Serendipity the Pink Dragon (1983)

An adaptation of the children's book series "Serendipity" by Stephen Cosgrove. The boy Kona gets lost in the Southern Ocean and flows to Pure Island with a mysterious pig egg. The egg hatches and gives birth to the female sea dragon (sea serpent) Serendipity. The boy and the dragon are offered hospitality by the mermaid Princess Lola, who is the actual ruler of the island. They have to defend their new home from the pirate captain Captain Smudge who wants to plunder the island's treasure. The task is made easier because Smudge has found no crew for his ship and is acting alone.