Data from: Making sense of the relationships between Ne, Nb and Nc towards defining conservation thresholds in Atlantic salmon (Salmo salar)

Effective population size over a generation (Ne) or over a reproductive cycle (Nb), and the adult census size (Nc) are important parameters in both conservation and evolutionary biology. While Ne provides information regarding the rate of loss of genetic diversity and can be tracked back in time to infer demographic history of populations, Nb may often be more easily quantified than Nc for short-term abundance monitoring. In this study, we propose i) an empirical context to Waples et al. (2014), who introduced a correction to bias due to overlapping generations, and ii) a mathematical relationship between Ne and Nb for direct application in Atlantic salmon populations in Québec, Canada. To achieve this, we investigate the relationships between Ne, Nb, and Nc in 10 Atlantic salmon populations, Canada, for which we genotyped 100 randomly sampled young-of-the year individuals for 5 consecutive years. The results show a positive correlation between Ne, Nb and Nc suggesting that Nb is an indicative parameter for tracking effective population size and abundance of Atlantic salmon. However, our model allows predicting Nc from Nb values at 27 %, which can be partly explained by high variance in Nb/Nc both among populations (37 %) and among years (19 %). This result illustrates the need for thorough calibration of Nb/Nc before using Nb in monitoring programs, as well as a full understanding of the limits of such an approach. Finally, we discuss the importance of these results for the management of wild populations.