Michigan Aquatic Pest Control Practice Exam

The two probable causes of stunting in bluegills or other sunfish relate to large predators being unavailable and the presence of dense stands of weeds. When large predators are not present in a given aquatic ecosystem, smaller fish like bluegills can reach high population densities. This situation often leads to increased competition for limited resources such as food and space, which can hinder the growth of individual fish and result in stunted growth.

Additionally, dense stands of aquatic weeds can provide cover and habitat for smaller fish, allowing their populations to thrive unchecked. While the cover is beneficial for the fish, it can also contribute to limited access to food sources due to competition with other individuals in the population. In combination, these factors can significantly impact the overall health and growth potential of bluegill populations, leading to stunting.

Other options include various environmental stressors or factors that can influence fish populations, but the presence of large predators and dense weed growth specifically addresses the issue of growth inhibition in bluegills and similar species effectively.