I'm seeing them in guild traders after today's patch. At completely ridiculous prices 400-500k. So you can definitely get them now.

Got three of them myself. I've seen them for 30-50K a piece on release day. But I've seen a few being sold for 10K now. Don't think they will be that much worth at the end. You can only use them for the EXP boost drink. You can't do anything with them unless you have all 7 pages of EXP boost potion, so it'll take a while till the Perfect Roe become needed. But then what? People aren't gonna pay 50K for an ingredient they can farm themselves. Only people who need it are Provisioners, and they already know that they just need to fish to get it. Besides, where is the profit in selling the EXP boost drink when you have to pay crazy amount of gold for just the ingredients. No one is gonna buy one EXP boost drink for 100K. Prices will go down since no one is crazy enough to pay that insane amount of money for something they can farm themselves and in no way can earn back with selling the end product.

I have found quite a bit of it. For starters you can not get it from rare fish...no fishing in larger groups is not recommended if your are farming for it.

It seems to be a random drop from them. I have personally went through approx 200 fish, and had 0 p roe come out of it.. And just earlier today only 42 and got 2 from it.