I am pretty sure that Gulp baits by Berkley are biodegradible.
Full disclosure: My company makes FoodSource lures, so obviously I'm not a disinterested observer to this discussion, but I wanted to make a few comments.
Regarding Gulp, it is made from a plastic called polyvinyl alcohol. Following up on Bruce Condello's post, Gulp might not be digestible. A recent study from the Maine Department of Inland Fisheries studied the effects of soft plastic fishing lures on trout. Gulp was one of the plastic brands tested. At the end of the tests Gulp lures were found to still be in the GI tract of the fish. A copy of the study can be downloaded at
http://www.fslures.com/press/coverage-extended.php?dg_entry_id=2856FoodSource lures, on the other hand, are made entirely of food ingredients. They were invented by Dr. Rusty Wright and other researchers at Auburn University. For a video of Dr. Wright, see
http://www.youtube.com/watch?v=id5-_h-LFns
