ABSTRACT: The hypothesis was tested that flatfish nursery ground carrying capacity was not reached for juvenile flatfish populations at the productive Balgzand intertidal (Dutch Wadden Sea). Dynamic self-thinning lines (the logarithmic relationship between the annual development of population density and mean individual weight) were estimated over the period 1975-2019, whereby a slope of -4/3 would indicate that carrying capacity was reached. In 0-group plaice Pleuronectes platessa L. a decrease in slope occurred from on average -2.69 in the 1980s to -0.81 in the 2010s. In 0-group flounder Platichthys flesus (L.) slopes increased from -0.98 on average in the 1980s to -1.77 in the 2010s. Slopes indicated that flatfish nursery ground carrying capacity was not reached at the Balgzand intertidal. This in contrast to British bays, most likely because of a lower benthic food biomass in British bays (few g dry mass per m²) compared to Balgzand (tens of g dry mass per m²). Interannual differences in slope of the dynamic self-thinning lines at Balgzand reflected changes in density during the season. Over the period 1975-2019 the average daily instantaneous rate of change in 0-group flounder reflected mortality and was about 0.042 d^-1, however with large interannual variations. In 0-group plaice rate of change in density was 0.020 d^-1 in the 1970s, also reflecting mortality, but increased over time due to increased emigration. Dynamic self-thinning lines can be used to analyse flatfish nursery ground carrying capacity, however in many flatfish nursery grounds, carrying capacity will presently not be reached.