AN ASSESSMENT OF THE PACIFIC SALMON ONCORHYNCHUS ADULT ESCAPEMENT PARAMENERS FOR THE RIVER BASINS ON EAST AND SOUTHEAST KAMCHATKA
The current strategy of management of Pacific salmon resource in Kamchatka has in its basis the idea, that a certain optimal part of parental salmon (stock) should enter rivers within extensive area in commercial fishery districts as an escapement. Meantime, if there were commercial interests of several countries, the control of fishery should be based on certain volums of the catch and the escapement into each particular stream. In this article we make the escapement to fit the maximal sustainable catch, for the most important streams within the Petropavlovsk-Commander fisheries subzone. In view of precautionary approach to evaluation and in regard to uncertainties the escapement is given in the form of interval. Two methodical approuches are demonstrated. The method of data stratification for the maximal, minimal and intermediate levels of reproduction, relevant to changes in environmental conditions, was used for the river Kamchatka, where series of observations is long. In accordance with this, the escapement estimates are given in the form of interval (average and extremes). As for the other rivers, where the series of observations over the escapement is shorter or fragmental and the fishing normally operates in the coastal zone (where origin of the fish returned hardly can be identified), the data pools were analyzed in geographic clusters of several rivers. As a rule the cluster mentioned consisted of one big river and several minor rivers around. The parameters of the corporate "stock-recruitment" model for all rivers of South-East Kamchatka (except Kamchatka River) used for estimation of the escapement, can be splitted into the parameters of models for particular clusters depending on the average longterm annual parental stock and progeny (recruitment) in every cluster. The article is the first in a series addressed to the theme, where similar work is planned to carry out for the rivers of North-East and West Kamchatka.