A brief comprehensive account on Lessepsian migration is given in the present study. Earlier publications reported that the dusky spinefoot fish Siganus luridus (Ruppell, 1829) and the marbled spinefoot S. rivulatus (Forsskal,1775) were recorded in Libya Mediterranean coastal waters for the first time in 1968 and 1970 in order. The present study however, shows that they were in Libya since the 1950ties: in Tobrok in 1950, in Darna in 1954 and in Benghazi in 1960. These findings were based on questionnaires filled by middle age and elderly fishers (located in Tobrok, Ein Ghazala, At Timimi, Ras Ettin, Darna, Khalij Bumba, Susah, Benghazi fishing sites on eastern Libya), on reports and documents of “Darna Fishers Trade Union”, “Tobrok Fishers Trade Union” and “Office of Marine Resources in Darna” and on consultations with members of these institutions. Estimates of monthly catch from the two Siganids per fisher per fishing site shortly after they established themselves in the eastern coast ranged between 2 to 60 kg (average = 17.25 kg) with S. luridus been more abundant than S. rivulatus. Both fishes are residents of shallow coastal water, 1 – 8 meters deep (average = 4.25 meters). Average total length of the initial population the two Siganids was 23.44 cm. Questionnairing fishers, in particularly elderly ones, is a powerful new technique for establishing more accurate records of first entry than that given by scientist. However, this technique is limited by the scarcity in elderly fishermen who are inventory of information of the old times but are unfortunately eliminated through time. Yet the approach may not be too late for many Lessepsian fishes and scientists are encouraged to use it.
Keywords: Lessepsian migrants, Mediterranean Sea, Siganus luridus, Siganus rivulatus, dusky spinefoot fish, eastern Libya, marbled spinefoot
