Abstract
Abstract The number of marine alien species in Libyan waters has increased from 63 (known until the end of 2013) to 73 in the present study. This work deals with the present status, distribution and characteristics of marine alien species and their impacts along the coast of Libya, almost 2000 km long. The highest percentage was fishes (32.88%), followed by macrophytes (21.92%), molluscs (16.44%), crustaceans (13.70%), and parasites (9.59%). Some of these species have successfully adapted themselves to various topographies and habitats in the Libyan coasts, which resulted in the change in biodiversity in the area. Some fish were accompanied by parasites and others have become hosts for native parasites; seven alien parasite species (Nybelinia africana, Neoallolepidapedon hawaiins, Allolepidapedon petimba, Glyphidohaptor plectocirra, Tetrancistrum polymorphum, Apounurs sigani and Hatschekia siganicola) were recorded in three lessepsian fish species. Moreover, the toxic effect of poisonous fish (Lagocephalus sceleratus) was investigated as it caused fatalities and severe intoxication for some fishermen. Its population has dramatically increased, with high numbers of juveniles and adults reported in some bays especially in the eastern part of Libya. Alien Siganus spp. have competed with the native herbivore fish Sarpa salpa. Furthermore, some alien fishes have become commercially valuable in Libya. This paper highlights the biological invasion in the Libyan coasts in an attempt to fill the gap of knowledge on the alien species in the southeastern Mediterranean coast. Keywords: Bioinvasion, migrant species, South Mediterranean, Libya