Eastern Baltic cod (Gadus morhua callarias) stock dynamics: Extending the analytical assessment back to the mid-1940s

Abstract

The status of the eastern Baltic cod (Gadus morhua callarias) stock has been assessed annually by ICES since 1966. To understand better the causes of stock fluctuations and to evaluate human impact on the stock relative to natural variability, longer timeseries than currently available are needed. To achieve this, data back to the mid-1940s were compiled to extend the analytical assessment. Estimates are provided of stock development and its exploitation for a 20-year period before the start of the current assessment. The quality of the data and the credibility of the historical estimates are discussed. Considerable fluctuations in cod biomass and recruitment in the pre-assessment years were identified. Stock size was estimated to be relatively low after the Second World War, then increased during the first half of the 1950s, but did not reach the high levels of abundance subsequently observed in the early 1980s, and then declined towards the mid-1960s. Fishing mortality was low after the Second World War but increased rapidly in the second half of the 1950s, reaching the high levels observed since the 1980s. © 2007 International Council for the Exploration of the Sea.