Assessment Of Wild Baltic Salmon Stocks: How To Combine Different Sources Of Information

No abstracts are to be cited without prior reference to the author.

Fisheries stock assessment can be hampered by the fact that data are often limited and patchy as is the case for wild Baltic salmon. Appropriate use of data from related populations i.e. Atlantic salmon populations and hatchery-reared salmon, can reduce the uncertainty regarding the status of the wild stock. This paper provides an overview of the methodology to estimate the abundance of wild Atlantic salmon in the Baltic Sea, using different data sets: mark-recapture data of wild and hatcheryreared salmon, stock-recruit data of other Atlantic salmon populations, data on catches and fishing effort of the different fisheries in the Baltic Sea and smolt abundance data. The output of the mark-recapture analysis and the hierarchical meta-analysis of stock-recruit data of Atlantic salmon stocks provide information on the fishing mortality rates of wild salmon in the different fisheries and about the likely form and parameter values of the stock-recruit function of Atlantic salmon. These parameter estimates are used as informative prior knowledge in an age-structured life-history model, fitted to catch and smolt abundance index data, to estimate the status of wild salmon in the Baltic Sea. The results of the methodology are presented in appropriate formats for regional and local managers.