The Gulf of Trieste is characterized by quite shallow waters (less 25 meters depth, Stravisi 2003) with
the most important tidal amplitude in the Mediterranean enhanced by basin geometry. The study area is
located on the northern part of Adriatic Sea, between Tagliamento and Isonzo river mouths where important
clam beds are exploited by local fleet armed with hydraulic dredges mainly on sandy bottom ranging from 2
till 6 meters depth.
Thanks to exhaustive geomorphological research done by Gordini et al [2003] it was possible to obtain
a detailed picture of the bottom features that can also be used to improve the knowledge of 3D (Fig.1)
distribution of the infaunal mollusc populations, to ameliorate the assessment and fishery management and
this achievement should be obtained using the GIS tools.
Here we examine the results of the surveys conducted in August and December 2009 on the Chamelea
gallina beds to support the fishermen organisation and Maritime Authority of the Monfalcone District. From
August to December the numbers/m2 of clams exhibits a general decrease even if the maximum is reached at
higher level due to the recruits become vulnerable to the sampling gear
