Natural mortality rates of the Antarctic krill Euphausia superba Dana in the Indian sector of the Southern Ocean

Data on the size and age composition of Euphausia superba were collected in the Cooperation and Cosmonaut Seas from 1985 to 1990.
The coefficients of instantaneous natural mortality of E.superba in the Indian sector of the Southern Ocean were calculated according to Alverson-Carney’s (1975), Richter-Efanov’s (1977) and Beverton-Holt’s (1958) methods. Values varyed from 0.72 to 0.87, from 0.41 to 0.59 and from 0.94 to 2.30, respectively.
The estimation of the annual extinction rate of E. superba was obtained using the method of Zikov,Slepokurov (1982) and results were best fitted by a parabolic equation. The coefficients of natural mortality of E. superba derived with this method range from 0.49, during the maturation period, to 1.17 and 3.22 during the first and last years of life, respectively.