Cut the yellowfin tuna filleted loins in gallon-size-bag chunks with the skin still on. Place skin side down, then meat to meat to prevent the skin from touching the tuna meat. Seal the bag air-tight and get it cold immediately. Layer the cooler with ice, meat, ice and so on. If it will be in the cooler for a while, pull the plug on the cooler to keep water off the tuna steaks in case the bags don’t hold. You don’t want to ruin the ahi tuna by having it sit in fresh water.