Untitled - CNR

Marine research at CNRd1CannelleChannelAcquarotta ChannelAcq.23aLesinac4Adriatic SeaLesina Lagoon5bDrainagePumping Stationof PillaElce Channel67Pilla ChannelZannella RiverSchiapparo ChannelSch.9c8d d dLauro RiverSannicandroGarganicob DrainagePumpingStationof LauroaaPoggio Imperiale2,5 kmFigure 1: Location of sampling stations in Lesina Lagoon. Population centres, a;drainage pumping stations, b; urban wastewater treatment plants, c; fish farms, d.adult fish to enter.Freshwater inputs are supplied mainly bytwo year-round tributaries, Lauro and Zannella,whose waters enter the lagoon at theeastern end. There are also numerous otherintermittent channels and two drainagepumping stations, Lauro and Pilla, also locatedin the eastern part of the lagoon,which pump waters drained from the surroundingcountryside. Lesina Lagoon hasa characteristic E-W salinity gradient dueto the concentration of freshwater inputs inthe eastern area of the lagoon, which becomesmore pronounced during summer.Salinity also varies from one year to anotherdepending on the volume of waterexchange with the sea, the amount of precipitationand the pumping of surface watersfor the irrigation of nearby agriculturalland. Since the construction of the lavorieriin 1999, salinity has decreased continuouslyand currently varies from 6 to 38[22, 23]. The gradient has also become lessintense.Fishers’ cooperatives run the fishing areasunder concessions which are granted at thebeginning of the season. The artisanal fishingthey practice in the lagoon is basedmainly on the use of fixed nets, known locallyas paranze. These are nylon seineswith a 6-mm mesh stretched across the lagoonfrom one side to the other, whichchannel the fish into fyke-nets (also with a6-mm mesh) positioned at regular intervalsalong them. These are installed in Septemberand kept in use until February of thefollowing year.2.2 Sampling and data analysisBetween September 2006 and May 2007,every fifteen days, a fyke-net with a 2-mmmesh and wings about 130 cm long wasplaced near the lagoon end of each channelfor 24 hours with the mouth facing towardsthe sea (Figure 1). The catch wasremoved about every six hours to preventthe animals from dying. Young-of-the-year2101