Fishermen are often advised to be more patient and limit catches now, in order to increase stock size and catches in the future. Such scientific advice is usually based on the maximum sustainable yield (MSY) objective. This biological criterion is often consistent with economic interests at low discount rates. The aim of this paper is to check if fishery managers are as patient as they advise fishermen to be. To answer this question, we performed a field experiment with 474 members of the ICES community, which is the major scientific advice-giving organization in North-Atlantic fisheries. Using an online questionnaire, we performed a simple economic experiment to reveal the time-preferences (i.e. interest rates) of scientists. Variability in stated time-preferences was high, with interest rates ranging from zero to >50%. More than 40% of the ICES community opted for interest rates >10%. We apply the observed interest rates in age-structured bio-economic models of two important cod fisheries and find that the long-term optimal spawning stock biomass is drastically lower than in the MSY base case for interest rates >10%. It seems that there is some evidence of preaching water while drinking wine in the fisheries management sector.