The Hollywood star, a passionate animal rights campaigner, previously wrote a letter to officials in support of Assembly Bill 376, which would make it illegal to possess, sell or trade sought-after fins.
Now DiCaprio is ramping up his efforts as authorities prepare to vote on the legislation – he has asked Californians to place calls to their state senators and ask them to protect sharks.
In a post on his Twitter.com page, he writes, “This is our last shot. Please help.”
The actor has also called for fans to sign a petition urging world leaders to do more for shark conservation.
Edward Norton, Kristen Bell, Paul Rudd and Scarlett Johansson and pop star Ke$ha are among the stars who are backing the bill to save sharks.