A New Approach to Evaluate Reproductive Traits in Batch-Spawning Fishes of Indeterminate Fecundity and Asynchronous Oocyte Maturation

Abstract

Fishes are characterized by a great diversity of reproductive strategies that often make fecundity evaluation difficult. Unlike marine fishes, a single consensual concept of terminology and definitions is lacking for freshwater fish fecundity. Several approaches are known from scientific literature for evaluating fecundity in batch spawning fishes of indeterminate fecundity and asynchronous oocyte maturation. These methodological differences impose a bias on the outputs of comparative studies of fecundity. For both theoretical and practical reasons, accurate fecundity data are required to inform the decision-making process in terms of environmental policy and the related applications for the control of non-native species and the conservation management of native species and ecosystems. The main aim of the present study was to review briefly the existing fecundity-evaluation methods, to test among-method compatibility, and to develop a new approach that aims to make fecundity evaluation more systematic and transparent. A simulated ‘test’ dataset demonstrated considerable variability in the results obtained from the various existing approaches. The literature review and our analyses revealed a need for standardization. Thus, a new approach is proposed here that is based on multiple sampling throughout the reproductive cycle; provides greater overall detail of the species’ reproductive traits and permits inter-population comparisons.

Keywords:

• Indeterminate fecundity
• new fecundity evaluation approach
• freshwater fishes

Acknowledgements

English was revised and corrected by G. H. Copp who also provided important suggestions to the earlier versions of this manuscript that improved the organisation of the manuscript considerably.

Authors' contributions

KHZ brought the idea to propose the new approach, performed data analyses and calculations, and wrote the first draft of the MS, KS performed calculations and analyses, and contributed to the first draft of the MS, DH made all statistical analyses and contributed to the text of the MS, VK proposed the concept of the MS and edited the text. All authors read and approved the final manuscript.

Disclosure statement

The authors declare that they have no conflict of interest.

Data availability statement

All data and material originate from our own research activities funded by scientific grant agencies mentioned in Funding details and/or from literary data publicly available.

Data deposition

https://data.mendeley.com/datasets/ssbyp29899/1

Additional information

Funding

This work was supported by the Slovak Scientific Grant Agency VEGA (Project 1/0640/16); the RECETOX research infrastructure (the Czech Ministry of Education, Youth and Sports; LM2018121); and CETOCOEN EXCELLENCE Teaming 2 project (Horizon 2020; 857560 and the Czech Ministry of Education, Youth and Sports; CZ.02.1.01/0.0/0.0/17_043/0009632).