Always fun to fiddle with a necro-thread. White fish sells anywhere from 50g to 100g each. So for a stack of 200 fish, that's 10,000g to 20,000g. Where on that scale depends on how fast you want to sell fish. Perfect Roe sells for anywhere between 8,000g and 10,000g. Average PR per fish is around 1:100 (give or take a few fish), but there's no guarantee that you will absolutely get 2 PR from a stack of 200. Sometimes you won't get any, while other times you might get 4!
So the sure bet for an absolute given value is to sell the raw fish. If however you want to make Psijic Ambrosia from the Perfect Roe, then better to filet the fish and take a chance on PR. You can sell PA for anything from 2750 - 3000 each, so that's 11K- 12K per 4-PA. With the Provisioner passive to get 4 per craft, that's a couple thousand more per stack of fish potential.
I've only just got into the fishing lark despite having been around since the beta and having accrued thousands of hours of gameplay. I have three copies of the game (one via Steam and two straight from Bethesda), two of which I let my family use. We've just started to fish. I actually purchased the Ambrosia recipe from another player for 13 000 Gold, not because I knew what it did, but because it sounded cool and I had a lot of Gold (saving up for one of the mansions costing around 1.2Mil). When I checked what it was for I was pleasantly surprised. I've used quite a lot of those Crown Store experience scrolls, but don't want to go buying any more as I think ultimately they are a waste of money, so being able to create a recipe that gives such a buff, even for 35 minutes sounded like a great idea; then I started to read all the comments about how hard it was to get the important ingredient, Perfect Roe, so went out and fished for hours, accumulating quite a lot of fish, but thinking was it worth it, I probably missed out on a lot more experience by not doing a dungeon. In fact, I could have done several group dungeons in the time it took to get those fish. Achievements aren't my thing, so I was only interested in getting lots of fish so as to hopefully get lots of Perfect Roe, which of course once I'd read all those comments saying how unlikely it was you'd get many out of say 200 fish. Well, imagine my surprise when I skinned my first fish and got a Perfect Roe. Yeah, tohugh it's been downhill ever since, lol.