At Christmas time I must of fillet loads of salmon and discard the carcasses for the customer. My advice is always ask for the carcass back. The amount of meat left on there you will be surprise how may fishcakes you can make, pates you can create and stock cubes for future date.
It’s very simple to scrape the meat of the bone. All you need is a spoon and start scraping the meat off. As you can see below how much meat was left.
Ask for the carcass back and re-work it, and there is plenty of recipes on the internet so use a search engine like google. have fun.