The best way to handle this is to find the bones and cut them out.
Just follow the bones with a sharp knife and cut along both sides to remove.
Discard the bones.
The portion on the left is the belly portion and on the right is the loin.
Cut the loin in half and you should have three six ounce portions.
You can also print this recipe, show it to the fish monger and have him do it for you.
Salt and pepper both sides of the fish.
Place a heavy pan over high heat on the stove.
Add just over a tablespoon of oil to the pan.
When oil is hot, but not smoking hot, lay the fish into the pan.
Let fish cook on one side for a couple of minutes.
The fish should just begin to turn golden brown.
Turn fish over and place pan into the oven.
Roast fish in the oven for about 5 minutes.
Remove pan from oven and crack open one piece of fish to make sure it is cook through.
Place fish onto a plate.
Squeeze lemon over fish; drizzle with remaining oil and sprinkle with parsley.
New Taste Thinking:
If you can't find (or afford!) MSC Chilean Sea Bass you can substitute halibut or salmon for this recipe.
When this fish first appeared about 25 years ago people were amazed with it's buttery flavor and texture. The popularity of Chilean Sea Bass exploded for the next decade or two. Unfortunately this fish has all sorts of issues as far as over fishing and fishing practices. I personally have not had this sea bass for many years. I recently noticed that the Marine Stewardship Council has been certifying a small amount as sustainable. http://www.msc.org/ .
It is difficult to describe the wonderful flavor found in this variety of fish. The price is high and it is not an everyday item but well worth the splurge.