The Wisdom of Thanos in Fishery Science: Why Manage Catch-and-Release Fisheries?

In the Marvel Comics movie "Avengers: Infinity War," the god-like character Thanos regulates resources by eliminating half the human population. The goal (not the mechanism) is shared with fishery scientists who labor to allocate resources fairly and sustainably in open-access fisheries. Minimizing human exploitation is perceptively easier via catch-and-release fishing. This widespread and voluntary form of fishing has improved sustainability of Largemouth Bass Micropterus salmoides. As a fishery manager for bass in Maryland, I therefore asked whether scientists need to manage catch-and-release fisheries. I used an age-structured population model to test for circumstances under which catch-and-release fishing may not sustain Largemouth Bass populations. As was observed for a wild riverine population, I found that low to moderate levels of exploitation (e.g., catch-and-release mortality) could cause negative impacts when habitat loss also restricted recruitment. Although Thanos may have been wrong when thinking that reduced exploitation always leads to more resources, the wisdom in that admission encourages fishery and environmental agencies to jointly manage fish habitat and ensure the sustainability of sport fish.