1. First Israeli Modelling Week July 2-6, 2017 Nahariya, Israel The Carp problem
Wojtek Okrasinski
Faculty of Pure and Applied Mathematics
Wroclaw University of Science and Technology
Poland

2. Carp – Ciprinus Carpio

3. Milicz Ponds

4. Milicz Ponds and Barycz river

5. A bit of information
In the 12th century, monks began to excavate carp ponds - the Milicz Ponds were created. Waters were funnelled from the river Barycz. The more than 100 Milicz Ponds represent the world's largest collection of artificial ponds as the area spreads over 70 km². The Barycz plain has a surface of 5,535 km² - 10 times larger than Lake Constance.

6. A bit of history
The carp production is based on traditional farming practices. Most of the work, for eight hundreds of years, is hand-made by skilled fishermen.

7. Milicz Ponds – historical map

8. Some historical drawings

9. Some historical drawings

10. Photo

11. Present times

12. Autumn

13. Winter

14. Air view of Milicz Ponds

15. Air view of Milicz Ponds

16. Beginning of autumn

17. A lot of birds – about 200 species

18. Brief description of the carp cultivation
The production cycle of Milicz carp is 3 years and consists of 5 stages:

19. 1. Spawning
The best specimens are selected for spawning. It is carried out in natural ponds. Spawning takes place in May and June in shallow water. The hatching occurs after 3-5 days. After hatching the larvae measure is about 5 mm. 

20. Spawing

21. Larvaes

22. 2. Summer fry
The caught hatchery is reared in small shallow warm ponds, where hatching in 3-6 weeks, thanks to very good nutritional conditions, achieves rapid growth rate, in a short time. It grows to a weight of about 5-10 grams.

23. Summer fry

24. 3. Autumn fry
The next stage of the production cycle is the third one, in which summer fry is moved to bigger ponds. The fry is caught in autumn of the same year. Autumn fry has the weight 50 to 100 grams. The fry is fed with cereal grains until the end of September. 

25. Autumn fry

26. 4.”Kroczek” ponds
In the autumn the fry is moved to much larger areas ponds - from several to several dozen hectares of greater depths. Next autumn the carps of grams are caught . The second year carp is so-called „kroczek”(in Polish). It is the second year of production from spawning.

27. „Kroczek”

28. 5.Commercial ponds
Next the carp „kroczek” is moved to commercial ponds. In ponds carps are reared with other species of fish, not competing with them in of food. Fish in commercial ponds are fed with cereal. The most intensive feeding occurs from June to August. In October after 3 years of breeding begins the carp harvest.

29. Commercial carp

30. Carp cultivation - summary
Year of cultivation
Type of pond
Area of ponds
Average depth
1.Spawning m²
40 cm
First
2.Summer fry
(3- 5 weeks)
0.5-3 ha cm
3.Autumn fry
1-15 ha cm
Second
4.Kroczek
2-20 ha cm
Third
5.Commercial
5-50 ha (&more)
170 – 200 cm

31. View of different ponds

32. One of main farm problem
From the carp farm point of view the optimization of production from stage 2 to 5 is very important.

33. One of main questions:
How much fry should be used at the stage 2 to obtain the best results at the end of stage 5?
We can control the input at the point 3. We can also slightly control level of water at ponds and rate of feeding.

34. Carp as a very good feast meal

35. Thank you!
And good progress in the problem solving!