Dynamics of numbers of commercial fish in early ontogenesis in different areas of the Central-Eastern Atlantic

摘要

Changes in the quantitative composition of mass fish species at early stages of ontogenesis in different areas of the Central-Eastern Atlantic (CEA) in warm and cold seasons in 1994-2008 were analyzed in the paper. The most widespread representatives of ichthyocenosis of CEA were: European pilchard (Sardina pilchardus), common scad (Trachurus trachurus), round sardinella (Sardinella aurita), and West-African scad (Trachrus trecae). The data obtained indicate that, within the economic zone of Morocco, fluctuations of numbers at early stages of development in European pilchard and common scad are close over the entire water area under consideration (36A degrees-21A degrees N). The regularities of fluctuations of the numbers of ichthyoplankton are similar to the interannual changes in the biomass of fish in the area of Morocco. In the area of Mauritania (21A degrees-16A degrees N), fluctuations of numbers of the early stages of development of commercial fish cannot be unambiguously correlated with changes in the biomass of adult fish. It is known that, in the economic zone of Mauritania, there are Senegal-Mauritanian populations of round sardinella and West-African scad that inhabit waters of different states and are not completely assessed by our surveys. Therefore, no obvious relation was observed between the considered data.