This method of population estimation would be more accurate in a lake setting as the fish would all stay at the same place all the time so it's easier to keep a control of the population.
Explanation:
The mark and recapture method is a population size estimation technique where a portion of the population is marked and released, and then a second portion is captured to count how many of the previously marked individuals is found in order to determinate an estimate of the total size of the population. Doing this on a stream or river would present several complications, as the individuals are constantly moving ahead down the river and travel very long distances, so the probability of recapturing a previously marked individual is very slim. Whereas in a lake, all the population of fish would stay in the same area all the time, making this method very practical to estimate the total population.
