Fry ascent of marine migrant fishes at tidal channels of the Lesina coastal lagoon (Western Adriatic Sea)

Coastal lagoons are important environments, where fish recruitment sustains the exploitation of a number of euryaline fish species of commercial value, such as grey mullet Mugil cephalus and gilthead seabream Sparus aurata. The effective management of these fish stocks requires, besides their assessment, basic knowledge on recruitment dynamics and abundance, in order to manage a sustainable exploitation of this valuable resource. Aim of this study, inserted in MIDAN project, was to verify the migration schedule and abundance peaks of fry of the main species, in order to assess recruitment in the lagoon of Lesina for these fish species. Samplings were carried out fortnightly between September 2006 and May 2007 at the two tidal channels of the lagoon, by fyke-nets 2 mm mesh size. Environmental parameters such as weather conditions, direction and force of the wind, direction of the running water, water temperature, salinity, oxygen concentration and pH were also recorded. All captures were preserved in 4% formaldehyde solution, and then examined and identified to species level, and each individual was measured and weighted. The thin-lipped mullet Liza ramada has shown to be the most abundant species, followed by the golden mullet L. aurata and the grey mullet. Gilthead seabream has been found to be relatively scarce.