Thai workers pull tuna into nets in the hold, where the temperature is minus 22 degrees Celsius. The large ship is docked just outside Bangkok and will spend one week unloading hundres of tonnes of tuna.&amp;nbsp;Each frozen skipjack carcass weighs about 40 kilograms (88 pounds); one ton of skipjack fetches about $1,600 on the wholesale market.  Samut Prakan, Thailand