Melt the butter in a medium pot over medium heat. Add the onion, garlic, celery, carrot, red pepper, and fennel and cook for 3 minutes, stirring often. Reduce the heat to low and add the flour, cumin, coriander, and cayenne pepper. Cook for 5 minutes, stirring often. Increase the heat to medium-high and stir in the fish stock a third at a time. Once it comes to a boil add the corn, reduce the heat to a simmer and cook for 5 minutes. Add the crabmeat, cream, lemon, parsley, and salt. Cook for 2 more minutes. Serve immediately.