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the Legacy continues…………………….
Gregory R. Mann, Ph.D. {ret.}

Blue Shark

“Prionace glauca”

Blue Sharks are large slender, blue-indigo-colored sharks. Blue Sharks are found in very deep waters. They prefer cooler water though so they are often found in sub tropical areas where it doesn’t get too warm. It isn’t very often you will see one unless you are diving in the depths of the ocean. Most divers are well aware of what a Blue Shark looks like and strive to stay as far away from them as possible. From time to time, you may see a Blue Shark leap out of the water. They enjoy doing this in order to see what types of foods are on the surface for them to dine upon. They are extremely fast swimmers and so it can be hard to track them. Blue Sharks swim long distances in order to follow the food sources and they don’t have any set habitat area that they continually return to. They have been known to move thousands of miles in the water in the span of very little time. In addition to looking for food it is believed they do this for mating purposes as well. Blue Sharks are considered to be dangerous and so people are warned to steer clear of them. They have been involved in numerous attacks on people and some of them have resulted in death due to the force of the jaws and teeth that this species of shark has. They are one of the few species of sharks that stick together in small groups. They have their own hierarchy that is determined by various factors including the sex and size of each member. They are hosts to various types of parasites that live in the water as well. Blue Sharks tend to have quite a healthy appetite. Their favorite food is squid but it isn’t always readily available. They will eat fish, mollusks, small sharks, seabirds and even garbage they find floating around in the water. On average, a Blue Shark will grow to be 12.5 feet in length. They don’t weight much compared to other sharks at a maximum of about 450 pounds. They have a very slender body so many people mistake adult blue sharks for young of other species. They range in color from a light blue to a deeper shade of it. They may have several shades of blue on their bodies with the darkest colors on the top.

Blue Sharks are pelagic (found in open waters). Like most pelagic sharks, they are found worldwide. They migrate east across the Atlantic Ocean each year, following the warm Gulf Stream waters. They travel a circuit from the Caribbean Sea, along the coast of the US, east to Europe, south to the African coast and back to the Caribbean. Blue Sharks often form large, all-male or all-female schools which contain sharks that are about the same size; the reason for this unique social behavior is unknown. Blue Sharks are opportunistic feeders; however, their favorite meal is apparently squid. Blue Sharks are viviparous, the young are born live rather than from an egg. Litters consist of 4-135 pups; the number of pups increases as the size of the mother increases. Their gestation period is almost 1 year. Females are mature at 5 years of age. Blue Sharks are known to live for at least 20 years. The mating ritual for Blue Sharks is very interesting. Some researchers watching this normal ritual, may consider the male to be extremely aggressive. He will be biting hard on the female but it doesn’t hurt her. The skin of females is three times thicker than the male. The biting is done to allow the mating to be completed. It is a type of grip so the two don’t separate before the sperm has been placed inside of the female. A litter of Blue Shark pups can be from 4 to more than 130. They are viviparous and the pups are immediately left to take care of themselves once they are in the water and out of their mother’s body.

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