Abstract
In the changing environmental conditions of the Caspian Sea, and specifically following the accidental introduction of the comb jelly Mnemiopsis leidyi from the Azov–Black Sea basin in the late 1990s, ecosystem functioning has been disturbed, particularly in the pelagic zone. The main commercial species of kilka in the Caspian, anchovy kilka (Clupeonella engrauliformis), suffered greatly from the introduction. The catch of kilka by Russia, Azerbaijan, and Iran dropped from 182 700 t in 2000 to 74 700 t in 2001, although the total allowable catch remained at 300 000 t. Between 2000 and 2004, the catch by Azerbaijan alone dropped from 18 500 t to 5 100 t. Recruitment of anchovy kilka failed in early 2001, resulting in an increase in the average age of the stock, and a big decline in abundance. During kilka surveys conducted in summer 2003 and summer 2004 along the Azerbaijan coast of the central Caspian, the average cone-net catch varied from 19.8 kg to 30.5 kg at depths of 51–90 m, and along the Azerbaijan coast of the southern Caspian from 6.1 to 33.7 kg at depths of 53–81 m. Information is provided on the biology and apparent environmental preferences of the three kilka species of the Caspian, specifically their age composition, growth rate, and mean weight, off the coast of Azerbaijan.
Influence of vertical distribution of phytoplankton on remote sensing signal of Case II waters: southern Caspian Sea case study
