Shale gas is natural gas that is trapped inside shale rock and is extracted by using a technology called hydraulic fracturing, where highly pressurized water mixed with sand and chemicals is used to crack openrocks.
Boys and girls dive for sea urchins, cracking them open on the rocks before sucking out the innards - 'kina' or sea eggs are a muchloved delicacy among Maori people.
Specially formulated lubricants are used in fracking, which involves pumping water, fine sand and fracking fluids underground to split open oil- and gas-bearing rocks.