Page 45 - fish_farms_curriculum

According to the species and life stages of the fish, feeds with different protein contents are

used. For example, while the crude protein ratio is 45-50% in carnivorous trout raising feeds,
this ratio drops to 0 in herbivorous carp feeds. Since tilapia cultivation is not done intensively

in our country, it is very difficult to obtain the feed, but carp feeds can be used in tilapia

nutrition. Crude protein requirement of tilapia fish is similar to carp and is around 0-35%.

Again, depending on the fish species and the life phase of the fish, the crude oil content in the

feed can vary between 10-20%.

5.4. Calculation of Fish Feeding in Geothermal System

Before installing the system in the geothermal system, it is important to know the type of fish
to be raised and the nutritional characteristics of this species. Because the life phase and water

temperature of that species are important criteria in calculating the daily amount of feed to be
provided to the fish. The amount of feeding will decrease as you move away from the

optimum growth temperature of the fish species.

While 5-7% of the total fish weight in the system is used daily at optimum water temperature

for juvenile fish, the daily feed rate will decrease as the fish grow, and it will decrease to 1-
2% in harvested fish.

For example, for feeding 5000 pieces of 50 g carp grown at 25°C with a daily feeding rate of
6%;

5,000 pieces x 50 g = 250,000 g = 250 kg total fish weight.

250 kg fish weight x 0.06 feeding rate = 15 kg daily feeding amount.

This amount of feeding can be given to the fish as 3-4 meals a day (4-5 kg) per meal, in the

form of morning-lunch-afternoon and evening meals.

It is necessary to renew this calculation monthly according to the average weight taken from

the fish and the daily measured water temperature. In order to get the average weight of the

fish, the water of the tanks is reduced and 20-30 fish are caught at random, the total weight is
measured with the scale and divided by the number of samples and the average weight of a

fish is calculated.

Another example is the feeding calculation with 2% daily feeding rate for 5000 pieces of 200
g tilapia fish at 28°C;

43