you might need bill cody,greg are bob to tackle this one.i would think this fish was spawned late late last year.i'm in louisiana and my fish have not spawned yet so i would think this would be a large fish to be born this year.a 4 inch bass, i would think even in your managed pond would be 3-4 months which would make this fish born about november are december.i would not think this would be normal.just my 2 cents maybe someone else can give better answer.