Bluegill at mantua

[PACKFAN]

First trip on the ice today! We didn't have a ton of time but the 3 of us managed about 20 fish in a few hours. Just used the standard ice jig tipped with wax worms. 
I did find something new today that I've never seen. After I got finished filleting the fish, I was giving them a final rinse and noticed a small cream colored object in one of the fillets, it kinda looked like rice breast that ducks get. But with these, when I pulled them out they started to wiggle. After digging them out, they looked like tiny leaches.  Have any of you guys seen this before? 

Oh Oh I was sure hoping they wouldnt show up in the fish there. I started ice fishing Pelican lake way back in 1977 when I first got stationed here and we didnt see any fish with the grubs in them until the late 80s when a few started showing up and progressively got worse as time went on. They poisoned the lake off a few years back and we havent returned since then.