Salt Water Aquaponic Research
Salt water aquaponics has had very limited amount of research conducted on it. The major difference to our fresh water system, in the model that we are trying, is that we are not trying to get nitrification to occur.
We started our experiments in mid-2008. Dan and Max, from the Department of Primary Industries in Queensland have been an invaluable help to us. We can not thank them, and the DPI, enough for their continued assistance and invaluable knowledge.
We have decided to commence by using a well researched fish. Lates calcarifer or more commonly known as Barramundi is an ideal fish because it is known to survive in recirculating salt water systems, it is well researched and there is good quality commercial food available for it. Here you can see Dan from the DPI introducing our first batch of Barra to the system.
And here they are after they have become acclimatized. A little too small to eat yet. We will see how they are in about 10 months time :-)
There are two sides to the salt water Aquaponics coin. We have decided to use Ulva to take the Nitrogen out of the system. Ulva grow best on Ammonia rather than Nitrate so we are trying to keep the balance without extensive nitrification of the Ammonia.
Firstly we put in some baskets to keep the Ulva in the grow trays.
Then Dan and Martin carefully looked at the Ulva and spread it through the baskets.
And so the experiment began. Our Ulva established itself quickly in our system and we managed to avoid massive sporalation. About 2 weeks after we started the basket nearest the inlet (pictured above) was nearly full (pictured below). This is approximately double the mass it was when it started.
We are hoping to develop our methods to a point where we can double the wet weight of the Ulva every week while maintaining a reasonsable stocking density of Barramundi. Much more work needs to be done.
A month later and all was going well with the saltwater system. The water clarity is excellent. The Barramundi continue to feed well and grow. The Ulva has not suffered from major sporulation and has now filled the first grow bed.
In fact we had to spread it into the second grow bed to give it room. We had planned to leave the second bed free for other marine algae and plants. We may harvest some Ulva in due course and put other species in but at this point the Ulva has a free hand. Here is the second (originally empty) grow bed after one month.
We continue to observe and increase our understanding of this interesting area of aquaponics.
Last Modified: Wednesday, 20-Aug-2008 11:16:35 EST
