Claude Bradley Jr., age 14, of Dover, Del., for his question:

WHAT IS A KRILL?

A krill is a small, shrimplike crustacean that swarms in dense shoals, especially in Antarctic waters. Most of the 85 or more species range in length from about a half inch to almost three inches.

Krill use their feathery legs for straining out the tiny diatoms on which they live and generally emit a strong, blue green light that probably helps them congregate and spawn. Krill inhabit open seas and are an important link in the food chain. They are eaten by fish, birds and especially baleen whales, which consume as much as 4,400 pounds of krill in one feeding.

Shoals of the crustaceans have densities of about 35 pounds per cubic yard. Some species remain near the surface and others are found as deep as 6,500 feet.

Of great importance as a source of protein, krill are now fished for human use by Soviet, Japanese and Polish fleets.

The 13 member Antarctic Treaty nations have set up an Australian based bureau with power to limit krill catches. Scientists don't want to see fishermen upsetting the balance of nature.