Cecil von Bonde's parentage is uncertain, but he was probably the son of Gerhardus Cornelis von Bonde and his wife Magteld Cornelia Maria de Kock. He matriculated at the Normal College Boys' High School, Cape Town, in 1912, continued his studies at the South African College, Cape Town, and was awarded the Bachelor of Arts (BA) degree by the University of the Cape of Good Hope in 1916. In January 1918 he succeeded W.K. von Bonde* as lecturer in zoology at the College, which that same year became the University of Cape Town. After qualifying as Master of Arts in 1918 and being appointed as senior lecturer in zoology that same year he continued his studies in zoology under J.D.F. Gilchrist* and was awarded the degree Doctor of Philosophy (PhD) in zoology by the University of Cape Town in 1923. His doctoral thesis dealt with The zoogeographical distribution of the Heterosomata [flat fishes].
Meanwhile he cooperated with Gilchrist in compiling treatises for students on Dissection of the platana and the frog (1919, 46 pp.) and Practical zoology for medical and junior students (1922, 329 pp.) He published some papers in the Reports of the Fisheries and Marine Biological Survey in which he described the flat fishes (1921), shallow water fishes (1923) and skates and rays (1923) caught by the marine survey vessel Pickle, as well as "A method of tagging marine fishes with a view to tracing their migration" (1928). His other publications included a paper in which he described "Heterosomata from Portuguese East Africa" (Transactions of the Royal Society of South Africa, 1925), a textbook on Comparative zoology: An introduction to the study of comparative anatomy, comparative embryology and taxonomy (Cape Town, 1928), a Report on a preliminary survey of the sea fisheries of Kenya Colony (Nairobi, 1928), a Report on a preliminary survey of the marine fisheries of the Zanzibar Protectorate (Zanzibar, 1929), three papers dealing with "Contributions to the morphology of the elasmobranchii" [cartilaginous fishes] (Journal of Comparative Neurology, 1933), reports on his Studies in the canning of the Cape crawfish, kreef or spiny lobster (Pretoria, 1935, 43 pp.), The reproduction, embryology and metamorphosis of the Cape crawfish (Pretoria, 1936, 25 pp.), and a Textbook of physiology and hygiene for South African Schools (with P. de Villiers, 5th ed., Cape Town, 1949). His last book, So great thy sea, was published in 1956.
Von Bonde was a conscientious worker, interested mainly in marine biology, but inclined towards a practical rather than an academic approach to his subject. During 1924-1925 spent two semesters at the University of Liverpool, where he studied oceanography and lectured in zoology. In 1926, after Gilchrist's death, he became acting head of the Department of Zoology until the appointment of Lancelot Hogben in 1927. Von Bonde left the department in 1928 to become the first full-time director of the Fisheries and Marine Biological Survey (which later became the Division of Sea Fisheries), a post he held until 1952. From 1945 he was also a director of the Fisheries Development Corporation of South Africa, Ltd., and its managing director from 1953 to 1960.
In 1928 he was seconded to conduct fisheries and marine biological surveys in Kenya and Zanzibar. The next year he represented South Africa at the International Conference on Oceanography and Continental Hydrography in Seville, Spain. He visited fisheries and marine biological laboratories in the United States and Canada on a Carnegie Grant in 1932 and in 1937 went to several European countries and to North America. In 1946 he attended a conference of the Food and Agricultural Organisation (FAO) in Copenhagen, Denmark, and served on its Standing Advisory Committee of Fisheries. He was appointed as International Whaling Commisioner in 1949 and later chaired the Whaling Technical Committee.
Von Bonde played a major role in the development of the fishing industry, especially the pelagic shoaling fishery, and in research in South African marine resources. He saw the marine environment as a national resource threatened by over exploitation and urged state intervention to safeguard it. He also pointed out the importance of a practical marine science to guide such intervention. Under his direction the Marine Biological Survey sought to extend its control over both the marine resources and the fishing industry through the collection of reliable statistics, enforcement of conservation legislation, and reorganisation of production into co-operatives and marketing cartels.
Von Bonde was elected a Fellow of the Royal Society of South Africa in 1935 and also became a Fellow of the American Association for the Advancement of Science. He was a member of the South African Association for the Advancement of Science, serving as president of its Section D in 1931. His presidential address dealt with "The correlation between marine biology and the problems of the fishing industry" (South African Journal of Science, 1931, Vol. 28, pp. 42-50). In 1920 he became a member of the South African Biological Society, was also a member of the American Society of Ichthyologists and Herpetologists, and a Fellow of the International Biographical Association (London). Among the awards he received were the Purcell Memorial Prize for Zoology of the University of Cape Town (1926), the King George V Jubilee Silver Medal (1936), and the King George VI Coronation Silver Medal (1937).
Von Bonde retired to Knysna in 1960. He married Marjorie Leibrandt in July 1922.