gems, pearl, Ceylon, Sri Lanka, Gulf of Manaar

Sinkankas: A monumental and exceptionally thorough biological and fisheries investigation of the pearl-oyster beds of the Gulf of Mannar, Ceylon, undertaken to understand the pearl oyster, its parasites and predators, associated organisms, and environmental conditions, with the practical aim of improving regulation and ensuring the long-term productivity of the ancient fishery. Although much of the work is devoted to detailed zoological descriptions and illustrations, it contains extensive material of direct gemological and historical interest. Part I surveys the history of pearl fishing, with particular attention to Ceylon, includes nineteenth-century production statistics, recounts Herdman’s expeditions, describes the principal banks, and examines the life history of the pearl oyster; a supplementary report treats the geology and character of the sea floor on which the oysters settle and grow. Part II gives histories of the principal banks, an anatomical study of the pearl oyster, and a detailed account of its parasites by A.E. Shipley and J. Hornell. Part III describes the 1904 fishery in considerable detail, including methods of fishing, handling oysters, and recovering pearls, illustrated with contemporary photographs, together with further discussion of parasites. Part IV covers the exceptionally productive 1905 “great” fishery. Part V is especially valuable for its statistics on pearl production, overall conclusions, and recommendations for conserving and regulating the fishery. Taken as a whole, the work is one of the most important scientific sources on the natural history, operation, productivity, and management of the Ceylon pearl fisheries.