The arrival of the summer sun along the coastal waters of Alaska and British Columbia triggers an explosion of plant life greater in scale than the Amazon rainforest. The massive amount of plant life draws in huge amounts of wildlife to feast - including billions of herring and jellyfish, and sea lions and humpback whales that migrate all the way from Hawaii. Remarkably, the basis of all this life is something so small that it's hardly visible to the naked eye. The sun sparks the growth of phytoplankton - the microscopic floating plants that are the basis of all life here. In late summer the plankton bloom is at its height and vast shoals of herring gather to feed, attracting a number of other animals. Murres, small diving birds, round up the herring into balls. They dart up from below to pick off the fish, while gulls dive down from above. Pacific white-sided dolphins and sea lions also join the feast. After six months of little food, and thousands of miles travelling, the mightiest predator of all - humpback whales arrive. They not only take advantage of the balls of herring - a ready-made meal - but have also devised their own unique way of hunting in groups, by surrounding the herring with bubbles, in order to take the largest mouthful possible.