Gut, clean and wash the mackerel. Cut lengthwise, remove the backbone, an incision on the diagonal, sprinkle with lemon juice, sprinkle with a pinch of pepper, spread on top tarragon. Scald the tomatoes, remove the peel. Grind the peeled garlic. In the a large skillet, fry the garlic until transparent, add the tomato, pepper, salt and basil. Mix wine with green pepper, pour the tomato, spread the mackerel on top. Simmer, covered for 10-15 minutes.