Finally, near the equator ( 0-30° North and South) the NPP is relatively the same. Why is that?

Once on the ground, the air returns to the equator. This convection cell is called the Hadley Cell and is found between 0 degrees and 30 degrees N. There are two more convection cells in the Northern Hemisphere.The air that rises at the equator does not flow directly to the poles. Due to the rotation of the earth, there is a build up of air at about 30° north latitude.

Explanation:

answer: 20 percent

the fish culture has become a developing commercial practice in developing countries which is already prominent in developed countries of the world. the major fish protein demand is being supplemented in developing countries is   fishing to meet the needs of the growing population. therefore, in some developing nations, the percentage of animal protein from fish in the diet can be as high as 20 percent.