Seas cover 70% of our planet, and are full of life. But we are not taking very good care of the sea. Sometimes we treat the sea like a great big dustbin. Rubbish, plastic, sewage and dangerous chemicals all end up in the sea, and this can harm the animals and plants that live there. Or we use big boats and big nets to catch fish - and catch more than we need, or hurt animals with our nets.

Now the animals have had enough. They've decided to fight back. First they're going to attack the fishermen with their big boats and nets.

Early the next morning the fishermen cast their nets into the sea. As the Swordfish cut through the main ropes with their long, sharp swords, the sardines swam into the nets in their thousands. Amazed by the size of their catch, the fishermen quickly pulled up their nets, but with a sudden SNAP! the ropes broke, rocking and rolling the boats over and over into the deep, dark sea.

"Hurray! We've done it!" cried the Swordfish to the sardines. "Let's go and see how the others are doing!"

Over by the shore, things were not quite going to plan at the sewage factory. Locating the main pipe that pumped its waste into the sea, the Blue Whales dived down. The youngest blue whale, excited by the mission, swam straight into the pipe.

"Didn't you listen to my instructions?" whistled the Pink Dolphin, now purple in the face. "Get out of there now, before the toxic waste kills you!"

But the young blue whale could not move a fin.

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