Harvesting the wild populations reduces the frequency of the desired phenotypes. Artificial breeding in order to increase the frequency of the desirable phenotypes. Unnatural selection selection against desirable phenotypes resulting in reduced body size etc . Might result in a longer time needed for recovery because harvesting causes strong selection differentials: harvesting management, monitoring programs to detect exploitation. Individuals of a certain morphology are more likely to be removed from the population by harvest. The most productive animals are used as breeding stock as practice with the goal of increasing the frequency of the desired phenotype (in agriculture) 3 types of selection: methodological, unconscious, natural not affected by human influence. Sexual and natural selection act simultaneously to change the frequency of particular phenotypes. Limits of biological knowledge and control influence exploitation and our ability to control it. Because the main goal is sustainable yield, focus on demographics was important.