Codfish. I was catching codfish in Boston Harbor. Something was wrong with this picture, but then again, it was perfectly right. After all, what could be more appropriate than catching the cod in Boston, the city that cod built? Appropriate, but hard to fathom. If you told the average Bostonian that he could catch keeper-sized cod - edible, non-mutant cod - in the shadow of the downtown skyline, he might think you had spent too much time in Boston Harbor. Having been born and raised in Boston, I felt the same sort of disbelief when Pete Santini, the proprietor of Fishin' Finatics tackle shop in Everett, called to invite me on an early-May cod trip with Captain Lou Abate. Cod in the harbor? I had to see this for myself.