The biological flexibility of the pumpkinseed: a successful colonizer throughout Europe

Among the introduced species of fishes, the pumpkinseed Lepomis gibbosus (Linnaeus) is one of the most successful. During the last century, the pumpkinseed became established in most European countries, not merely by introductions but also by natural spreading into adjacent water bodies, and in many cases they attained high population densities in the receiving waters. Impacts on local ichthyofauna were first reported in Portugal and Spain, where pumpkinseed spread invasively (e.g. Zapata and Granado-Lorencio 1993, Godinho et al. 1997a, Godinho et al. 1998, Blanco et al. 2003). So, what makes this fish such a successful colonizer of new environments? It appears that it is the flexibility and plasticity of the pumpkinseed, so obvious in several aspects of its life history. This chapter reviews some of the most important literary sources on various aspects of the life history of the pumpkinseed, emphasising its flexibility. Where possible, the ecology of indigenous North American and introduced European populations is compared. The review is combined with our own original data that focus on the phenotypic plasticity of the species, thus addressing the high potential of pumpkinseed to colonize new environments.