Artificial upward trends in Greek marine landings: A case of presentist bias in European fisheries

Abstract

According to the official landings as reported by the international databases for Greece, the declining trend of the Greek marine fisheries landings that had been continuous since the mid 1990s has been reversed during the last three years, with the total marine fisheries landings showing elevated values after 2016. We claim that this upward trend is an artifact that is attributed to the combined reporting of the landings of additional fleets since 2016 that had been separately reported before and resulted in 20–30% inflation of the landings. In 2016, the Greek statistical authorities included the landings of an extra fleet of 10,000 small-scale coastal vessels with engine horsepower lower than 20 HP together with the remaining coastal vessels, purse-seiners and trawlers whose landings formed the official reported Greek marine fisheries landings from 1970 to 2015. We acknowledge that this act of partial catch reconstruction improved the resolution of the landings and the officially reported values are now more realistic. However, the artificial, albeit inadvertent, inflation of the official Greek marine fisheries landings as they appear in international databases is a clear case of ‘presentist bias’ and may distort stock assessments and ecosystem modeling. As the currently misleading data stand, they are cause for substantial misinterpretation and analytical errors that can influence fisheries policy and have serious implications for fisheries management. We suggest that researchers should refrain from using the combined time-series and that a correction should be applied to the original time-series (1970–2015) to account for the entire coastal fleet.