Large variation in stock dynamics affects the accuracy of stock estimates, which fisheries managers rely on when determining quotas and other regulations. The purpose of this paper is to investigate the implications of uncertainty on pulse fishing. We show that as the variance of the random natural fluctuations increases, the optimal pulse length decreases and converge toward a constant-escapement policy. Hence, in fisheries with large natural variability, a constant-escapement policy is a good approximation of the optimal policy.