Thousands of anglers catch thousands of fish along our coast each year. And while more and more anglers are practicing catch and release, fish landed for a meal must be properly handled so they don’t end up in poor shape with no value as table fare. Anglers who have put in a good day on the water only to return home and find the day’s catch has turned to mush did not take the proper steps toward handling, processing and storing their catch.

Why Fish Spoil

Fish change after they’re caught. In fact, changes actually begin when a fish is hooked. The longer a hooked fish struggles, the more it depletes the energy reserve in its muscles. This, in turn, can cause undesirable changes in the fish’s fleshy tissue. For example, it may lose some of its natural sweetness and metabolic products can begin to accumulate, affecting its flavor and texture. To minimize this scenario, bring fish that are going to be used for food in quickly to reduce exhaustion.

Once a fish is landed and dies, an irreversible spoilage process begins. Spoilage is caused by several factors. Enzymes that normally regulate a fish’s metabolism remain active after the fish dies and can cause flavor and texture changes. Bacteria present on the surface, gills and in the intestines of living fish further diminish fish quality and eventually cause spoilage. Chemical changes caused by oxygen reacting with fat result in odors and flavor associated with rancid fish. The single most important factor in slowing this spoilage process is controlling temperature. Extensive studies of handling and processing of commercial catches have shown that there is a direct correlation between shelf life of a species and chilling the fish.

The Tuna Example

Tuna perhaps represent the best example of the potential for fish spoilage. Tuna are rapid swimming fish that migrate long distances and therefore require a constant and large supply of energy. In fact, tuna exhibit one of the highest metabolic rates of any fish. This metabolism generates body heat which for most fish is lost to surrounding water. However, in tuna a portion of the body heat is retained due to their unique counter-current circulatory system. A tuna’s veins and arteries are structured in such a way that cooler blood entering the muscle is warmed by coming in close proximity to naturally heated blood leaving muscles. Thus, tuna are capable of attaining body temperatures up to 18 ºF above sea water temperature!

During intense and prolonged fighting, a tuna’s metabolism changes to obtain stored energy. In a determined fish, enzymes and acids begin to break down or digest the fish flesh. As a result, the meat may become soft and mushy. In addition, the principal means of cooling in these fish is via blood passing through the gills and this cooling system ceases to function when the fish is removed from the water, resulting in rapid deterioration of muscle owing to elevated body temperatures. In terms of fish quality, elevated body temperature can enhance the onset and progression of spoilage by accelerating bacterial growth and chemical degradation.

Once a tuna is landed it is highly susceptible to spoilage. If left unchecked, a condition known as “burnt tuna syndrome” can occur. This condition begins when high temperature and acid wastes built up from overexertion by the live fish continue once the fish dies, resulting in the tuna actually cooking protein in its muscle. The flesh of the tuna affected by burnt tuna syndrome appears pale or cloudy and watery and has a sour to bitter taste and chewy or stringy texture making the fish much less desirable for consumption.

To overcome burnt tuna syndrome commercial fishermen, charter boat captains and big-game anglers have devised handling steps that are critical to maintaining and preserving quality and controlling the spoilage process that results in tuna burn. Although exact techniques vary, the aim of all handling procedures is the same:  to cool the fish quickly to prevent the onset of burnt tuna syndrome. Once landed, fish are generally stunned, killed, bled, gutted and dressed out in preparation for the chilling process. Chilling is accomplished with a brine slush solution of ice, seawater and rock salt or flaked or crushed ice. Fish are surrounded by the ice of choice and packed in chill boxes, chill tanks, fish boxes, coolers or fish bags.

Handling and Chilling Other Species

Since spoilage is a naturally occurring process after a fish dies, the quality of the fish you land depends on how far you let the normal spoilage processes progress. Thus, regardless of your quarry, proper handling and chilling of your catch can control the rate at which spoilage occurs and insure that maximum seafood quality is preserved.

Landing and handling the fish: All fish should be landed as carefully as possible, avoiding unnecessary gaffing, bruising, thrashing, or handling of the fish. Once landed, the spoilage process begins as bacteria and enzymes begin to work on the fish.

Bleeding and gutting the fish: If practical, bleed or gut fish to be kept by your preferred method as soon as they are landed. Removing blood from a fish retards quality deterioration and decreases cooling time. Bleeding can easily be accomplished by making a throat cut across the gills forward of the heart and immersing the fish in a bucket of water for about 10-20 minutes.

Gutting removes enzymes and bacteria that can contaminate edible tissue and accelerate spoilage. In most cases, fish can easily be gutted by making a smooth belly cut from the anal vent to a point between the gills. Once the cut is made, remove the entrails keeping them intact if possible. Make sure not to leave any blood or viscera in the body cavity. Finally, thoroughly wash or rinse the body cavity before storing.

When bleeding or gutting fish, always use a sharp, clean knife. If you can’t bleed and gut them right away, stun them with a sharp blow to the head and get them on ice.

Icing and Storage

This is the most important factor to insure good fish quality. As the tuna example illustrates, anglers can have the best quality fish by super-chilling their catch in a container like a fish box, cooler or other clean container. The better the insulation, the longer the ice will last and the colder the fish will stay. Ice cools fish quickly when fish and ice are in good contact. Ice also washes bacteria from a fish’s surface, keeps fish moist and prevents weight loss. Regardless of the type of ice and storage container you choose, maximum cooling is obtained by mixing fish and ice thoroughly in a manner that keeps the fish as close to 32 ºF as possible. Remember, temperature control is the key to slowing spoilage in fish!

Although there are a variety of forms of ice available, some types are superior for anglers. Crushed ice or flaked ice is your best choice because it allows a greater amount of ice surface to remain in contact with the fish and increases cooling rates compared to other types of ice. If fish are gutted, pack the gut cavity with ice to speed cooling.

If you are using crushed or flaked ice, your storage container should be set up to keep the fish out of the melt water. Start with a couple of inches of ice in the bottom of the container to provide a buffer area to keep fish out of direct contact with any fish-ice drippings that accumulate in the melt water and then simply layer fish among the ice. Periodically drain off the melt water if you are using an insulated cooler with a drain plug.

If you don’t have access to crushed ice or flaked ice, bear in mind that any ice is better than no ice!  However, large pieces of ice can crush, tear or bruise fish more easily than small pieces, so ice cubes or large blocks of ice should be broken up before use if possible. If uncrushed ice cubes or blocks of ice must be used, mix some sea water with the ice and periodically rotate or move fish around to avoid uneven cooling resulting from one side of the fish being in constant contact with the ice.

Once you’re home, decide how the fish are to be prepared or stored and dress out the fish accordingly. If you plan to store dressed out fish, they should be washed under cold running water. Refrigerated fish should be sealed air-tight in plastic bags or in other air-tight containers. If you plan to freeze your catch, wrap it air-tight in plastic freezer wrap, heavily waxed paper, or use plastic freezer storage bags. Label the packets with the species and date caught, and then place them in the freezer in a manner that allows air to circulate around them. Later, when thawing the frozen fish, do it slowly either in the refrigerator or under cold running water.

By using these techniques you will ensure maximum quality of your catch and enjoy Jersey fresh seafood. •