Les particularites des facteurs hydrologiques le long du littoral roumain de la Mer Noir et leur influence sur la repartition et la migration des poissons industriels

Abstract

The author describes the peculiarities shown by the major hydrologic factors prevailing on the Romanian coast of the Black Sea, and their effects on the distribution and migration of industrial fishes, based on the investigations made during the period 1952-19CG at the former Station for Sea Research "Gr. Antipa" in Constanta. The results recorded outline the fact that the hydrological factors prevailing on the Romanian coast are characterized by the existence of wide variations both with time and in the space, especially in the superficial layer of the water. This situation is primarily determined by the specific character of climate conditions as well as by the huge amount of fluvial soft waters brought from the North-West side of the basin. When compared with other sections of the Black Sea, the Romanian coast discloses some distinct peculiarities corresponding to as many benefits and drawbacks from a biological standpoint. The assets are: the wide coverage of the continental plateau and the considerable contribution in biogenetic substances brought by fluvial waters, which result in a high trophicity for the area; the drawbacks are due to the fact that along the whole year there is not one single period to meet the conditions required far high concentrations of industrial species of fishes to build up within restricted certain given spaces, which is in the last analysis the determinant factor for an efficient fishing activity. The correlations between the hydrologic factors investigated and the biologic phenomena recorded explain, for a great part, the specific character of the fishing activity along the Romanian coast of the Black Sea and premises to make a choice among the steps to be taken to ensure a rational and efficient fishing activity.