Food weight/calories after cooking

I was meal prepping for the week and I cooked these salmon fillets that came individually packaged in a bag. According to the nutrition facts, each fillet was 4oz with its respective calories. I didn't think much of it and went ahead and cooked them. Today I decided to weigh one cause I just got a food scale and I wanted to test it out and the fillet I weighed was between 2-3oz. My question is does food lose weight when you cook it? And if it does, does it still have the same calories/macros that is printed in the nutrition facts?