Using a large sharp knife, cut off one end of the watermelon so that watermelon stands at an angle. Using a razor blade or small knife, score an opening for the mouth. With knife, cut out and remove mouth. Cut out triangles for teeth; remove rind from teeth.
For shark fin, cut a triangle from removed rind; attach to shark with toothpicks. For eyes, attach two grapes with toothpicks.
Remove fruit from inside watermelon; cut into cubes. In a large bowl, combine watermelon, cantaloupe, blueberries and remaining grapes. Finely grate peel from oranges and squeeze juice. In a small bowl, mix preserves, orange juice and peel; add to fruit and toss gently.
Stand shark on a platter. Fill opening with some of the fruit mixture; add a few Swedish Fish if desired. Serve with remaining fruit.