Climbing back up what slippery slope? Dynamics of the European eel stock and its management in historical perspective

Abstract

Abstract Few fish stocks are as influenced by (intentional and inadvertent) human impacts as the European eel, all across the continent. The dynamics of this stock, however, are poorly understood—neither the causes of the historically low abundance, nor minimal protection levels, are beyond discussion. Rather than analysing contemporary processes, this article turns back in time—two centuries or more—unravelling historical abundances and distribution patterns; reviewing historical actions and objectives; and discussing technical developments and scientific advice—picturing the slippery slope the eel stock has come down from. The first claim, that the continental stock was in decline, dates from the early 1800s; stock-enhancement actions were initiated shortly after. Diffuse objectives, technical innovations, eternal optimism, and—above all—no quantification impede the exact evaluation of historical reports. After 1950, when quantification improved, a slow but consistent decline was observed, but it is only two decades after the crash in glass eel recruitment (in 1980), that protection plans addressed the bad status of the stock. A slippery slope, full of pitfalls—yet, we now observe several years of increasing recruitment.