in NCM has been part of some experiments in few different conditions of water qualities around Israel by private companies and by national institutes as NCM. My experiment was to check the ability to reduce the amount of sea water intake and the ability to recirculated the water in the system and by that have control about different nutrients (mostly different Nitrate compounds) which flow back to the sea.

The other experiments held by other companies tested the ability to grow the grouper in low salinity (5ppt compared to 40 ppt of sea water) some in recirculated systems and others in flow through systems.

During May the experiment had to stop due to a terrible unknown illness which caused more than 50% mortality in 3 weeks and continued to this day. The main catalyst was a pathogene called Mycobacterium, a type of fish Tuberculosis and dangerous also to humans. The mycobacterium doesnt have any known treatment and the only way to fight it is by providing the fish the best water quality conditions.

The illness is still officialy announced unknown since it has been detected through all different groupers and other fish departments. Another reason was that the mycobaterium causing a chronic harm and it is not accute as it is weaken the fish immune system and exposing it to other pathgenes.

The grouper growth is on the starting stages of studying and during next few years a lot more will be known about the white grouper behavior, limits and social paterns which will provide the ground for an environmental type of aquaculture which is also extreme financial worth and therefore worth to be held by all companies.

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