Editor’s Choice 57:02 – Understanding anglers as spatially mobile human predators in freshwater landscapes

Using the example of a spatial recreational fishery for lake trout in northern Canada, Wilson et al. present an exciting analysis of how human behaviour and local ecological dynamics interact to shape landscape-level outcomes. Associate Editor, Robert Arlinghaus highlights why this article has been selected as an Editor’s Choice.

The field of applied ecology is increasingly moving towards studies that integrate human behaviour and ecological dynamics, and the paper by Wilson et al. constitutes an extraordinary case. Drawing on concepts from behavioural ecology, the authors examine the dynamics of how human foragers (anglers) interact with a spatially structured fishery (lake trout populations in different lakes).

The authors draw on choice models, informed by resource economics, to show the determinants of angler site choice behaviour. They show that anglers differ in what drives their behaviour depending on whether single or multiple-day trips are chosen. In both cases, however, distance, presence of facilities and the expectations about what to catch affects where anglers go and how intensively they fish. Importantly, the authors show that, besides distance, it is the expected size of the fish and not the expected catch rates that affects the fishing pressure for lake trout. This is noteworthy as the fitness function of the human predator substantially departs from what a natural predator would normally seek.

While the anglers desire the rarer catch of a particularly large lake trout, most other predators would go for maximizing the intake rate (or catch rates) per unit effort while accounting for travel costs and other issues. Therefore, if we are to understand how anglers (or hunters) interact with natural resources, we have to use social science methods and avoid assuming analogies from natural foragers.

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Photo: Kyle Wilson

Wilson et al. also show that the complex interactions of angler decision-making, and the way exploited trout populations respond to exploitation through density- and size-dependent processes, lead to characteristic outcomes at the landscape level that cannot be easily predicted from classical theories such as the ideal free distribution. For example, lakes that happen to be situated in closer proximity to large latent angling efforts experience more severe declines in lake trout size (and hence overfishing) than more remote fisheries. This in turn means that management approaches must be spatially explicit and tailored towards the interplay of humans and ecosystems, as moderated by the local effort density potential.

This work constitutes an outstanding empirical demonstration of several theoretical predictions by Matsumura et al. that suggest homogenization of local abundances (and hence catch rates) must not be expected when the forager population target fish sizes, and not abundance (or catch rate). However, because the human forager population was also shown to show ‘hyperstable catch rates’, i.e., patterns maintaining large catch rates despite declines in abundance due to overfishing, population crashes may not be easily indicated by monitoring average angler catch rates. This constitutes a continued challenge for resource management, which can only be solved by monitoring not only catch rates but also the type of forager (angler) that is using local fisheries.

The article by Wilson et al. constitutes a prime example of an unusually data-rich paper that tracks both humans and natural resources, confirming theory developed for such type of systems and at the same time constituting an eye-opening example of how human behaviour can produce exceedingly complex landscape-level outcomes in spatially structured natural resource systems that challenge resource management and calls for new approaches to govern such complex adaptive systems.

The full Editor’s Choice article, Social–ecological feedbacks drive spatial exploitation in a northern freshwater fishery: A halo of depletion, is free to read for a limited time in Journal of Applied Ecology.

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