Trouts farm

[Valentin Grozdev]

Greetings! Nice forum you have! Found a lot of information here! but cant find  nothing about trouts!

 I want to make farm (closed type) for trouts, but don`t know nothing about trouts and farms (first project). Can trouts be raised in tanks (3,4 or 7000 gallons size)? or i do have to make channels with flow trying to imitate their natural surroundings? I know they are slow growing, but just how slow?

Good questions is why not more simple fish for first project? I`m last year student in business finance and know there is plenty of market for this fish here. Anyway i want to do it the right way, so we can achieve fast reproduction at good price, thanks!

[Valentin Grozdev]

Glad that my assumptions are wrong! Was a bit disappointed of 1.1cm grow per month, but i read it from some obviously wrong source.

Are you using some equation for 3lbs/gallon (5lbs with better flow) ? Correct me if my math is wrong in 7760 L tank would fit 6291 trouts if i harvest them when they weight 0,5kg(1 pound)? this is calculated using your results 3lbs/gallon.

matthew ferrell said:

Bad assumption. 

Trout grow an inch a month, 2.54 cm/month.  Also your weight is WAY off.  A 13-14 inch fish is about 1 pound if body condition is good.  Also lets not assume your water will have 100% saturation, because why would you care then about water flow.  Unless of course you are talking incoming water, which is still hard to do without pure oxygen, and even then it will over shot 100. 

Lastly let's assume you want your fish to grow at optimum levels, that means the lowest your DO can go is 60% sat no matter the temp. 

After that its super easy.  I can safely grow about .3lbs/gallon with 2.5 exchanges an hour with FRESH flow through water in tanks with airstones.  In my raceways, which have 4 levels I can do better.  At 4 exchanges an hour I can grow about .5lbs/gallon.  My incoming water is spring fed, and never goes above 94% saturation even with 3hp of blowers.  Now when I turn the oxygen on then that's another story, I could do way better, but the density and disease becomes the limiting factor.  Lastly I could grow more fish per gallon if I didn't have so many raceways, but since each raceway pours into the one below them I managed for lowest oxygen in the system, which is at the bottom of raceway 4.  Now I add pure oxygen at level 3 so that carry capacity is equal in the first two and the last two, and so I do not waste oxygen on tanks that do not need it.

Simple right?

[Vlad Jovanovic]

Valentin, Mathew said 0.3lbs/gallon and 0.5lbs per gallon...

So that's 136grams per 3.78 litres of water with the less flow and 227grams per 3.78 litres with the better turnover/flow...

So, there's no way you can get 6291 half pound (227 grams) fish in 7760 litres of tank water (...by the way in a previous post you stated that 7760 litres was 1705 gallons, this would be true if Mathew lived in Britain. But that's not the case. British Gallons and US Gallons are not the same thing, so 7760 litres is 2050 US Gallons...Not 1705...

[matthew ferrell]

Wow for whatever reason I converted with 2.78.  Thanks for the correction. 

Back to the topic at hand.  We 'thin" our fish when the 2000 gallon tank hits 1,000 pounds.  We do this because it becomes too expensive to add oxygen to the system to maintain 60%+.  However with the right elevation we could do better without additional cost.  We have 6" drop between tanks, because our elevation is almost nothing.  2 feet is a good minimum but since we do not have that option we use the blowers.

We stock at what will get us to grow to 500lbs in 6 weeks.  So it changes based on fish size.  Obviously we can stock higher numbers of fish if they are small, yet it is important to remember that smaller fish in aggregate consume more oxygen per unit weight than large fish.  That is to say 1 5lb fish consumes way less oxygen that 5 1lb fish.  That is because feed rates and growth rates are different.  Also in recirculating systems water quality will also be different lb for lb, again due to %bdy/wt fed.  All this is being said to answer the question this way.  It depends.  I would spend little time worrying about recreating natural conditions and spend time figuring to how to get the best water you can. 

[Valentin Grozdev]

Oh, shit what mess i did! I know something was wrong! How can 6000 fish (weighting 0,5kg each) fit in 7760 liters  :D

I really own you at least tour in Bulgaria or to introduce to bulgarian women (one of the best looking) :P

About the water quality, before we buy the land, a drilling company will come and take examples from the water, will calculate  water flow (want 2500L/m at least), temp, bacteria, full chemical analysis, etc, want everything to be 100% sure.

again big thanks for helping me with the calculation, in my country those farm types almost don`t exsist and cant find specialist to explain me all those key important things!

