A histological study of development of oocytes in capelin, Mallotus villosus villosus (Müller)

• Published in: Journal of Fish Biology
• Main Author: Forberg, K. G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1982
• Subjects: Barents Sea
• Online Access: http://dx.doi.org/10.1111/j.1095-8649.1982.tb03915.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.1982.tb03915.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1982.tb03915.x

Female capelin, Mallotus villosus villosus , were sampled at various times of the year from the Barents Sea and preserved for histological examination. The current paper describes various stages of development of capelin oocytes. The description can be used as the basis for the preparation of a maturity scale to be used in the field, using whole oocytes and low power microscopy. The development of the oocytes is classified into 10 stages according to morphological characters. First growth phase oocytes are always present in the ovaries, showing that female capelin have a potential for several spawnings. Second growth phase oocytes grow synchronously. Oocytes of‘ Yolk vesicle stage I‘ are suggested to be the first stage of second growth phase which lasts for somewhat less than one year, and ends with spawning.