The Blue Shark Prionace glauca 

The blue shark is one of the most attractive and graceful of the world’s sharks. With its indigo blue colouration, it is also one of the easiest species to identify. It is often seen at the surface, particularly in higher latitudes, with its pectoral fins outspread and its first dorsal fin and upper caudal lobe out of the water.

They are mainly an open ocean shark, and are found in temperate to tropical waters world wide. They are the most wide spread of the sharks, but some stocks are seriously reduced by over fishing.

Blue sharks are great travelers and many individual sharks tagged by researchers have been discovered thousands of kilometers away, sometimes only weeks later. Little is known of their migrations. At higher latitudes populations tend to be migratory, but lower latitudes populations are mainly migrant.

The danger to divers is potentially high risk, however many encounters are organized for divers without incident. (These sharks have been blamed for feeding frenzies on survivors of ships sinking during the 2nd World War, and sailors would even claim that they would appear alongside ships when someone had died.) Blue sharks have an uncanny ability for turning up at the right place at the right time especially floating carcasses of dead whales.

Identification Checklist

• Large size
• Metallic or indigo blue upper side, bright blue sides, snowy white underside
• Slender body
• Exceptionally long, narrow, pointed pectoral fins
• First dorsal fin well behind pectorals
• Second dorsal fins about half the size of the first
• Scythe like tail
• Long conical snout
• Large round eyes centered within a white ring