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.
Abstract:
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 key for the third quarter of the year is appended
Abstract:
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 were 2.5 years and 12.5 cm, respectively.
There is no abstract available for this document.
There is no abstract available for this document.
Abstract:
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.
There is no abstract available for this document.
Abstract:
Scales and otoliths were collected from 304 specimens of the Antarctic fish Notothenia gibberifrons. When interpreted separately, only 25% of scale and otolith readings agreed. When a scale and otolith from a single simultaneously, 75% of readings agreed. of otolith readings changed between specimen were interpreted 60% of scale readings and 30% separate and simultaneous interpretations. Estimates of age tend to be lower when made from scales. Predictions of yield per recruit utilising age data derived from scales are approximately 30% greater than predictions utilising age data derived from otoliths.