[Kaspars]

I do trouts for few years. From 1 gr fingerlings to 2kg big ones. I have made flow through system where water come by gravity from upper pond and goes through round beton fish bassins back to big poung. I realize that ANY investment, doesn't matter big or small will rise costprice of fish. So, i made it very cheap. Only expences is feed and fingerlings ( costs alsmost nothing ). I have very good water conditions in my ponds. DO never less than 10-11 ppm and saturation more than 100%. Of course, in fish bassins there is less because of stocking and feeding. I case of low level i use air pump. Till now all works perfect. When trouts are ~300 gr i put them in net cages in pond. They grow fast. For example, now i have them about 100 gr and in september they will be ~500-800 gr. Then quite in winter time. Feed ratio ~1.3 but i do feeding by hands, the most effective way. I did also project to get some EU funds for recirculating system but decided to stay independent from all these birocratic guys.... 

[matthew ferrell]

How are you getting supersaturation?

[Kaspars]

I don't know...... At least all measurements show it up. But only in big pond, not in bassins where small trouts are growing up. Overe there saturation is not more than 85%. DO is not less than 7, at least i try to follow this level. My advantage i all this is that i have specialized fisherie with educated people right next to my village so i can ask a question every time....

 

[Valentin Grozdev]

I want to growth them to 250 or 500 grams, so based on upper calculation 0,016L/1gram ( with good flaw) will need 4/8 L water per fish with those sizes. So if i  use 33,500L tanks would fit 8375 (250 gram) fishes for 6-7month cycle and 4187 (1pound) fishes for 12-13 month cycle, right?

cant find specialist, my bachelor is international economics relations and math is not my strong side :) but need to learn how to calculate water flow needed for 250/500gram fishes or just exchange needed for 1 gram of fish. Big thanks again! :D

Vlad Jovanovic said:

Valentin, Mathew said 0.3lbs/gallon and 0.5lbs per gallon...

So that's 136grams per 3.78 litres of water with the less flow and 227grams per 3.78 litres with the better turnover/flow...

So, there's no way you can get 6291 half pound (227 grams) fish in 7760 litres of tank water (...by the way in a previous post you stated that 7760 litres was 1705 gallons, this would be true if Mathew lived in Britain. But that's not the case. British Gallons and US Gallons are not the same thing, so 7760 litres is 2050 US Gallons...Not 1705...

[Kaspars]

Dear Valentin.

All this is just book readings. Reality is different. The general rules are following: in raceways you can grow up to 30kg/m3 of water. In recirculating systems you can do at least 60-70kg/m3 of water. But all depends.... Water quality, feeding rates, feed quality, etc. I am talking about trouts. For example, channel catfish you can do 200kg/m3 easy!!!!:)

Start slow, experiment and enjoy results!!!

I am not very good in aquaculture, neither math. "Choir conductor and musical teacher" is written in my diploma....:)

[Vlad Jovanovic]

No problem. Your math was good, you just didn't see a couple of decimal points and were converting to British Gallons instead of American ones...

All I know about trout is how to catch, cook and eat them...

[matthew ferrell]

You are getting super sat from the plants int he pond.  Do me and yourself a favor.  Measure the oxygen right before sunrise.

Kaspars said:

I don't know...... At least all measurements show it up. But only in big pond, not in bassins where small trouts are growing up. Overe there saturation is not more than 85%. DO is not less than 7, at least i try to follow this level. My advantage i all this is that i have specialized fisherie with educated people right next to my village so i can ask a question every time....

 

[Kaspars]

I know this trick....:) No big difference, Because.... There is no plants in my pond. They was before but 28 grass carps (Ctenopharyngodon idella )  eat them all out.  Anyway, i am happy and in general, my trouts are growing fast enough. As i told before, this is just my hobby and i am happy with the results and thanks to "i don't know realy who", my water parameters are excellent. I do also  inconnu ( Stenodus leucichthys nelma ) , whitefish in cages and all the rest of cyprinids in pond. Even in strongest winters with ice of 50cm there is no dead fish at all. DO is still more than 10-11 and saturation more than 100%.