Valutazione del ruolo ecologico di alcune specie ittiche Lessepsiane nell'ecosistema costiero libanese

Responsabili di progetto

Fabio Fiorentino1, Stefano Lelli

Accordo

LIBANO - CNRS-L- not in force - National Council for Scientific Research of Lebanon

Bando

CNR/CNRS_L 2015-2016

Dipartimento

Scienze del sistema terra e tecnologie per l'ambiente

Area tematica

Scienze del sistema Terra e tecnologie per l'ambiente

Stato del progetto

Nuovo

Proposta di ricerca

The 220 km Lebanese shoreline is host to 4 commercial ports and tens fishing harbours, dozens of oil terminals, power plants and fuel tank farms, and a multitude of industries. The coast is under the influence of competing interests which have caused a marked deterioration in the coastal water quality, ecological sites and natural resources. The rapid demographic change and associated urbanization has greatly increased the demand on coastal resources. Protection measures, either for species or ecosystems, are still rare. Lebanese fishing communities have always been neglected likewise it was the scientific research applied to this sector. Fishing operations are mostly carried out at a depth up to 50 m increasing the competition on coastal resources. Illegal fishing behaviours and bad practices, the human pressure on the coastline, along with the low public investment in the sector during the past decades have narrowed the economic value of the sector and therefore negatively affected fishers' lives. Despite its chaotic management, the Lebanese fishing sector represents a unique case in the Mediterranean, being the only one solely composed by small-scale artisanal vessels. Lebanon is moving its first steps in the fulfilment of international requirements in terms of data collection on its halieutic resources through stocks, catch and effort assessments. International organizations and donors have granted funds and capacity building to develop adequate research programmes to support the capability of the Lebanese Government to define new measures towards an appropriate and sustainable management of fishing resources. Capacities of the CNRS-National Centre for Marine Sciences (NCMS) have been built in the last years to run independently fishing surveys to collect and analyse biological data on fish and shellfish species inhabiting the continental shelf and upper slope (fishing grounds exploited by Lebanese fishermen). This baseline information is necessary to set appropriate policies that take into consideration the status of the stocks of commercial species, major assemblages and ecological interactions. The projects CIHEAM-Pesca Libano and CANA-CNRS coordinated a series of actions through which the NCMS was able to run the first fishing surveys to assess abundance and distribution of halieutic resources inhabiting the Lebanese continental shelf and upper slope in 2012 and 2013. CNRS is giving due durability to those actions by funding, through its CNRS Research Programme, a two-year project that intends to provide more detailed information on seasonal patterns in the composition and assemblages of the resources by means of seasonal fishery-independent surveys in the North of Lebanon. These new experimental surveys offer the opportunity to collect and analyse additional data to those included in the survey protocol, to bridge important gaps in the knowledge of key Lessepsian species' ecology in Lebanese waters. Although the importance of Lessepsian migrants (i.e. Red Sea species entering the Mediterranean via the Suez Canal) is rapidly increasing in the Levantine basin, the knowledge on the role that these species play in the ecosystem, as well as their ecological traits (i.e spawning periods and sizes, growth, feeding behaviour), is still scattered or lacking. The aim of the present project is to develop a protocol for data collection, which combines experimental surveys and collection of samples from commercial catches to investigate the ecology of three important Lessepsian migrants, namely Sargocentron rubrum, Nemipturus randalli, Scomberomorus commerson, considered important for their abundance and/or commercial value. A joint team of scientists from NCMS and CNR-Institute for Coastal Marine Environment (IAMC) will develop laboratory protocols to analyse the ecological traits of the selected species, including growth through advanced techniques of otoliths reading, spawning and trophic behaviour also considering the possibility to integrate direct diet analyses with stable isotopes techniques. Otoliths will be collected and stored dry to be analysed in the fish growth laboratory of IAMC at Mazara del Vallo, exploring some advanced techniques that include sectioning, back calculation of rings using image analysis tools. Gonads maturity stages will be defined at the CNRS-laboratories and analysed on a monthly basis to identify spawning periods and size at maturity. Information on growth and maturity is relevant to understand the growth potential of the populations and to gather information to set management rules (i.e. fishing seasons, minimum landing sizes). Finally, stomach contents analysis will be carried out to elucidate the trophic role and trophic interactions of the species in the ecosystem. For one of them, diet analysis will be combined with the analysis of stable isotopes in the tissues taking advantage from the laboratory facilities of IAMC (Capo Granitola). Carbon and nitrogen contained in fish tissue originate from the diet of the animal. The ratio of stable isotopes (13C/12C, 15N/14N) of the diet is transferred to the tissue of the fish. Therefore the analysis of stable isotopes in fish tissues provides information on the isotopic composition of the fish's diet. Properly applied, stable isotope techniques produce estimates of trophic position that simultaneously capture complex trophic interactions, including trophic omnivory, and track energy or mass flow through the reticulate pathways of ecological communities. Thus, they can provide a powerful tool for testing food-chain theory, for evaluating the effects of invasion on food web structure, and for estimating the trophic position of and trophic differentiation between species. IAMC scientists will offer therefore on the job training to NCMS' researchers on different aspects related the collection, the advanced analysis in laboratory of fish data, transferring to them their consolidated experience in this field.

Obiettivi della ricerca

Objective of the project is to investigate the ecological traits of some key fish Lessepsian species (i.e. Sargocentron rubrum, Nemipturus randalli, Scomberomorus commerson) in Lebanese coastal waters. Through advanced techniques of data collection and analysis in laboratory, the CNRS-IAMC research team intends to gather new knowledge on the selected species on aspects related to growth, maturity and trophic role, also through the analysis of the isotopic composition. The joint analyses will offer the opportunity to the NCMS team to learn new techniques taking advantage from the laboratory facilities at the IAMC and the consolidate experience of the IAMC team in this research field. In this regard, the project intends to contribute to strengthen the capabilities of CNRS in providing sound scientific advices on the status of fisheries resources, towards the development of policies that could bring sustainable economic and social benefits to Lebanese fisheries sector. The project also aims to underpin the CANA-CNRS project's component devoted to fisheries and to give a first substantial follow-up to the Twinning Programme between the R/V URANIA and the R/V CANA-CNRS signed by CNR and CNRS on March 27, 2014.

Ultimo aggiornamento: 24/04/2024