32 



Gobbino, is opened at the same time through the sand- 

 banks of the Lido to provide direct communication 

 between the sea and certain of the southern valli and 

 carry thereto adequate supplies of sea-born fry. To 

 further facilitate the entry of fry and to ensure a uniform 

 distribution throughout the more remote valli as well as 

 those fed directly from the river sluices and sea-canals, 

 numerous gaps are cut in the dykes separating the valli 

 from one another and in the banks of the sea-canals 

 themselves. Every effort is directed to putting every 

 valle in free and untrammelled communication with the 

 rivers and the sea; to this end the sluices are opened, 

 the canal banks cut and dividing embankments breached; 

 all other duties yield to the vital necessity to obtain a 

 large stock of fry. 



During the period the lagoon is thrown open to the 

 free influence of tidal flow, a distinct current is produced 

 during the ebb, flowing outwards through the river 

 sluices and through the sea-channels. As we have seen 

 when discussingthe Arcachon system, this outward current 

 is the important factor in attracting the fry of eels, mullet 

 and atherine smelts — the three species particularly 

 desired at Comacchio — towards and into the lagoon as 

 at this stage in their life the fry obey an instinct which 

 leads them to swim against any sea-going current ; when 

 they once enter the lagoon they scatter and show no 

 immediate desire to undertake further journeyings. 



The abundance of fry entering the ponds being a 

 matter of the gravest anxiety to the authorities during 

 the months of ascent, employes of the commune supervise 

 the entrance of the shoals through the various sluices 

 and gaps. From time to time these men assure them- 

 selves of the quality of the harvest. The method is a 

 rough one, but answers sufficiently well ; it consists of 

 lowering bundles of brushwood into the entrance 

 channels ; these are periodically taken up and well 

 shaken or beaten, an action which causes all the eel fry 

 that have taken refuge in the interstices to fall out ; 

 according to the quantity thus obtained they gauge the 

 abundance or scarcity of the run of fry. 



The fish whose fry penetrate into the lagoon in this 

 manner consist in the main of eels {A. vulgaris), smelts 

 (Atherina Boyeri), gobies, mullet of several species ; a 



