Shrimp biomass calculator
Shrimp biomass is the number of live shrimp in the pond multiplied by their average weight. Enter the postlarvae stocked, your survival estimate and the average weight from the last sampling to get the biomass, the load per hectare and, with the rate from your feed table, the daily ration.
- Postlarvae, survival and weight in
- Biomass and kg per hectare out
- Daily feed from your own table
- Runs in the browser, no sign-up
Calculate pond biomass
The count placed in the pond at stocking.
Your current estimate for this pond. It is the least certain input, see below.
From the most recent sampling of this pond.
Adds kg per hectare and stocking density.
Read from your feed table for this weight. Adds the daily ration.
- Estimated shrimp alive
- - shrimp
- Pond biomass
- - kg
- Biomass per hectare
- - kg/ha
- Stocking density
- - PL/m²
- Daily feed
- - kg/day
Calculations run in your browser. Nothing is sent or stored.
How is shrimp biomass calculated?
Biomass is the live count multiplied by the average weight. The live count is the postlarvae stocked multiplied by survival. A pond stocked with 500,000 postlarvae, at 80 percent survival and an average weight of 12 g, holds 400,000 shrimp and 4,800 kg of biomass.
Every decision that follows the sampling uses this figure: the ration, the harvest forecast, the partial harvest that relieves a crowded pond. That is why the two inputs behind it deserve more scrutiny than the multiplication does.
Survival is the input that is usually wrong
A cast-net sample gives a reliable average weight. It does not give a count. Survival in an open pond is an estimate until the pond is harvested, built from feeding tray response, catch per throw and whatever mortality was actually seen, and the estimate tends to hold its starting value long after the pond has moved away from it.
The error passes straight through. A survival estimate ten points too high makes the biomass ten points too high, and the ration built on it overfeeds by the same margin every day until someone corrects it. Keeping the estimate current, pond by pond, is worth more than any refinement to the formula.
From biomass to the daily ration
Daily feed is the biomass multiplied by the feed rate for the current weight, taken from the feed manufacturer table or the farm's own. The rate falls as the shrimp grow, so the same table gives a different percentage every sampling, and the ration has to be rebuilt each time the weight moves.
This page takes the rate as an input on purpose. Feed tables differ by feed, by system and by farm, and a generic number would be a guess dressed as a recommendation.
One pond at a time, every sampling
A farm-wide biomass averaged across ponds hides the pond whose survival collapsed and the pond that is ahead of plan. Computed per pond after every sampling, the same arithmetic shows which ponds are due for a partial harvest, which are eating more than they are growing, and what the farm will actually have to sell.
AquaOS keeps this number per pond automatically: every sampling, mortality and harvest updates the live count and biomass, and the next day's feeding plan is built on the new figures.
Frequently asked questions
How do you estimate shrimp survival in a pond?
Farms combine several indirect signals: how much of the ration is eaten from the feeding trays, the catch per throw during cast-net sampling, and the mortality observed at the pond edge. None of them is a count, so the estimate should be revised whenever the signals move and reconciled against the harvest count at the end of the cycle.
How often should shrimp be sampled for weight?
Often enough that the feeding plan never runs on a weight that has gone stale. Many farms sample on a fixed weekly routine. Whatever the interval, the biomass and the ration should be recalculated on the day the new average weight comes in, not at the end of the week.
What is the difference between biomass and harvest yield?
Biomass is what is in the pond today, estimated from survival and sampled weight. Harvest yield is what was actually weighed out. The gap between the last biomass estimate and the harvest weight is the best measure of how good the survival estimate was during the cycle.
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