Tracking the invasion of Hemiramphus far and Saurida lessepsianus along the southern Mediterranean coasts: A Local Ecological Knowledge study

Local Ecological Knowledge of 92 professional fishers from Tunisia and Libya was used to investigate the occurrence and establishment of the exotic Hemiramphus far and Saurida lessepsianus along the southern Mediterranean coasts. According to fisherman’s knowledge, H. far and S. lessepsianus appeared in Libya in 1980 and 1989, respectively. In Tunisia these species were observed later on, in 2004 and 2007. Currently both H. far and S. lessepsianus are well distributed and established, along the entire surveyed area, from Tobruk (eastern Libya) to Tabarka (western Tunisia). A statistical analysis of the qualitative trends in abundance perceived by the respondents shows that both species have significantly increased in abundance in Tunisia. In Libya an increase in the abundance of H. far was also apparent during the first decade of the 21st century, but the current abundance of S. lessepsianus was found to be stable at the level of occasional captures. Given the lack of regular environmental monitoring programmes in the area, these findings provide information that could not have been obtained otherwise. Besides improving our understanding on the status and chronology of these invasions, this approach highlights the value of fisherman’s knowledge t