Make the stock by bringing about a gallon of water (including oyster water, if available) to a light boil. Add all the remaining stock ingredients. Return to a bare simmer and cook for about 30 minutes. Strain the stock and discard all the solids.
In a large pot, heat the vegetable oil until it shimmers. Add the okra and cook, stirring, for about three minutes. Remove the okra and drain the pot, but leave a film of oil in it.
Add the onions, bell pepper, and celery. Cook until the vegetables are soft. Then add the stock to the pot, and bring to a simmer. Add the bay leaves, thyme, oregano, and Creole seasoning.
While the gumbo simmers, make the roux. Heat the I olive oil in a small saucepan over medium heat until it shimmers. Add the flour and whisk until it changes texture. Then shift to a wooden spoon (preferably one with a flat end)and stir until the roux reaches the color of pecans. Remove the roux pan from the heat.
Add a cup of hot gumbo to the roux and whisk it in. Then add about two-thirds of the roux mixture back into the gumbo and whisk it in. Add more warm roux, a little at a time, until the soup is the color and texture that seem right to you. (You might not use all the roux.)
Simmer the gumbo for about an hour. Taste and add salt, pepper, and hot sauce to taste. Just before serving, add the shrimp, crabmeat, crawfish tails, and/or oysters. Simmer until the seafoods are heated through--about two or three minutes. Serve with long-grain rice, garnished with the chopped green onions.
