Macroscale Zones Of High Biological Productivity In The Southpacific Ocean As A Probable Explanation For The Existenceof Relatively Isolated Jack Mackerel (Trachurus Murphy) Stock Units

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Based on analysis of the data on water dynamics (from the international projects WOCE and Argo) and satellite altimetric measurements of the ocean surface level and chlorophyll concentration in the surface layer, macroscale zones of high biological productivity have been identified. These zones are related to closed circulations of intermediate water of Antarctic origin. These waters contain 8-10 times more nutrients than the intermediate water of the northern origin. This means that when upwelled into the photic layer under the impact of mesoscale eddies they form quasistationary zones with high biological productivity located in the western, central, and eastern parts of the South Pacific Ocean. Comparison of the location of these zones with jack mackerel distribution at all life cycle stages (biostatistical and fishery data from catches of research and fishing vessels) allows us to advance a hypothesis on the availability of three relatively isolated stock units of jack mackerel, each of which requires a specific strategy of fishery management