Not only the quality drops, but the chances of food poisoning rise up to insult your bowels with potentially life threatening illness. Botulism being also a rare possibility.

Why chance giving your close friends a case of salmon squirts? Save those old vacumn wrapped fish for the in-laws, and free loading neighbors. Otherwise can your fish or huck the smoked fish in the freezer right away.

Pdf files
http://extension.oregonstate.edu/catalog/pdf/pnw/pnw450.pdf

http://www.uaf.edu/coop-ext/publications/freepubs/FNH-00325.pdf

Food poisoning is waaaayyyyy more common than the average person would know. Most of that coming from improperly cooked or processed home meals.

And I'm the one who has to smell your pants when your poop turns to liquid, and the only thing keeping it from running down your legs is your tightie whities. Nothing more sorry looking than a man with gut cramps who can't hold his pooh. Pay attention to how you store and process your fish and I won't have to see you at my work.

The percentage of salt in most smoked fish is not enough to preserve it against spoilage. Commercial fish processors use expensive equipement to measure the salt content, and it's not something that can be done at home.

Have fun

VHawk