Optimum Cooling and Storing for Live Fish

One of the challenges of working with fish and seafood is the need to keep the day’s catch from spoiling before it reaches its destination. Once it has died, a fish deteriorates quickly, diminishing in quality, flavor, and nutritional value. Ice storage is a popular method for keeping fish fresh on their way to market or the table. However, this is not the only way to maintain quality. With the right equipment fish can be kept alive through the duration of their journey, arriving at their destination in prime condition for maximum freshness and flavor. Many vendors keep tanks on the premises so fish can be kept alive and on display until a buyer makes a purchase. In this way consumers can enjoy fish that was caught half way around the world but that has been dead for less than a few hours.

Live shipping also allows tropical varieties to be shipped around the world. It is especially important that these delicate species be transported with the greatest of care in order to assure they arrive at their destinations in good health. SEMCO/SEMCOLD LLC manufactures and installs customized industrial cooling systems that allow commercial fishermen to transport live fish at the optimum temperature to maintain their freshness and vitality. There are several important points to consider when transporting live fish.

Fish Must be Healthy

Fish must be healthy and whole. For the most successful transportation, robust fish should be kept in clean, fresh water where the temperature and oxygen levels can be controlled and the water can be continuously filtered. Sick or damaged fish should be removed to prevent them from contaminating the rest of the catch.

Fish Should be Transported with Reduced Metabolic Rates

Fish should be starved to reduce their metabolic rate and conserve oxygen. Fish with a full digestive system do not transport well. Recently fed fish will require more oxygen, are more sensitive to stress and can contaminate their water with excrement. Starved fish can be transported twice as far as those that are not. Fish should be left for at least a day without food in order to clear the digestive tract. There is one caveat to this advice; fish in the larval stage require food at more frequent intervals. Herbivorous varieties should not go without food for more than 20 hours, while some aquarium species may require feeding in less than 12 hours.

Fish Must be Kept Cold

Fish should be kept in cold water. A low water temperature slows a fish’s metabolism and maintains a relatively high pH level. Fish are much more active at higher temperatures and consume oxygen quickly. They also metabolize more quickly and produce more waste. These factors reduce the availability of oxygen in the water and reduce the time and distance that a fish can tolerate being in transit.

Fish Mustn’t Have Their Systems Shocked

The water should be cooled gradually to avoid shocking the animal’s system, particularly during the summer months when they are accustomed to warmer temperatures. Cold-water fish should be transported at 6–8°C in the summer and 3-5°C in the spring and autumn, while warm-water varieties should be kept at 10-12°C in the summer and 5-6°C in the spring and autumn. In the winter both varieties should be stored at 1-2°C. Fish have different needs depending on the variety.

Different Species Have Different Requirements

Different fish require different densities. For a shorter transport lasting only one to two hours with water at an optimum temperature large varieties can tolerate fish to water ratios of 1:1 to 1:3, but smaller varieties require much more water. Some thrive only at fish to water ratios as low as 1:200. Smaller fish require more oxygen and space per individual. The longer the journey is, the more water per fish is required. Higher water temperatures also decrease the total volume of fish that can be transported in a single trip. In order to transport more fish, it is necessary to keep temperatures low.

As a food commodity, fish is very perishable. However, modern transportation tanks equipped with industrial cooling systems like those manufactured by SEMCO/SEMCOLD LLC can enable fishermen to keep their catch alive and healthy on long transportation routes. Consumers often pay a premium for the freshness of a live fish. Please contact us to discuss the best live fish cooling and storage system for your needs.