Save for those small animals that graze on diatoms, every free-swimming creature lives on the flesh of others smaller than itself. And it in turn is food for others larger.
Copepods, for example, are among the most important food animals. These tiny animals, ranging from pinhead size to a quarter of an inch, eat the microscopic diatoms. Baby herrings eat copepods by the thousands. But squids, like many other sea creatures (and man too), enjoy herring.
Catching a fish in its tentacles, the squid with its horny, parrot-like beak bites out big chunks, and down goes herring into squid. Then along comes a bass and eats the squid. Finally the adult sea bass—weighing perhaps 6 pounds, and about 18 inches long—unless it becomes prey itself, will eventually die and sink to the bottom, there to be eaten or to decompose into fertilizer for the diatoms. So the cycle starts again.
About 10 pounds of food is required to build one pound of the animal that eats it. Thus it would take 10,000 pounds of diatoms to make 1,000 pounds of copepods to make 100 pounds of herring to make 10 pounds of squid to make one pound of bass to make 1/10 pound of man.
