Length‐weight relationships of Baikal omul Coregonus migratorius during the feeding season in the Selenga area, Russia

Aim. To refine the LWR coefficients for the Baikal omul Coregonus migratorius (Georgi, 1775).Material and Methods. The data set (number of fish, standard length (SL), weight (W), sex and morpho‐ecological group (MEG) for the study of the LWR coefficients were taken from the Baikal Omul database. The analysis includes data from 3,091 specimens of Baikal omul, collected in May to June 2003, 2006 and 2007 and in September 2004 in the area adjacent to the delta of the Selenga River. The construction of regression models of LWR was carried out for all data without taking into account gender and MEG. In addition, regression models of LWR data were obtained, grouped by gender and belonging to a certain MEG.Results. Dependencies with close values of the coefficients of the power function are obtained. There were no significant differences between fish of different sexes and MEG, the coefficients differing at the level of statistical error. It is shown that the LWR in fish during feeding periods of different years is quite stable.Conclusion. We offer the equation W=10,9(SLdm)3.02 that has acceptable coefficients for C. migratorius resource estimations during feeding period without carrying out controlled fishing.