Exploring Overestimation of Harvested Populations from the Use of Single-Species Model Management

Undergraduate Honors Thesis

Citations

Citeable URL: https://scholar.colorado.edu/concern/undergraduate_honors_theses/p2676x019

Abstract

Harvested fish populations have dynamics that are hard to predict due to the complexity of the ecosystems in which they are found. Single-species models are used to assess the health of these populations. Single-species models ignore other environmental factors within the system, and solely focus on the harvested population, which leads to inaccurate calculations of the populations dynamics. Single-species models are used to predict the Maximum Sustainable Yield (MSY) of the population, which is the maximum catch of the population that can be sustained biologically. If managers overestimate MSY, this could unintentionally cause the depletion of the population. In this paper, we investigate whether we should expect single-species models overestimating MSY to be a general phenomenon. We use a simplified analytical model to explore the dynamics of fisheries populations, which managers wrongly assume have single-species dynamics, comparing estimated and ‘true’ MSYs. We found that there are four general cases. Two of these cases result in the manager overestimating MSY, and we argue these cases are the most common in real fisheries. Our results give a helpful insight into how we can anticipate errors when using single-species models to manage fish populations.

Creator