Chop onions, bell peppers, and celery and combine in a medium bowl.

Combine bay leaves, salt, peppers, thyme and oregano in a small bowl.

Heat oil in a heavy skillet over high heat until it begins to smoke.

Gradually add the flour, whisking constantly until the roux is a dark red-brown (2-4 minutes).

If the roux scorches, discard and start over.

Add half of the chopped vegetables to the roux and cook for one minute, stirring constantly.

Add the remaining vegetables and cook for two minutes, stirring frequently.

Add the seasoning mixture and stir to incorporate well. Cook for 2 minutes, stirring frequently.

Add the garlic and stir well. Cook for one minute more. Remove from heat.

Cook the andouille sausage in a large Dutch oven or stockpot over medium heat and set aside.

Place seafood stock into the large Dutch Oven and bring to a boil.

Add the roux mixture by the spoonful to the boiling stock, stirring until dissolved between each addition.

Bring the mixture to a boil.

Add the precooked andouille sausage and return to a boil, continuing to boil for 15 minutes, stirring occasionally.

Reduce heat and simmer for 10 minutes more.

Add the shrimp, undrained oysters, and crabmeat.

Return to a boil over high heat, stirring occasionally.

Remove from heat and let stand for a few minutes. Skim off any oil from the surface.

Serve hot over rice.