From fisheries research to fisheries science, 1900-1940.The Bergen and the ICES scenes: tracing the footsteps of Johan Hjort.
reportposted on 2022-03-01, 08:56 authored by G. Sætersdal
The period 1900-1914 has been termed the golden age of Norwegian fishery investigations. The advances made in those years can largely be ascribed to the work of Johan Hjort, who was the leader of the Directorate of Fisheries in Norway and an active participant in the affairs of ICES from the beginning. The research programmes carried out by Hjort and his collaborators were directed at all stages of fishes and their environment. Surveys covering wide ocean areas provided information on hydrography and plankton as well as on the distribution of eggs, larvae, and juvenile and adult fish, and sampling schemes of commercial catches produced knowledge on the size and age distribution of the catches and stocks. In ICES, Hjort argued strongly for age sampling of commercial catches on the largest possible scale so that stock age compositions instead of commercial size classes could be established for the purpose of predicting fishable biomass. He also indicated that such data could be used in a way similar to that applied for human populations. D’Arcy W. Thompson, who used commercial size classes in his analyses, opposed Hjort’s views for a long time, declaring that the method of age determination was not proven and that the number of rings inherring scales was subject to individual variations. This was probably the first serious rift in ICES since its inception and a reason why stock age structure studies did not become a routine tool in ICES before the 1930s. Hjort and his group in Bergen functioned as the leading fishery research institution in Europe until World War I and with his stock age composition concept. Hjort was at the point of achieving deeper insights into the complexities of exploited fish stocks. In the 1930s, British scientists developed theories on the effects of fishing on the stocks partly based on Hjort’s earlier findings and suggestions