Escapement of eel (Anguilla anguilla) in coastal areas in Sweden over a 50-year period

Abstract

Abstract Andersson, J., Florin, A.-B., and Petersson, E. 2012. Escapement of eel (Anguilla anguilla) in coastal areas in Sweden over a 50-year period – ICES Journal of Marine Science, 69: 991–999. The escapement of eel from coastal areas in Sweden during the last 50 years was assessed using data from voluntary fishery journals and fishery-independent coastal fish monitoring programmes. It was evident that the level of escapement, determined as catch per unit of effort in numbers, from the Baltic Sea decreased over time, with the most rapid decline occurring in the 1960s and early 1970s, but also in recent years. There were, however, differences in the temporal variability in escapement between areas. Escapement from the northernmost studied site did not change significantly during the last 50 years, while there was a rapid decline in the southern areas. Escapement remained relatively stable between the late 1970s and 2000 however, and escapement at the Swedish west coast, inferred from yellow eel catch per unit of effort, generally increased during the same time. The loss in numbers has to some extent been compensated by an increase in mean weight of silver eel. Possible explanations for the retained level of escapement during the last decades despite the continued reduction in recruitment are discussed. Favourable environmental conditions in combination with a lower fishing effort are suggested as the most probable reasons why the escapement decline has not been more dramatic, but stocking and density-dependent effects cannot be ruled out.