Interesting article on how long it takes a hook to rust.

http://www.worldwideanglermag.com/issue6/Conservation/hookrust.php

My understanding is that hooks in soft tissue are much more likely to be ejected by the fish's inflammatory response, than to rust out. I know that retained older style cadmium hooks were deadly for small striped bass, the absorbed cadmium caused renal failure.

A few years ago MA DMF did a study that looked at the release mortality of Striped Bass. I know this study is considered by fisheries managers as the best done on S-B. The study confirmed the previous understanding that in general, 8% of Striped Bass released after recreational catch will not survive. If my memory is correct there was a part of that study that looked at the subject of hooks but I do recall the results. One of you "search masters" might find the report on the MA DMF web site.

I always thought it was 2 to 3 months, I hate leaving hooks in but
if the release takes to long the fish keeps the hook