How big are krill and how many does it take to feed a whale?

The krill I have seen were reddish orange in colour, about 30 mm long, and en route to the Antarctic, the ocean around us was quite coloured. A bucket just lowered over the side produced a layer of krill about 20 mm deep at the bottom.

These shrimp like animals are a very important part of the food chain, living on phyto plankton and other tiny creatures, and in turn providing a food source for whales, seagulls, and penguins.

They are (wastefully) harvested as fertilizer.