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Indicators of krill flux at various spatial-temporal based on the data of multi-year research carried out in the Scotia Sea. Comments on krill fishery management

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Document Number:
WG-EMM-2019/58
Author(s):
S. Kasatkina and V. Shnar
Submitted By:
Dr Svetlana Kasatkina (Russian Federation)
Approved By:
Dr Svetlana Kasatkina (Russian Federation)
Abstract

The subject of research was geostrophic circulation of water masses, spatial distribution of krill density, intensity of water flows (m³/s) and krill biomass (g/m³) transported by water flow at various spatial-temporal scales in the Scotia Sea.  According the discussion at WG-EMM-2018 (paragraph 2.24-2.27), particular attention is paid to the special field studies across time to improve understanding of krill biomass dynamic.  It has been shown that the formation of transport of krill in the Scotia Sea requires both favorable dynamic conditions and krill influx from the Antarctic Pacific and the Weddell Sea.

The data obtained demonstrate that the dynamics of krill biomass in a given  area   is more dependent on the intensity and structure of krill transport over, and is not determined by the state of the local stock of krill and, especially, by the effect of the fishery on krill resources. The variability of fishery indices, also to a greater degree, is a reflection of the spatio-temporal variability of the processes  of krill  flux through the area of operation of the fleet.

Risk assessment of fishery management  requires adequate data on variability of biomass distribution and population structure of krill under the influence of its  drift at various spatial-temporal scales.