What any fisherman worth his salt will tell you is that keeping freshly caught fish clean and iced, as well as quickly processing it, is critical to quality and, of course, safety from spoilage. Ideally, buy fish on the day you plan to eat it. If you must store fish for a day, or two at the most, wrap it carefully and put it in the coldest part of the refrigerator. If the fish is enclosed in butcher paper, place it in a lock-top plastic bag or rewrap it tightly in plastic wrap. (Salmon fillets and steaks will get water spotted if in direct contact with water or ice.) Fill a deep pan or bowl with ice or, better yet, use reusable gel ice packs, and place the wrapped fish on top. Store it on the bottom shelf or the back of a lower shelf in the refrigerator. (If using ice, drain off the melted water and add more ice as needed.)
You must take special precautions in order to freeze salmon successfully. How you wrap your fish and the temperature at which you store it are critical. For the last five years, I have had the opportunity to buy salmon directly from a fisherman. I purchase 75 lb [34 kg] each season and ask the processor to cut the salmon into whole sides or 1- to 2-lb [455- to 910-g] fillets and vacuum seal the packages. The salmon is flash frozen and airfreighted to me. I have a manual-defrosting freezer that maintains the fish just below 0°F [-18°C]. The fish keeps beautifully for almost nine months. (Manual-defrosting freezers are better than self-defrosting ones because the process of self-defrosting dries out frozen foods more quickly.)
Vacuum-sealed packaging is ideal. If you fish, have generous friends who fish, or are able to purchase high-quality salmon in season and want to freeze it, think about either purchasing a small vacuum sealer or making friends with a butcher or fishmonger and paying them to vacuum pack the fish for you. Otherwise, wrap the fish as tightly as possible (without air pockets) in several thicknesses of plastic wrap, place it in a freezer-strength lock-top plastic bag, squeeze out the air in the bag, and freeze the fish. If you have a chest freezer or upright freezer that will keep the fish below 0°F [-18°C], the salmon should be fine for up to nine months. If you are storing the salmon in the freezer compartment of a refrigerator, plan to use it within one month.
The best way to thaw salmon is to place the unopened package in a bowl or pan in the refrigerator. Fillets or a side of salmon usually thaw overnight, depending on the thickness. Thawing fish at room temperature can lead to bacteria growth because the outside of the fish gets warm and begins to spoil while the center is still frozen. If you need to thaw fish quickly, submerge the unopened package in a bowl of cold water until thawed. Depending on the amount of fish you are thawing, this could take one to two hours. Use thawed fish within twenty-four hours.