University of Tasmania
139430 - Development of a new 'ultrametric' method for assessing spawning progression in female teleost serial spawners.pdf (3.09 MB)

Development of a new 'ultrametric' method for assessing spawning progression in female teleost serial spawners

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journal contribution
posted on 2023-05-20, 15:09 authored by Kelli AndersonKelli Anderson, Alix, M, Charitonidou, K, Thorsen, A, Thorsheim, G, Ganias, K, dos Santos Schmidt, TC, Kjesbu, OS
The collection and presentation of accurate reproductive data from wild fish has historically been somewhat problematic, especially for serially spawning species. Therefore, the aim of the current study was to develop a novel method of assessing female spawning status that is robust to variation in oocyte dynamics between specimens. Atlantic cod (Barents Sea stock) were used to develop the new ‘ultrametric’ method, that is based on the progressive depletion of the vitellogenic oocyte pool relative to the rather constant previtellogenic oocyte (PVO) pool. Fish were subsequently partitioned into one of four categories that accurately reflected changes in their oocyte size frequency distribution characteristics and gonadosomatic index throughout spawning. The ultrametric method overcomes difficulties associated with presence of bimodal oocyte distributions, oocyte tails, lack of clear hiatus region, and presence of free ova, and can be implemented at a single sampling point. Much of the workflow is fully automated, and the technique may circumvent the need for histological analysis depending on the desired outcome. The ultrametric method differs from the traditional autodiametric method in that PVOs can be separated by ultrasonication and then enumerated, and ovarian homogeneity is not a mandatory requirement per se. The method is designed for determinate spawners but might be extended to include indeterminate spawners.


Publication title

Scientific Reports



Article number









Institute for Marine and Antarctic Studies


Nature Publishing Group

Place of publication

United Kingdom

Rights statement

Copyright 2020 The Authors. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0)

Repository Status

  • Open

Socio-economic Objectives

Wild caught fin fish (excl. tuna); Expanding knowledge in the biological sciences