Acta Ichthyologica et Piscatoria 19(2): 21-28, doi: 10.3750/AIP1989.19.2.02
Changes of gonadosomatic index (GSI) and egg diameter in the grayling Thymallus thymallus (L.) in annual cycle
expand article infoA. Witkowski, J. Błachuta, B. Kokurewicz, M. Kowalewski

Corresponding author: A. Witkowski

© A. Witkowski, J. Błachuta, B. Kokurewicz, M. Kowalewski.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Witkowski A, Błachuta J, Kokurewicz B, Kowalewski M (1989) Changes of gonadosomatic index (GSI) and egg diameter in the grayling Thymallus thymallus (L.) in annual cycle. Acta Ichthyologica et Piscatoria 19(2): 21-28. https://doi.org/10.3750/AIP1989.19.2.02
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Abstract
The most intense growth of grayling ovaries takes place in autumn and winter (September-March), of testes-in summer (July-September). Older females and males all seasons have a higher GSI, and the diameter of developing eggs is higher.