TRACKING CHANGES IN FISH ABUNDANCE ACROSS THE COAST OF LEBANON: A LOCAL ECOLOGICAL KNOWLEDGE STUDY Safia Alajlan *, Ernesto Azzurro and Michel Bariche American University of Beirut - sha55@aub.edu.lb ISPRA,Italy Abstract The current work aims at detecting changes encountered in fishery landings along the Lebanese coast using an LEK approach. Preliminary results mainly indicate a decrease in the abundance of native as well as invasive species having commercial importance. Furthermore, we found an increase in a number of invasive species that are considered as pests to fishermen, while others were found in high abundance despite fishing pressure. Keywords: Alien species, Levantine Basin, Global change, Fisheries 1 2 1 1 2 Introduction The eastern part of the Mediterranean Sea has been severely impacted by anthropogenic activities, such as coastal degradation, overfishing, species invasions and seawater warming (1). Local Ecological Knowledge (LEK) can be defined as the information accumulated over time by a group of local people through observation and interaction with the natural environment. LEK is emerging as a powerful, low cost, information source on natural ecosystems, complementing “traditional” scientific research (2). Gathering information from the local fishermen can improve our understanding of the temporal changes occurring within the marine ecosystem, as recently showed for Mediterranean fish (3). Here we apply this methodology with the aim to reconstruct recent changes in fishery landings along the Lebanese coast. Materials and Methods Regular visits to fishing ports spread along the entire coast of Lebanon are being undertaken to interview fishermen, which were selected based on ᴠᴒᴛᴖᴜᴟᴖᴡᴦ ӿᶒ ᴦᴒᴎᴟᴠ ᴜᴓ ᴒᴥᴝᴒᴟᴖᴒᴛᴐᴒԐ ⱨ ᴡᴜᴡᴎᴙ ᴜᴓ  ᴓᴖᴠᴕᴒᴟᴚᴒᴛ ᴓᴟᴜᴚ ᴣᴎᴟᴖᴜᴢᴠ parts of the country have been interviewed so far following a survey questionnaire. This questionnaire has been adopted from the CIESM Tropical Signals Program ( http://www.ciesm.org/marine/programs ), and slightly modified to accommodate the specific requirements of the Eastern Mediterranean region. Results and Discussion Preliminary results showed that several native fish species, such as Mycteroperca rubra, have decreased dramatically in size and abundance as they have been overexploited by the local fishery. Exotic species showed different patterns of abundance in the landings: The populations of some invasive species have considerably increased and this correlated with their date of invasion, especially for those of non-commercial importance (e.g. Lagocephalus sceleratus). However, other species (e.g. Upeneus moluccensis) have declined significantly, after having an initial stage of population expansion. The latter have been highly targeted because of their market value. In contrast, other species have displayed a high abundance despite significant fishing pressure (e.g. Siganus rivulatus). Surveying LEK from the coastal waters of Lebanon has shown encouraging preliminary results. This simple and innovative approach has open up new opportunities to detect temporal changes in fish diversity and abundance in the Levant. Acknowledgements This study has been conducted within the framework of the CIESM tropical signals program. We kindly acknowledge all the Lebanese fishermen who participated in the survey. References 1 - Coll M., Piroddi C.,Steenbeek J., Kaschner K., Ben Rais Lasram F., et al. 2010. The Biodiversity of the Mediterranean Sea: Estimates, Patterns, and Threats. PLoS ONE 5(8): e11842. doi:10.1371/journal.pone.0011842 2 - Anadón JD., Giménez A., Ballestar, R and Perez I., 2009. Evaluation of Local Ecological Knowledge as a method for collecting extensive animal abundance data. Conservation Biology 23: 617-625. 3 - Azzurro E., Moschella P. and Maynou F., 2011. Tracking Signals of Change in Mediterranean Fish Diversity Based on Local Ecological Knowledge. PLoS ONE 6(9): e24885. doi:10.1371/journal.pone.0024885