This practice requires large amounts of manufactured fish food to feed the captive fish. Fish food is often made with small wild fish that have been ground into a fishmeal or pressed into oil. Normally, fish farms produce fewer fish than the farm consumes (to feed the fish). The industry has faced intense criticism for inefficient use of small wild fish that are an important food source for larger fish, marine mammals and birds in the wild, and are often the primary protein in diets of smaller and lower income coastal communities worldwide. Because of this, and because fishmeal and oil have become increasingly costly, the industry is exploring alternative feed ingredients.