Skipjack tuna is a medium sized fish with a distinguishing black strip from behind its back to the tail. Found abundantly in most parts of the world ocean, skipjack tuna has dominated the world tuna market. It is marketed fresh, smoked, salted and canned.
Skipjack Tuna is also known as victor fish, aku, arctic bonito, striped tuna, mushmouth and Oceanic bonito.
Skipjack tuna grows up to a length of 1m and they weigh around 18kg. Similar to other tunas, skipjack tuna has a spindle-shaped body and is mostly without scales. It has two dorsal fines, one with the spines and one without it. Several finlets follow the second dorsal fin. The anal fin is just beneath the second dorsal fin and is followed by finlets. The posterior peduncle consist of three keels; the larger one between the two smaller ones.
Picture 1 – Skipjack Tuna
The skipjack tuna fish has a distinguishing dark lines extending towards the tail from behind the corselet back. They have a silvery lower flank and belly. It has a deep purplish blue back. Their teeth are conical in a single row.
Skipjack tuna are found in the tropical and sub-tropical seas. They are found in the tropical Atlantic south to Argentina, at the coast of Europe and throughout the North Sea. Skipjack tunas are migratory and are also found in Pacific, Indian and Atlantic Ocean.
Skipjack tuna are pelagic species which live in open Ocean. They swim near the surface during the day and descend to depths at night. They form a school based on their size along the drifting object or whales and sharks. Schools of skipjack tunas are often found at the convergence of warm and cold water.
Skipjack tuna reach their sexual maturity in about a year when they are 40cm in length. They spawn throughout the year in the equatorial waters. The female lays eggs depending upon its size and are capable of laying around two million eggs a year. The eggs are pelagic and move to the cooler waters along with the ocean current.
Skipjack Tuna have a life span of about 7 to 12 years.
Skipjack tuna are highly migratory. They originate at the equatorial water and migrate towards north and south forming a school associating either with drifting objects or whales and sharks.
Skipjack tuna primarily feed on fishes, mollusks, lantern fish, cephalopods and crustaceans. This fish feeds near the surface and their diet mostly consist of squids, shrimps, small mackerel, herring, sardines and anchovies. This species has cannibalistic nature. Skipjack tuna are active in foraging during dawn and dusk and are mostly found near convergences of varying temperature due to availability of abundant food supplies.
Skipjack tuna fall prey to larger fishes such as billfish, sharks, larger tunas, wahoo and yellowfin tunas. Seabirds and humans also prey them down. Skipjack tunas are cannibalistic in nature.
Importance to Humans
Skipjack tunas are found abundantly in many parts of the world’s ocean. In recent times, skipjack tuna has dominated the tuna market. The speed at which they mature and reproduce has lead to a large scale commercial and recreational fishing of skipjack tuna. Skipjack tuna is sold fresh or frozen and is also one of the common canned tunas. It is common in one of the raw fish dishes. Dry skipjack tuna are popular in Japan and is known as “katsuobushi”.
Picture 2 – Skipjack Tuna Picture
Skipjack tuna is a good source of:
Skipjack Tuna is a very nutritious food. It is a rich source of protein, potassium, manganese, Vitamin B1 and B6 and essential fatty acids.
Increases the omega-3 level which is beneficial in maintaining cardiovascular health. It increases the good cholesterol, controls the heart rhythm thereby reducing the risk of blood clotting in the arteries.
It is an excellent source of Vitamin B6 and Folic acid. It helps lower the level of homocysteine which is responsible in damaging the artery walls.
It helps in increasing the Heart Rate Variability (HRV), thus reducing the risk of arrhythmia.
Helps maintain lower blood pressure.
Reduces the risk of stroke.
Provides cardiovascular protection to women with diabetes.
Reduces the risk of asthma on children
Skipjack tuna, a source of omega-3 has the ability to protect our skin from sunburn.
Helps to detoxify the body. Omega-3 and selenium is a very important anti-oxidant which helps to cleanse the body of harmful compounds, drugs and pesticides.
Protection against ovarian and digestive track cancer.
Beneficial in protection against kidney cancer
Help maintain memory decline and Alzheimer’s diseases
Skipjack tuna rich in Omega-3 helps reduce depression
Skipjack tuna has rich meat and strong flavor. They are canned, smoked, salted and dried. Here are some of the recipes for skipjack tuna:
Tuna and Macaroni salad: macaroni, canned tuna, capsicum, mayonnaise, dill seed and celery
Tuna pasta with tomato and garlic: cooked pasta, canned tuna, garlic, tomato, chili, kalamatta olives, chopped parsley
Tuna with bean salad: tuna, beans, cracker pepper, onion and vinegar
They are mostly found in convergence zone where the warm and the cold current meet.
It is a light meat fish which is usually canned and also marketed fresh, frozen, dried, salted and smoked.
Skipjack tunas are low in calories.
Skipjack tuna is rich in protein, three times more than egg
It is low in fat
It is low on carbohydrate hence can be taken during weight loss program.
It is rich in minerals.
Skipjack tuna are not considered as an endangered species. According to the World Conservation Union Redlist, skipjack tuna do not fall under immediate threat. However, skipjack tuna in Atlantic Ocean has been showing a decline over the recent years. Harvest and import of the skipjack tunas are regulated by the National marine Fisheries Service.