Life-history traits of the invasive and biggest European freshwater fish, the wels catfish (Silurus glanis) show high potential for colonisation in Southern Europe

Abstract

Context The invasive wels catfish is spreading to many European waterbodies and is the subject of controversy concerning its environmental impact. Aims The objective was to investigate its life-history traits (growth and reproduction) for the first time in southern France. Methods A culling action was used to assess the key life-history traits, using sections of pectoral spines for age and growth estimations, and gonad macroscopic examination for the reproduction parameters. Key results The biggest individual was a 227-cm male. The age was accurately estimated from clear translucent marks on spines, with a maximum of 13 years for both sexes. The growth appeared to be extremely rapid and was the highest at old ages recorded from both the native and the invasive distribution range. The length and age at first sexual maturity, 70.1 cm for 4–5-year-old females, and 54.1 cm for 2–3-year-old males, were the lowest recorded in Europe, indicating an early maturity. Conclusions The life-history parameters (rapid growth, early maturation, high fecundity) showed a very high potential for adaptation and colonisation. Implications The cost and management required to regulate the species appear not easily feasible, particularly when combined with its high growth rate.