Unfortunately, the Spark People database does not list every single food available. So, you'll have to find something similar. While there may not be a listing for Canadian White fish chowder, there is a listing for fish chowder from Legal Seafoods. they can't be all that different.
When dining out, you might want to check to see if the restaurant posts any calorie counts online. If not, once again, you do the best you can. This isn't an exact science.