Economic evaluation of barriers to minimize reservoir sport fish escapement

Abstract

Barriers can be an effective method for reducing escapement of reservoir sport fish; however, whether the financial benefits of a barrier outweigh the costs of a barrier is unknown. We sought to quantify the costs and benefits associated with constructing barriers to reduce fish escapement while explicitly accounting for variability and uncertainty.We developed a framework using simulation modeling and discounted cash flow techniques to quantify the costs and benefits of barrier construction on Brushy Creek Lake, Iowa, where a barrier was constructed in 2020 to reduce escapement of stocked Walleye Sander vitreus and Muskellunge Esox masquinongy. We then incorporated this framework into an interactive Shiny application to enable cost–benefit evaluations across a wide range of barrier types, system types, species, and escapement rates.The present value of the parallel‐bar barrier on Brushy Creek Lake, Iowa, over 10 years was US$69,576 (range = $64,484–$73,976), whereas the present value of escaped fish was $316,416 ($253,459–$378,823), indicating a net benefit of $246,840 ($188,975–$304,847) associated with barrier construction. The benefit–cost ratio of barrier construction was 4.55 after 10 years, indicating that for every $1 in present value spent on barrier construction, we saved $4.55 by preventing fish escapement. There was a 99% probability of a positive mean net benefit of the barrier after 3 years.Our results indicate that barriers can be a cost‐effective option to minimize fish escapement, and barrier costs are more predictable compared with the cost of escapement. Quantifying the value of escaped fish and barrier construction on an economic scale enables the use of formal decision‐making tools to address complicated and multifaceted issues associated with reservoir fisheries management.