Without adding aeration, a lobster in a container of seawater quickly uses up the dissolved oxygen in the water and suffocates. Refrigerated trucks are ideal because they maintain the proper temperature and moisture. For best results, lobsters should be relatively cool before they are packed so that they are not stressed by going from warm to cold temperatures. Although lobsters are more successful at coping with temperature changes in the warm to cold direction, they aren't generally good at coping with rapid changes in temperature. It is also best not to feed lobsters for two or three days before shipping.
Full stomachs result in lobsters using more oxygen and increase the incidence of vomiting.
No need for messy lobsters. Shipping lobsters in airtight containers can result in carbon dioxide buildup leaving too little oxygen for the lobsters. However, pack the lobsters tightly enough that their shells won't get broken during shipping. Intact, healthy lobster's ship better than those with open wounds.