I don't think our book got this right--you cannot substitute grouper or cod for CSB. I believe this recipe is for sea bass. CSB is a different fish--more like sablefish or black cod. You cook it a long time and it is so oily it is hard to overcook--if you undercook it it's awful. It's not really a sea bass.
"He who sups with the devil should have a. long spoon".