OPTYMALIZACJA STATYSTYCZNA JAKO NARZĘDZIE ZARZĄDZANIA GOSPODARKĄ RYBACKĄ.

The econometric model can be a precise instrument for the analysis of an impact of the natural environment deterioration on management effects. This work presents the results of research in the field of an impact of lake water pollution on the effects of the fishery management. The economic-ecological models have been constructed, explaining changes of economic effects of the lake fishery in the conditions of an increasing water pollution and optimal levels of content of different substances in lake water, from the point of view of the fishery management, presenting the catch of Coregonus albula as an example. When in the model made up of G of stochastic equations, yit is a scale of this type of catches and xtj is a level of content of j-this substance in water (j=1,..., k), a structural parameter aij can indicate three possible situations: 1) if aij =0, then the concentration levels of j-this substance observed in a lake are neutral for a scale of i-this type of catches, i.e. a level of lake pollution significant for the considered i-this effect does not exist; 2) if aij>0, then levels of a given j-this substance in the lake water are below the zone of neutrality, what makes them even stimulators of development of a given fish population; 3) when aij<0, it means that a lake water pollution is above the level of neutrality which has a negative impact on the ithis economical effect considered here. An optimisation of a vector of the lake water quality features is possible from the economic point of view. Quadratic equation yi =a ijo + aij1xj + aij2 + xj 2 (1) is characterized by a maximum, if aij2<0. A graph of parabola (1) allows for the analysis of dependencies of positive catch scales of i-this fish species on nonnegative concentrations of j-this substance contained in the water. The optimisation of the fishery management can be carried out for any number (n>3) of substances and characteristics of the lake water. As a result we can identify three types of dependencies of catch scales of i-this fish species on a content of j-this substance in the lake water. An optimal concentration of j-this substance (xj (i) opt) for i-this fish species is included in the range of the acceptable concentrations {xj (i)opt Î D}, where Dij={xj (i) mn,..., x(i) jmk}. Each content of j-this type of water component not included in the range of the acceptable concentrations (xj (i) ÎDij} – from the point of view of catches of i-this fish species causes the extinction of this species. The empirical verification of hypotheses was performed on the basis of catches of Coregonus albula in Lake Charzykowskie (protection zone of the National Park ”Tucholskie Forests”). The proposed optimisation procedure could be a significant tool for programming an efficiency of the fishery management in the conditions of maintaining the ecological equilibrium. [ABSTRACT FROM AUTHOR]