Volume 5/issue2/volume5
Issue 2
Fisheries
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Available Online: http://www.ejpau.media.pl/volume5/issue2/volume5/issue2/fisheries/abs-01.html
ENVIRONMENTAL CONDITIONS OF COMMON STURGEON (ACIPENSER STURIO L.) SPAWNING IN RIVER RIONI (GEORGIA)*
Ryszard Kolman, Zurab Zarkua
ABSTRACT
Environmental conditions in River Rioni (Georgia) were studied in two seasons, during purported spawning migrations of the common sturgeon. Water temperature and flow velocity were measured in the vicinity of Poti (downstream section of the river) and in the potential spawning areas. At comparable times, water temperature in the spawning grounds was by a few degrees lower than that downstream, the flow velocity being higher and ranging within 1.5 - 2.1 m s-1. As shown by the observations, the area suitable for the sturgeon spawning had shrunk, possibly as a result of river damming. In the areas suitable for the common sturgeon spawning, the river bed was covered by coarse gravel and flattened stones, those measuring up to 30 mm in diameter being most abundant.
Key words: endangered fish species, common sturgeon, Acipenser sturio, Black Sea, natural spawning, environmental conditions..