In a heavy pot, bring the water to a rolling boil. Reduce heat to simmer. In a separate pan, heat the oil. Add the garlic and sauté 5 minutes on low heat. Remove the garlic and discard. Add the onion and sauté 7 minutes. Transfer the onion to the simmering water. Cook 20 minutes, then stir in the crab meat. Simmer an additional 2 minutes, then add the bitter orange and lemon juices. Serve immediately. This soup can be refrigerated and reheated.