Seafood is not the only natural resource harvested from the Gulf. You undoubtedly have noticed the offshore structures rising up out of the water. These are oil and gas production platforms, often referred to as oil rigs. There are several thousand such rigs in the northern Gulf of Mexico. The Gulf of Mexico routinely pumps more than one million barrels per day (bpd) of US crude, a quarter of the US domestic output and nearly 2 percent of global oil production. These structures house the workers and machinery needed to drill wells in the ocean bed to extract oil and/or natural gas and then deliver it to shore in a pipeline. The typical production platform is almost like a tiny city. It is self-sufficient in energy needs, housing, electrical generation, even recreation facilities for resident workers who work and live on the rigs for weeks at a time.This Louisiana coastline has a long history of extracting oil from the sea. In 1937 a fixed platform was first used to tap a field one mile off the Cameron coast. Just 10 short years later, the offshore drilling industry changed forever when a platform was constructed "out of sight of land" 18 miles off the Louisiana coast. This landmark event was important both psychologically and practically as it opened up a new frontier for exploration and production. The most common type of platform is the jack-up platform. A jack-up rig is a mobile platform that is able to stand still on the sea floor, resting on a number of supporting legs. The most popular designs use 3 legs, although some jackups have 4 legs or more. The jackup is usually towed (although some are self propelled) into location with its legs sticking straight up into the sky and the barge section floating on the water. Upon arrival at the drilling location, the legs are jacked down to the seafloor. Then the weight of the barge and additional ballast water are used to drive the legs securely into the sea bottom. Next, the jacking system raises the entire barge (including the drilling structure) above the water creating an "air gap", so that waves, tides and currents act only on the slender legs and not on the barge hull. Jackup rigs can generally be placed in water depths up to 400 feet. Louisiana's oil and gas industry has a value of more than 16 billion dollars. And the good news is that experts believe that large new oil deposits remain to be discovered in deepwater areas. Scientists have also found oil platforms to be havens for many species of fish. In the Gulf of Mexico, more than 200 old platforms have been converted to artificial reefs. Structures that provided oil and gas now produce another natural resource -- fish.