That's been tried here as well but with lobster bait. The herring is put into a barrel, covered and set out in the sun. After a while the fish oils rise to the top but the smell is a whole lot higher;lol.
The main problem is that this mixture will get a lot smellier by the end of the summer if you put it into a large bag of baits. Now you might think that it is a good thing; but when you open the bag you will have a choice; loose your lunch or hold your breath, lol.
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