University of Wisconsin Can fish as soon as possible after you catch them. Immediately after catching, gut the fish and chill to delay spoilage. Do not leave fish exposed to sunlight, or throw them in the bottom of the boat where they will get stepped on and bruised. After cleaning, pack fish in a cooler of crushed ice. You want to get the fish home in the best possible condition.
Bacteria can cause spoilage under ordinary conditions.
These organisms are everywhere in the air, soil and water. They are naturally associated with fish that are alive and in the water, or after their removal from the water and before you pack them in a jar. Before canning, sort the fish according to variety, size and condition. Remove head, tail, fins, and scales. Wash and remove all blood.