The floating water of Spanish mackerel fishing at sea. Spanish mackerel fishes in the upper layer of water, with a distance of 1.5-2.5m, a water depth of about 6m and a distance of 2-3m. In addition, with the increase of Spanish mackerel size, the water layer in which it lives will be lower and lower. When fishing Spanish mackerel, it is necessary to adjust the waterline length by moving the line blocking knot, and constantly look for the water layer with Spanish mackerel, so it is impossible to fish at the same depth all the time. When the ocean current is large, the part below the hook line will be washed up, resulting in the actual fishing shed can only float into the water. According to the size of ocean current, the amount of lead biting should be appropriately increased or decreased to control the sinking depth of hook bait.