The Great Hammerhead is the largest species of Hammerhead Sharks. They are about 11 feet long and weigh around 500 pounds on average with some of the largest specimens weighing over 1,000 pounds. The longest great hammerhead was recorded reaching 20 feet long.
Although the great hammerhead is a species of fish, it has has a viviparous mode of reproduction, which means the female gives birth to live young. Mothers can birth litters of up to 50 pups from different fathers, however despite the ability to produce so many young, these sharks are critically endangered.
Why do they matter?
Being an apex predator, the Great Hammerhead plays an essential role in coastal marine ecosystems. By preying on species below them in the food chain, great hammerhead helps ensure the species diversity as well as keep balance with its competitors. Apex Predators, like the Great Hammerhead also ensure that diseased and injured individuals from their ecosystems are removed and therefore, helps to keep the ecosystem healthy.
Great Hammerheads are particularly threatened by the global shark fin trade because of the large size of their fins.
As human implemented ways for large-scale fishing, the number of great hammerheads dropped drastically. Researchers estimate that there has been a drop of up to 50% in Great Hammerhead populations over the last three decades. Furthermore, as Great Hammerheads migrate during summer, it allows illegal fishing to take place in international waters where there are few patrols and governments have less control.
Will climate change affect the great hammerhead? Yes.
According to the 2013 International Panel on Climate Change(IPCC) report, a further 2.6 – 4.8 °C will rise by 2100 due to changes in climate. This presents an extreme challenge for highly mobile marine animals, including the Great Hammerhead. Most sharks are ectothermic, meaning their body temperature depends on the external environment as they cannot generate their own body heat. These changes in water temperatures coupled with the Great Hammerhead’s high specificity for suitable water conditions, may result in disastrous consequences for the Hammerheads in terms of prey availability as well as migratory patterns.