Great white shark biology: Great white sharks are thought to be sexually mature at about 3m for males (8 years) and 3.5m for females (12-13 yrs). The gestation period is thought to be between 14 to 18 months, and between 2 and 10 juveniles are born live at around 1.3m in length. The life span of the great white shark is thought to be 30-40 years, although recent studies using radiocarbon analysis have determined age estimates of up to 73 years, showing the species to be even more vulnerable than previously thought. Recent estimates from a study by Sara Andreotti would seem to support this, suggesting there are less than 600 great white sharks that visit the country’s southwest coastline between Port Nolloth and Port Elizabeth. Globally the numbers of great white sharks are thought to have dropped by nearly 80 percent in the 20 years between 1986 and 2006.Great white shark behavior: Great white sharks feed on other sharks, seals, bony fish, turtles, large rays and dolphins, they are also known to scavenge on dead whale carcasses. Surprisingly, some research indicates that seals may only comprise 20% of the diet. Great white sharks are without doubt the most globally feared of all shark species, however they may often be wrongly implicated in attacks on humans – especially in warmer waters where Zambezi (bull) and tiger sharks are also possible culprits. Great white sharks can be found in all temperate and tropical waters worldwide. Often sighted close inshore, the larger sharks will seasonally congregate around seal colonies between extensive migrations. In February 2004 a tagged female white shark of 4m, named Nicole, surprised everyone with a transoceanic migration of over 11 000 km from South Africa to W. Australia. Nicole then completed the round trip in just over nine months when she was sighted again off Dyer Island, South Africa, in August 2004. Sightings of great white sharks in open waters off South Africa are rare, however a booming cage diving industry has developed around the seal colonies of Cape Town, Mossel Bay and Gansbaai.
BLUE SHARK – Prionace glauca. Identification: The blue shark is a slender, elongate shark that may attain a length of 3.8 m. The body of the blue shark is