Carrying Capacity Of A Pond

[Jotham79]

A few years ago, I read something about green water ponds being able to support a biomass of .5 to1 kg per square meter of surface without supplimental feeding. The limiting factors were basically the amount of sunlight (energy) entering and the presence of sufficient nutrients. I'm figuring a "very rough" estimate that I could get .5 to .8 KG per sq.m. per year total. This means a lot of smaller fish or a few larger fish. Here is what I am wondering. Could I over stock a pond with fingerlings to a rate where the pond can carry them till they hit say 400 grams and remove half when they reach 300 grams and let the others grow on out.

I have a very good market for 300 to 400 gm fish at 45 baht and a pretty good market for fish over 500 grams at 50-55 baht. I want to maximize my return even if it means taking an extra month or so to grow them out.

Thanks,

Jotham

[ozzydom]

Jotham, the problem with your line of thinking is the possibility of under utilisation of your ponds.

If you were to keep your pond environment in a premium state to suit the wellbeing of the fishes you can certainly overstock. This would require good PH, keeping the phosphate levels up to promote phyto-plankton and micro organisms and probably 24 hour aeration.

The aeration aids both the fish and the micro-organisms.

Overstocking is like walking a tightrope, one minute everything is ok and the next you have a pond full of dead fish. A couple of dull windless days and oxygen depletion can wipe you out overnight.

When I work out how to post pics I will post a couple of examples ,its not a pretty sight.

After 6-7 years of trial and error,success and failure I now stock at 1.25 fry per sq m, at 700 grams this is about 1kg per sq m. without to many problems.This is about 128,000 baht per rai.

We retail at 80 baht kg farmgate which is 10baht per kg under local market price.

I dont know where you live or what competition you have but I would consider your sell price way to low to justify the work involved.

Dont forget that by overstocking in a no feed regime means your fish are going to grow slower from day1,so even if your remove half the competition at 300-400gram (maybe 4-5 months) the remaining fish are retarded by that length of time and may take up to 12 months to attain 600-700gram.

Costs are static whether you gross 50k or 100k per rai you still have the cost of pumping ,liming ,drying ,refilling and fertilizing plus restocking after each cycle.

Pla Nin in green water ponds is a one crop a year job so the object is to get most baht for the most fish at lowest cost.

[Jotham79]

I'm going to look into the prices I'm hearing, but we are mainly selling to people who sell in small country markets. We are very small at the moment until I get the new pond (about 2500 sq m) done and over haul our 3 existing ponds which will end up at about 1200-1500 sq m each. I'll look into the probiotic mentioned in the other topic.

Thanks