sentence: Fish is sold to their inland neighbors in exchange for products of the interior.
sentences_before: Trade contacts have been noted as early as 100 A.D. by early Roman writers who visited the East African coast in the first century. Trade routes extended across Tanzania into modern day Zaire. During the Middle Ages, ivory and slaves became a substantial source of income. Many slaves who were sold in Zanzibar ended up in Brazil, which was then a Portuguese colony. Swahili fishermen of today still rely on the ocean to supply their primary source of income.
concept_name: fish
headings: Swahili people Economy
categories: Ethnic groups in Africa Kenyan people Tanzania Mozambique