Introduction of exotic fish into a Mediterranean lake over a 90-year period
García-Berthou, Emili; Moreno-Amich, Ramon
Archiv für Hydrobiologie Volume 149 Number 2 (2000), p. 271 - 284
published: Sep 29, 2000
ArtNo. ESP141014902010, Price: 29.00 €
The impact of exotic species is a neglected, worldwide ecological problem, particularly for freshwater fish. Examples of historical changes in southern Europe due to fish introduction are rare. Lake Banyoles, the second largest lake of the Iberian Peninsula, has suffered a long history of fish introductions. We reviewed the historical changes in the fish assemblage and assessed its current state in a field study. Before 1910, only five or six native species were present. During this century up to 12 exotic species were introduced, leading to the apparent loss of two native species (threespined stickleback Gasterosteus aculeatus and, possibly introduced several centuries ago, tench Tinca tinca) and the decline of three others (eel Anguilla anguilla, chub Leuciscus cephalus, and barbel Barbus meridionalis). The current fish assemblage is dominated by exotic species, particularly the largemouth bass (Micropterus salmoides) and the pumpkinseed sunfish (Lepomis gibbosus) in the littoral zone and roach (Rutilus rutilus) in the pelagic zone. The only native species still common nowadays is the freshwater blenny (Salaria (= Blennius)fluviatilis).