Gilaks (Gileki: گيلکؤن, Gilek'ha) are an Iranian ethnic group native to the south of Caspian sea. They form one of the main ethnic groups residing in the northern parts of Iran. Gilak people, along with the closely related Mazandarani people, comprise part of the Caspian people, who inhabit the southern and southwestern coastal regions of the Caspian Sea. They speak the Gilaki language, an Iranian language that is closely related to Mazandarani. Gilaki people live both alongside the Alborz mountains, and in the surrounding plains. Consequentially, those living along the northern side of the Alborz mountains tend to raise livestock, while those living in the plains farm. Gilaks play an important role in provincial and national economy, supplying a large portion of the region's agricultural staples, such as rice, grains, tobacco, and tea. Other major industries include fishing and caviar exports, and the production of silk. In addition to agricultural activities, Gilaks also control other principal sectors of commerce of the province of Gilan such as tourism, and share administrative and government positions with civil servants from other regions of Iran. The population of Gilaks is estimated to be between 3 and 4 million (2006 estimation). They mainly live along the southwest coasts of the Caspian Sea and are one of the main ethnic groups that reside in the northern parts of Iran. The Gilaks are closely related to the neighboring Mazandarani, and other groups of Caucasus descent, such as Georgians, Armenians, and Azerbaijanis. Gilaks make up approximately 70% of the population in Gilan province. Gilaki, which has two main dialect types, eastern and western, with the Safidrūd River as the general border, is a member of the Caspian subgroup. There are many subdialects of Gilaki, and, progressing to the east, it gradually blends into Mazandarani. The intermediate dialects of the area between Tonokābon and Kalārdašt serve as a transition between Gilaki and Mazandarani.