That kind of depends on what you consider a "good" PI. A base 100% PI score requires an average of 20 points per object caught, including junk. Since Bass'ken fish are worth 6, 16, or 26 points for small, medium, and large respectively, it's near impossible to get 100% PI there. Small fish only would get you 30% PI, mediums only would get you 80% PI, and larges only would get you 130% PI. The problem of course is that mediums and large take forever.
From looking at the stats page, you seem to be attempting Overall right now, and as of this post, your Bass'ken PI (assuming no junk) is at roughly 45%. That sounds pretty small-heavy to me. Even if you got 2 larges, 4 mediums, and no junk every bucket you'd only have a 52.2% PI in Bass'ken though, so it's not as if you can make it go very high there. If you're competing for Overall, you're going to have to essentially cut your PI losses in Bass'ken and just make sure not to get any junk in Gambino, and little to none in Durem. Since Durem fish points are 22, 32, and 42 for small, medium, and large respectively, that's 110%, 160%, and 210% PI average for those fish. It pretty much balances out the low Bass'ken scores, and then some since you only need half of your catches to be from Bass'ken + Gambino.
Generally speaking, you should come out in the 90-95% PI range when going for Overall seriously once your buckets are all balanced out. If you're just looking for top-notch PI and not a trophy, well, just filter out the smalls in Bass'ken, since bucket time would be less of an issue then.