How to See a Blue Shark

Among the world's most common sharks, the blue shark (Prionace glauca) can reach speeds of at least 25 mph, making it one of the fastest sharks. Blue sharks migrate up to thousands of miles in a few short months. Follow these steps to learn to recognize blue sharks.

Difficulty: Moderately Challenging

Instructions

1. Locate blue sharks in open waters, typically far out to sea but occasionally closer to the coast. They inhabit all temperate and tropical seas from 55 degrees F and above.

2. Identify the blue shark as a large, sleek shark, growing up to 13 feet long. It has an indigo upper body with bright blue sides and an off-white belly.

3. Notice the shark's pointed snout, large, circular eyes and long pointed pectoral fins. Blue sharks have five gill slits, a larger first dorsal fin than its second dorsal fin and an elongated caudal or tail fin. The blue shark receives its powerful swimming motion from the side to side movement of its tail.

4. Note the narrow lower jaw, lined with pointed, serrated teeth. The blue shark's teeth allow them to catch slick squid and fish.

5. Learn their social habits. Blue sharks school in large, same-sex groups with sharks roughly the same size.

6. Know their reproductive cycles. Blue sharks are viviparous, meaning they birth live young. Depending on the mother's size, litters range from four to 100 young.

Tips & Warnings

• Blue sharks look similar to Shortfin Mako sharks. Distinguish the blue sharks by their serrated teeth, smaller gill slits and longer pectoral fins.
• Each year, blue sharks migrate along the Gulf Stream from the Caribbean Sea, up the eastern U.S. coast, over to Europe then down the African coast and back to the Caribbean.
• These sharks provide popular sporting fish with anglers and commercial fishing boats, which catch an estimated 20 million per year.
• Be careful diving in open waters as blue sharks can be aggressive and attack people.

Resources

• Visit elasmodiver for dozens of shark photos.