The role of primary productivity of phytoplankton in the growth of common carp Cyprinus carpio L. in fertilized and unfertilized ponds

الملخص

Fertilization in fish ponds is essential for good growth and production of fish, as it achieves primary productivity of phytoplankton, which is considered the natural and good food for fish, thus less use of industrial feed. This study aimed to know the role of fertilization of fish ponds in primary productivity and then link it to their weight increase rate for each month. Five ponds were selected in the eastern Hammar Marsh, three of which were fertilized and the rest were not. Some environmental factors were measured (temperature, salinity, permeability, pH, oxygen, ammonia, nitrates and phosphate). Transparent and opaque bottles were used to measure primary productivity, and the weight increase rate for each month of fish was measured for each month. A clear positive relationship was found between primary productivity and weight gain in fertilized ponds compared to unfertilized ponds, which reflected the role of fertilization in increasing fish production.