Development in fish preservation and transportation has increased significantly the share of fish production that enters international trade. Fish is traded live, fresh, frozen, cured or canned. It is transported by sea, air or land. Live, fresh and frozen fish require special care in comparison with cured or canned fish.

Live fish

Transportation of live fish requires oxygen for respiration and removal of the toxic gases and by-products that accumulate, such as CO2 and ammonia. Certain fish, like catfish, can obtain oxygen through the damp surface of their gills or through the body skin. Other fish, like the climbing perch, have accessory air-breathing organs. But most finfish are transported live in water supersaturated with oxygen and kept at a temperature low enough to reduce their metabolism. Some tropical fish may not support temperatures below 10°C.

Fish is often starved (also called conditioned) before transportation to reduce its metabolism and increase the packing density. Crustaceans are transported live in wet packages using wet sawdust or other ways to keep the atmosphere surrounding the live animals humid and cool.

Transporting by air

Air cargo is responsible for transporting over 5% of the world annual catch and the increasing demand for fresh fish fuels a growing demand for air shipment of fish. However, successful air transport of fish and seafood requires special care in preparation and handling of the shipments, and excellent communication among the shipper, carrier and consignee. Also, it should be stressed that hubs often necessitate cargo transfers under tight schedules and the reliance on combination passenger-cargo, entry and exit in all markets can influence the timing of the delivery and the quality of the delivered products. But most importantly, the air shipment of improperly packaged fishery products is a safety hazard because of the potential damage, mainly by corrosion, to the interior and control mechanisms of the aircraft. Several companies spend yearly millions of U.S. dollars to repair damage that result from leaking seafood packages. Although ice is permitted to keep the fish cool, given it is sealed in plastic pouches, dry ice or gel packs are preferred by most airliners.

Transporting by land or sea

The most challenging aspect of fish transportation by sea or by road is the maintenance of the cold chain, for fresh, chilled and frozen products and the optimisation of the packing and stowage density. Maintaining the cold chain requires the use of insulated containers or transport vehicles and adequate quantities of coolants or mechanical refrigeration. Continuous temperature monitors are used to provide evidence that the cold chain has not been broken during transportation.

Excellent development in food packaging and handling allow rapid and efficient loading, transport and unloading of fish and fishery products by road or by sea. Also, transport of fish by sea allows for the use of special containers that carry fish under vacuum, modified or controlled atmosphere, combined with refrigeration.