Mackerel swim in schools, too, so all of a sudden everyone will be catching and reeling one in, and it's a flurry of activity trying to get the flopping fish off the hook and into your cooler, without getting a hook stuck anywhere. Between the six of us, we must have caught 75 or more. Some were small (and we had more than enough), so we ended up donating a ton to the boat for bait for another trip, and we also tossed some back overboard. Our coolers were overflowing.
We had the crew take the heads, tails and guts out, and Mark and I ended up spending hours when we got home, grilling and then trying to de-bone them all, which was a painstaking process. We quit on a lot of the fish because they just had too many tiny slivers of bone that were impossible to get rid of. I peeled and boiled a bag of potatoes and sauteed onions and made a ginormous pot of fish stew, half of which is frozen for later.