Preheat the vegetable oil in a skillet and saute the aromatics, which are tarragon, parsley, fennel, celery, garlic, leeks, and onions. Cut the vegetables into very thin slices and tie the bay leaves in a string.
Add the white meat fish scraps to the mix and mix it around.
Turn on the stove and pour 7 – 8 quarts of water in it, then boil it on high heat.
Add 1/2 cup of white wine to the aromatics. Make sure that the wine or water fills the skillet so that it almost covers the fish scraps and cook for 1 – 3 minutes.
Once done, pour the aromatics and fish scraps into the 8 quarts of water that you’ve boiled earlier and add 1 – 2 tbsp. of soy sauce, 1 tbsp of sugar and 1 tsp of mirin. Let it simmer for 1 hour.
After you’ve let it simmer for an hour, the fish broth substitute for dashi should be ready.
Strain the mix, put it in a glass container, and refrigerate it. You can store it in the freezer for up to a month before you use it.