Heat fat or oil in a large stock pot over medium heat. Sauté fennel, onion, and celery in the coconut oil for 5-10 minutes until fragrant.
Add the broth, turnips, bay leaves, thyme, salt, and mace. Stir and bring to a boil. Reduce heat and simmer until turnips are tender. Remove bay leaves.
Using a hand blender, pulse chowder a few times to refine consistency, if desired.
Add cod. Cover and simmer for 5 minutes.
Add remaining seafood and coconut milk. Simmer uncovered for about 2 minutes until everything is cooked (but not overcooked and rubbery!).