G2O d.o.o. began developing the "tank by pond" (TBP) system about seven years ago, showing ongoing advancements. TBP is functionally similar to the widely recognized "Pond in Pond" or "In Pond Raceway System," with the basic principle that water circulates between traditional ponds (or any other water body such as a lake, sea, or river) and tanks for intensive farming.
Super-intensive farming is practiced in tanks, while semi-intensive or intensive farming is practiced in ponds. Water parameters are controlled in tanks with exchange of water, aeration, oxygenation, and monitoring, and ponds (besides fish production) function as filtration units for tanks.
So, from a functional point of view, TBP works as a Recirculation Aquaculture System (RAS) with seasonal production, at least for European fish farmers (it is open-air farming). Compared to RAS, TBP requires several times lower capital investment, lower running costs, and straightforward management.
With TBP implementation, production per hectare can be increased by at least 30 t/ha (it combines production in tanks and production in connected ponds) without any water exchange during the season (based on practical experience).
Naturally, such a load per hectare can only be achieved with high-quality feed.
Aller Aqua, as the exclusive feed supplier of G2O d.o.o., presents a critical factor for success. Besides the increase in production of carps, TBP enables simultaneous farming of other species that cannot be produced in ponds or cannot be produced in sufficient quantities (pike perch, sturgeons, catfish, etc.).
In 2022, in the TBP owned by company G2O d.o.o., a trial was performed as part of a diploma thesis from a Maribor Faculty of Agriculture and Life Sciences student. In that trial, carp farming and sturgeon farming were evaluated.
Two summer-old carp increased body mass by about 1000 % with a feed conversion ratio (FCR) of about 1.50 (Aller Master Float), and two summer-old sturgeon (Huso - huso) increased body mass by nearly 300 % with an FCR of about 1.0 (Aller Arctic SF).
The final density for carp was about 10 kg/m3 (or 20 kg/m2 water surface) and for sturgeons, about 5 kg/m3 of a 10 kg/m2 water surface. There were practically no losses, and energy consumption was about 4 kWh per kg of fish produced. Precise data about the trial will be published in diploma theses and scientific publications; that's why we operate with approximate numbers.
In 2023, company G2O d.o.o. in the same facility will perform a trial to reach 20 kg/m3 (40 kg/m2 water surface) of 2 summer-old carp with feed Aller Bona Float. Until now, trials have shown promising results.
Farmers in Europe and globally recognize TBP as a promising technology, so G2O d.o.o. has conducted several lectures and trainings and executed six projects related to TBP.