The relationship between technological development and socioeconomic change in the maritime fishing industry of the Sierra Leone Peninsula from 1600-1980 is explored in this paper. Positing that technological development in Africa derives from several interrelated factors such as existing techniculture, appropriate natural resources, and tradition, the paper cites documentation to show that a maritime techniculture, as well as the knowledge to use it for economic purposes, existed among several ethnic groups in the Sierra Leone Peninsula prior to the colonial period, which began around 1800. A case study of the fishing village of Tombo, founded at that time, is used to illustrate the process. The study reveals that the village had an essential capacity to change its social relations while at the same time adopting, for economic reasons, new technologies and fishing methods introduced by immigrants. Prior to the introduction of modern technology by the Fante fishermen from Ghana in the 1950's, Tombo's economic development was only partly restricted by its simple techniculture; also inhibiting development was the general underdevelopment within the Colony and the Protectorate, particularly poor roads and poor consumer purchasing power. A 3-page bibliography (1745-1984) is appended. (Author abstract, modified).