I've lost count of how many times I dry a single fishing hole and get 2 roes in a row from the 13 or so fish pulled. Then again I confess I don't much pay attention to the droprate and will possibly chop several batches of 50-60 fish and get nothing. RNG will RNG.
However when I do filet large batches of fish it usually comes to 1 roe per about 120 fish.