Optimization Of A Structure Of The Spawning Stock Of The Northeast Arctic Cod Is A Key To Its Rational Exploitation

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A model of recruitment of a commercial cod stock has been worked out for two sufficiently long historical periods of fishery: 1952-1967 and a period after 1978. The basis of the model is an idea on the non-stationary process of recruitment as an random function along the entire discussed times series (1952-2000) and on the elementary components of a spawning population, as well as an idea on existence in it of structures with different qualitative composition of spawners and their different contribution into the recruitment, as well as a Ricker’s model “stock-recruitment”. The model takes into account the water temperature in the period of a change of a biotope, i.e. the transition of 0-group to the bottom mode of life. In each of two historical periods, three additive abundance components of the mature part of the population were revealed with different contribution into the recruitment, which are used as indices of a reproduction potential. The contribution of each component, as well as of temperature factor into the recruitment of a commercial stock was estimated. Estimations of components at which maximal contributions are reached were called optimal ones. It was concluded that the rational exploitation of cod stock suggests such planning of a catch composition, which would ensure an optimal structure of the mature part of the population.