During the reproductive season, animals have to manage both their energetic and gametic budgets. In particular, for semelparous capital breeders with determinate fecundity and no parental care, the depletion of energetic stock must match the depletion of gametic stock, so that individuals get exhausted just after their last egg is laid. Although these budgets are managed continuously, monitoring the dynamics of mating acts and energy expenditure at a fine temporal scale in the wild is

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... g. The goal of this study was to quantify the individual dynamics of spawning acts and the concomitant energy expenditure of female Allis shad (Alosa alosa) throughout the mating season in a short river. Tri-axial acceleration, temperature and pressure data collected by eight individual-borne accelerometers for one month were analysed to i) detect the timing of spawning acts, ii) estimate energy expenditure from tail beat frequency and water temperature, and iii) monitor changes in body roundness. Female shad performed on average 15.75 spawning acts, in 4.87 short volleys of 3.23 acts separated by 3.55 resting nights. The timing of spawning acts was influenced by oocyte maturation, temperature and social factors. Shad were more active at night and in warmer water. According to an energetic model based on American shad (Alosa sapidissima), they consumed on average 0.19 kJ.min-1 and 7193 kJ over one month of spawning activity, but parameters from American shad may not be adapted to Allis shad. They died on average four days after their last spawning act, having lost 42% of their weight, but all with residual oocytes. The acceleration-based indicator of body roundness was correlated to condition coefficient, and globally decreased through the spawning season, although the indicator was noisy and did not match changes in energy expenditure.