Sea Creatures 101: The Life of Your Seafood: Tuna

Oh, I can hear the groans now-TUNA?? How common! She must be running out of ideas! Well, the ideas CAN run a little thin sometimes, but when you think about it, what do you know about tuna? What kind of life does a tuna live? How did it become such a common food fish?

Let’s start with the life of the tuna first. Tuna are pelagic fish, drifting and following ocean currents. The currents in the ocean act like rivers, allowing the tuna to travel to places that are best suited for food and reproduction. When tuna is ready to mate, it will swim through these rivers of current from deeper waters to reach open ocean or shallow coastal water, usually during August or late September. During spawning, a female lays her eggs in open water and a male releases sperm in the water near the eggs, fertilizing the eggs. After that, the baby tuna develop on their own without parental help. The eggs hatch in about 24 hours and the little tuna drift with the current. These tiny fish are easy prey for other fish. Out of a possible 6,000,000 eggs in a single spawning, about 2 of the little tuna will make it to adulthood.

Tuna are built for speed. The body is streamlined. The tail is sharply forked, and the tendons in it connect it to the swimming muscles, providing strength and force. The vascular system of the tuna keeps its body temperature above the water temperature. This helps to speed nerve impulses and increase power in the muscles. The bright blue on top of the body and the gray-silver spotting on the bottom helps in camouflage. What do tuna eat? They arent that picky-lobsters, crabs, shrimps, and barnacles. Clams, snails, oysters and mussels, and even each other.

There are five general types of tuna: bluefin, yellowfin, bonito, striped (also called skipjack), and albacore. Bluefin tuna is the largest, weighing up to 18008 lbs. It can be found in the Atlantic and Pacific oceans, Mediterranean Sea, and the California coast. Yellowfin tuna are found in the Atlantic and Pacific, and near Florida and Rhode Island. Bonito (sometimes called Bonita) grows to 6 lbs and lives in the Atlantic Ocean. It is often fished in Nova Scotia and Brazil. Striped tuna gets up to about 50 pounds. And can be found in the Pacific. Albacore, or chicken of the sea, travels around a little more- migration is between the U.S. and Japan.

We can thank sardine canners for the idea of canned tuna. In 1903, sardine canners in California were looking for a new fish product to can. It was accessible and inexpensive. Then came soup. Campbell’s soup decided to market a new recipe featuring tuna on the back of their mushroom soup cans over 50 years ago. Tuna casserole was born! Statistics state that on average, Each American eats 4 lbs of tuna every year. (I don’t think I am one of them, but anyway..) Europeans enjoy tuna on their pizza. Albacore tuna has been called the chicken of the sea because of its white color, drier texture, and taste. Of course, we know that EVERYTHING tastes like chicken, but that is the idea behind the phrase. There is more to tuna than food. However- the oil from its liver is used in the processing of leather.

There are two hot topics associated with tuna as a food fish. The first one pops up now and then- methylmercury in tuna. This type of mercury is common in many fish, especially saltwater fish, but canned tuna has just trace amounts of it. A person would have to eat 25 times the typical per-person amount per year to cause a health concern. There may be some individuals who eat tuna exclusively, but they are in the minority. The other controversy is about how tuna is fished. Around 1960, the tuna industry began to use a technique called “fishing on the dolphin.” Yellowfin tuna are often found swimming with spotted dolphins. When the fishermen see the dolphins come up for air, they drop a long net down and catch the tuna and dolphins. The dolphins get trapped in the net and cannot come up for air so that they can asphyxiate from lack of oxygen. In 1972 the Marine Mammal Protection Act was passed. Some tuna processors are using other ways of fishing for tuna, and will often note that on their packaging. Look for the dolphin-safe tuna label.

As I researched this article, I was amazed at the information available on tuna. If you would like to explore this further, here are just a few links. I know that you will find more.

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