WG-FSA-89

Some peculiarities of spatial and temporal variability of the glassfish distribution on the South Georgia Island shelf relative to environmental conditions have been revealed from summarizing and analysis of hydrographic and commercial fishery and biological data for 1986-1987.

Regularities of growth are established from the data of age determinations and analysis of yellowfin notothenia length-weight composition, mathematical description of length-weight dependence and parameters of Bertalanffy equation are given. Natural mortality coefficient, M, calculated by six various methods ranged from 0.63 to 1.06. With mean value of M, age and length at optimum exploitation Read More
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Radii of annual elements were calculated on the basis of studying C. gunnari length frequency distribution simultaneously with the measuring of otolith radii of fish taken in July-September. This was done using specimens from strictly’ defined age groups. These radii measurements suggest an adjustment to age determination of fish longer than 30 cm with an enlarged otolith centre. An age-length Read More
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Analysis and summarizing extensive materials on size-weight and size-age composition of South Georgia icefish for 1965-1987 enabled producing reliable weight-length dependencies for males and females by season and specify Bertalanffy growth equation parameters. Mean value of natural mortality rate was estimated at 0.55.