Incidence of lessepsian migrants on landings of the artisanal fishery of south Lebanon

In the last decade, a growing amount of evidence incorporated by several authors as signals of global changes, defined a trend of expansion of thermophilic species in the Mediterranean. This phenomenon is markedly shown by the spread of some non-indigenous fish beyond their natural limits and by their success in the new colonized areas. The incidence of those non-indigenous fish in the catch composition of the artisanal fishery of Tyre (south Lebanon) was investigated for the first time using both official data and daily landing site surveys. The investigatory fleet consisted of 250 small vessels (4–10 m length) with old and not very powerful engines, and about 400–550 fishermen at the end of 2005. Most of the fleet used different types of bottom standing gear, such as trammel nets, set gill-nets and bottom longlines, whereas purse seines and other fishing gear (floating longlines and traps) were used less frequently. Landings comprised a great number of species, many of which were lessepsian migrants. We recorded a total of 25 lessepsian species, representing 17 families and comprising 37% of the total landing by weight. Some of these non-indigenous species have become important components of local fisheries in the area.