This happened for real in Califonia a few years back. They saved a Seal let it go and bam Shark bait! 
I think his name was Chip the seal.
Kinda sad but a fact of nature, the ocean is a wilderness, one that man and many other creatures are not at the top of the food chain.
Found it, poor Chippy! This was an awesome story, one of those too wierd it has to be true ones. In a nutshell, he swam all the way inland up the SF River delta into Fresno, CA. CHP (California Highway Patrol/State Marshals) found him, and then ol' Chippy ("CHiPs") earned his name when he did what most beligerent/lost/confused creatures do when aproached by a state law enforcement agent, and took matters into his own hands:
After some rehabilitation, with nobody yet understanding why the stupid sea lion fled so far inland, he was released back to the bay from where his adventure started:
Only for us to realise very quickly just maybe he wasn't so stupid, but was rather maybe the first of his kind to think of a smarter idea:
SAUSALITO, California (AP) -- On February 9, a 321-pound male sea lion aka Chippy, was rescued by California Highway Patrol officers as it flopped along a road in central California near Los Banos.
According to center spokeswoman Cynthia Schramm, Surgery was performed at the Marine Mammal Center in Sausalito, to remove a bullet in the skull. The wound in the back of the animal's skull was no more than 3 days old when he was rescued.
Officials said, it is not known how the animal was wounded or how it managed to get so far inland. It may have been disoriented because of the wound and could have swum up the San Joaquin River from the ocean.
The sea lion was released at the Point Reyes National Seashore and soon after was snapped by a juvenile Great White shark. Beach Fire Chief Kenny Stevens said the attack was witnessed by 10 to 15 nearby surfers. The surfers reported seeing a 12- to 15-inch dorsal fin during the attack.
