Introduction and objectives
The genetic improvement of the ratio of the edible part in shrimps is presently not undertaken in commercial breeding programs (Ren et al., 2025). We aim to fill this gap by estimating genetic parameters of abdominal yields and morphological predictors of those in the Pacific blue shrimp (Penaeus stylirostris) based on lengths measured by electronic caliper or on digital images, also integrating water loss after cooking. With these parameters, we estimate expected genetic gains on abdominal yields by sib-based selection or by mass selection on the predictor.
Material and methods
A total of 49 full and half-sib families were created by inseminating each dam with spermatophores from 2 sires (Haffray et al. 2025 and 2026). A sample of 1200 progenies were assigned to their parents with SNP markers and phenotyped at commercial size (≈ 14.5 g) by measuring body length and abdominal length on uncooked individuals, either with an electronic caliper or by computer vision from 2D pictures. The whole shrimps were weighted uncooked or after cooking by boiling, and abdomen weight was measured after cooking. We calculated the ratio of the cooked abdominal weight either to the uncooked body weight or to the cooked body weight. The water loss ratio after cooking was also calculated as the difference between uncooked and cooked body weights divided by uncooked body weight. We estimated genetic parameters for these traits and genetic gains obtained either by sib-based selection on tail yield or mass selection on the residual of the regression of abdominal length to total length.
Results
Heritability estimates were intermediate for the ratio of the cooked abdominal weight to the raw or cooked body weights(0.33-0.24), and lower when considered as residuals of the numerators to the denominators (0.20 and 0.12). The heritability of the ratio of abdominal length to total length increased when using computer vision instead of the electronic caliper (0.20 vs 0.07). The genetic correlations between predictors and the yields or residuals to predict were high (0.67-0.94) and higher when the predictors werere measured by computer vision.
The simulated genetic gains per generation were similar between sib-selection and mass selection at similar selection pressures and increased with the increased selection pressure permitted by mass selection (10-30 %), compared to lower selection pressure possible by sib-selection (30-50 %).
Conclusions and perspectives
These results show it is possible to geneticallyto improve abdominal yield by mass or by sib selection in the Pacific blue shrims. The short interval of generation in shrimp is favorable for it progressive and slow improvement to better characterize potential impacts on other traits or relative organs development. The simple and highly genetically correlated indirect predictor evaluated is promising and future advances in 3D vision and AI may further improve phenotyping accuracy and increase heritability of future predictors. The negative genetic correlation between water loss at cooking and uncooked abdominal yield is also paving the way to better characterize the interaction between improvement of yields and flesh quality traits.
Acknowledgment
This research was supported by the Technopole of New Caledonia. None of the experiments would have been possible without the cooperation of Thomas Pierrot from the Technopole and stimulating discussion with Alain Michel and Herv�� Lucien-Brun.
References
Haffray, P., Enez, F., Mahunon, H., Lorgeoux, B., Blanc, P.P., Genestout L., Rivaton, A., Bugeon, J., Haag-Liautard, C., Gagnaire, P-A., Vandeputte, M., 2025. High residual additive genetic variability in a Pacific blue shrimp Litopenaeus stylirostris population after 36 generations of domestication from only 4 estimated founders. Aquaculture. https://doi.org/10.1016/j.aquaculture.2025.742835
Haffray, P., Enez, F., Lorgeoux, B., Thillier, M., Claveau J.B., Schembri, F, Blanc, P.P., Rivaton, A., Bugeon, J., Vandeputte, M., 2026. Genetic variation in molting time and its effects on growth and color traits in the Pacific blue shrimp Litopenaeus stylirostris. Aquaculture, 614, 743479. https://doi.org/10.1016/j.aquaculture.2025.743479
Ren, S., Y����ez, J.M., Perez-Enriquez, R., Rye, M., Houston, R.D., Hurwood, D.A., Gonzalez-Galaviz, J.R., Salazar, M., Max- Aguilar, A., Wade, N.M., Jerry, D.R., 2025. 100 years of penaeid domestication and meta-analysis of breeding traits. Reviews in Fisheries Science & Aquaculture. https://doi.org/10.1080/23308249.2025.2497273