Methodological Validation And Comparative Analysis Of Gravimetric, Volumetric, And Von Bayer's Techniques For Seasonal Fecundity Estimation In Cyprinus Carpio In Kasarwadi Reservoir, Parli.V Dist – Beed.

Abstract

Precise estimation of egg volume and fecundity is central to reproductive biology, stock assessment, and recruitment modeling in Cyprinus carpio, a highly fecund and economically important freshwater teleost. Because common carp produce large numbers of small, morphologically uniform eggs, methodological accuracy in egg quantification directly influences interpretation of maternal investment, spawning potential, and population productivity. Despite widespread application of subsampling-based fecundity techniques, comparative validation of egg volume estimation methods under reservoir conditions remains limited.

The present study provides a comprehensive methodological evaluation of three standardized egg-measurement approaches—gravimetric, volumetric, and Von Bayer’s micrometric methods—applied to ovarian samples of C. carpio collected seasonally from Kasarwadi Reservoir. The gravimetric method estimated fecundity through proportional extrapolation of egg counts from weighed ovarian subsamples to total ovary mass, whereas the volumetric method employed water-displacement–based volume subsampling to derive total egg number. The Von Bayer method involved calibrated microscopic measurement of oocyte diameter followed by geometric computation of individual egg volume, enabling high-resolution morphometric analysis. Replicate subsampling (n = 25 per dataset) was performed to enhance statistical robustness and minimize intra-ovarian heterogeneity bias.

Comparative statistical analyses demonstrated strong positive correlations among estimates generated by all three methods, confirming their general reliability for fecundity determination. However, methodological sensitivity differed: gravimetric and volumetric techniques provided rapid, cost-effective, and field-applicable estimates suitable for large sample sizes, but their accuracy depended on uniform egg distribution and careful subsampling. In contrast, the Von Bayer’s micrometric approach yielded superior precision in egg diameter and volume estimation and allowed detection of intra-ovarian variability, making it particularly valuable for detailed reproductive and morphometric studies. Seasonal trends revealed peak fecundity during the monsoon (spawning) phase and reduced reproductive output during winter, consistent with environmentally regulated carp reproductive cycles.

The findings establish an integrated methodological framework for standardized egg volume and fecundity assessment in C. carpio. While gravimetric and volumetric methods are recommended for large-scale reproductive surveys, the Von Bayer technique serves as a reference standard for precise egg morphometry. Adoption of combined methodological strategies enhances analytical reliability, strengthens reproductive evaluation, and supports evidence-based fisheries management and hatchery optimization in reservoir ecosystems.