I've completed two factions (w/starters) and Craig - so I've skinned a fair number of fish. One thing I've noticed is that the roe appearance seems to be more bursty than might be expected from a purely even distribution. A number of times I've had three roe in less than 100 fish, and also gone more than 600 fish with none. But overall, it seems to be about 1/100 fish. It's also worth noting that ZOS could change that without notice at any time.I get perfect roe faster than I get blue colored fish.Then comes the fishing time - probably at least an hour on average to get each Perfect Roe.
I have 5 or 6 perfect roe in the bank.
Not counting the starter island rares, I have 2 blues caught.
Total time fishing is definitely less than 2 hours. I only started fishing two weeks ago.
Not sure if this matters, but I have Provisioning at 50 and food passives maxed.
I'm also pretty sure my roes came from fishing rivers. I don't recall any other water source producing them.