Make the potatoes with skin in salted water, peel and quarter lengthwise. Fry the potato quarters in five tablespoons of oil until golden brown. Peel and chop the shallots and sauté in three tablespoons of oil until translucent. Scale the pike-perch, gut it, remove all fins, rinse and dry with kitchen roll. Score the fish six times about one centimeter deep on the back flesh. Push a bay seasoning into each of the cuts. Brush a baking sheet in the center with four tablespoons of oil, season lightly with salt, and place the pike perch on top. Brush the top side of the fish with four tablespoons of oil and season with salt. Cook the pike perch in the heated oven at 225 °C (convection oven 13 min. at 200 °C ) on the second rack for 18 minutes. In the meantime, cut the tomatoes into one centimeter thick slices and season with salt. Mix half of the chopped parsley with the chopped garlic and spread evenly on the tomato slices.
Mix the potatoes with the shallots and the olives, season with salt and season with pepper. Put the tomatoes and the potato mixture with the rosemary sprigs on the baking tray with the pike-perch and cook for another five minutes.
Sprinkle the remaining parsley on the tomatoes. Portion the pike perch and serve with tomatoes and potatoes.