It's not really fair to compare a fish to a cow moose... I've yet to see a deer, cow, or any animal continue to live a happy life after it was hunted. On the other hand, I have seen countless fish continue to live a happy life after they were caught and released.

Here is a great article explaining the "morality" of catch and release in a rebuttal to PETA.

http://www.saltstrong.com/articles/peta-catch-and-release-fishing/