100 years ago, Johan Hjort wrote his seminal fisheries science work, Fluctuations in the great fisheries of northern Europe, which featured new conceptual ideas about the formation of strong year classes based on age determination techniques from fish scales. Hjort's research still receives 40–50 citations every year, making it an exceptionally influential study that continues to drive fisheries science to this day.
To commemorate the centenary of Hjort's work, the ICES Journal of Marine Science (IJMS) has published a special issue of thirty-two articles that demonstrate the deep influence he has had, and continues to have, on fisheries and marine science. The articles take up questions addressed by Hjort, whether through the use of new innovations in sampling and analysis, the application of mathematical models, adding climate change as a context, or with a slightly new spin.
The Norwegian scientist, one of the giants of fisheries biology, already considered during his time the managerial and societal implications of fisheries research. In addition to his research, he was an advocate for international cooperation and one of the founding fathers of the International Council for the Exploration of the Sea (ICES). Hjort served as ICES President from 1939—48 and helped launch joint research activities, for example those in the North Sea, as well as extensive cruise programmes.
The works of Johan Hjort will continue to interest, influence, and challenge fisheries scientists globally. As he himself predicted: "…the object can never be fully attained; new questions will constantly arise, as the knowledge obtained creates the demand for new, and it will always be possible to increase and intensify our comprehension of the vital conditions affecting the organisms in question."
The entire IJMS issue is now freely available for download on the IJMS website.