Storage: Store mackerel fillets in the coldest part of your refrigerator.
Shelf Life: Up to five days.

Mackerel can be grilled, broiled, smoked, poached, roasted or added to soups. For firmer flesh, marinate it in acid (citrus juice or vinegar) before cooking.
Mackerel’s distinctive flavor pairs well with allspice, cloves, chilies, citrus, vinegar, ginger, scallions, saffron threads, and most fresh herbs.
How to Remove Fish Skin (if desired)
Fish Fillet Recipes & Techniques