In Canada, we have the Canadian Copyright Act, a federal law that was created in 1867. According to the Act, a work is protected for the life of the artist and then for a period of 50 years. However, it is obviously impossible to copyright ideas, information, and facts. Copyright only covers the expression of ideas, and the arrangement of facts. The issue with mashups is that they highlight previous artists specific expression of ideas and therefore violate the Copyright Act.
But there is hope....
"It is a tricky balancing act, creating derivative works like the maship up without falling afoul of copyright legislation. Both scholars and legal experts support the notion that derivative works can be creative works in their own right, works that move well beyond their source" (Schneider 3).