Filets de Maquereaux à la Sauce Escabèche

mackerel fillet 56.0% , water 11.2% , vinegar 11.2% , sunflower oil 11.2% , dehydrated onion 1.6% , tomato concentrate 1.8% , shallot 1.6% , garlic 0.6% , salt 0.6% , parsley 0.3% , natural flavouring 0.0% , gomme guar **Scomber scombrus 0.0%