Migrations of the sardine (sardina pilchardus) in relation to hydrographical conditions of the Adriatic sea

摘要: Abstract In the Adriatic Sea, sardine ( Sardina pilchardus Walb.) is economically most important pelagic fish species. It spawns from autumn until spring in areas which are strongly defined with regard to some hydrographical factors, such as temperature, salinity, current system, depth and others. These spawning grounds located optimal biological conditions, where equilibrium established between two types of sea water: “Mediterranean” one, “Alpic” one formed shallow northern part by dominated influence north Italian rivers. After spawning, search for food, migrate high productive regions summer intensively fished. Due topographical characters polarisation sea, subpopulations differ generally their directions, distances time migrations. But there indications that due environmental conditions limited mixing stocks inhabiting various Sea possible.