Social–ecological feedbacks drive spatial exploitation in a northern freshwater fishery: A halo of depletion

Abstract

1. Freshwater fisheries are complex social-ecological systems spatially structured by coupled feedbacks between people and nature. Spatial exploitation dynamics depend on angler preferences for multiple attributes that influence their site choices.Anglers then reciprocally impact local fish populations through size-selective catch and harvest. Thus, feedbacks among angler site choices, their capture efficiency (i.e. catchability) and fish population dynamics permeate through whole landscapes.2. We studied the coupled feedbacks and effects of spatial exploitation in an iconic northern freshwater fishery of conservation concern. Specifically, we evaluated several coupled feedbacks in the spatially structured Yukon lake trout fishery using a Bayesian multinomial choice model fitted to onsite interviews and fishery-independent population assessments to identify whether: (a) trip context (day vs. multi-day trips) shaped angler preferences and site choices, (b) catch-based quality was influenced by a sizenumbers trade-off and density-dependent catchability and (c) fish population structure was associated with the gravity of resource usage resulting from spatial exploitation.3. Overall, we found that angler site choices were shaped by preferences for multiple characteristics including travel time and catch-based quality. Angler preferences also varied with trip contexts-for example, anglers on day trips were less willing to travel than anglers on multi-day trips. We detected strong density-dependent catchability, which led to hyperstable catches and relatively few anglers dominated most of the catch.4. There was a strong demographic trade-off between lake trout body size and abundance that appeared to dynamically interact with anglers' size-selective preferences for larger lake trout. Coupled feedbacks among angler site choices, sizeselective and hyperstable catches, and density-dependent growth and survival appeared to structure spatial exploitation patterns leading to a halo of depletion in fish body sizes and fishing quality near urban centres. Synthesis and applications.Feedbacks between fish and anglers affected spatial exploitation patterns leading to a halo of depletion in Yukon lake trout. We recommend | 207Journal of Applied Ecology WILSON et aL.

Recreational angler satisfaction: What drives it?

“…This finding is consistent with evidence from studies on aggregated angling effort dynamics in response to changes in fish abundances (e.g. Mee et al., 2016; Post et al., 2008; Wilson et al., 2020) and is also supported by research showing that catch is very important to most anglers when choosing a fishing site (Hunt et al., 2019). Catch satisfies many different aspects of the fishing experience.…”

Temporal invariance of social‐ecological catchments

“…The proximity of beavers to cottonwood ( Populus fremontii ) populations ultimately shapes cottonwood reproduction and population dynamics. For social‐ecological systems such as recreational fisheries, angler travel time and trip context (day vs. multi‐day) can create strong coupled feedbacks between anglers and waterbodies, leading to halos of fish depletion near urban centers (Wilson et al 2020). We provide further evidence that location and proximity between people and natural resources is a prominent and important feature that ultimately contributes to the structuring of social‐ecological systems.…”

“…The proximity of beavers to cottonwood (Populus fremontii) populations ultimately shapes cottonwood reproduction and population dynamics. For social-ecological systems such as recreational fisheries, angler travel time and trip context (day vs. multi-day) can create strong coupled feedbacks between anglers and waterbodies, leading to halos of fish depletion near urban centers (Wilson et al 2020). We March 2021 STRUCTURED ANGLER-RESOURCE RELATIONSHIPS Article e02272; page 3…”

Direct evidence of a prey depletion “halo” surrounding a pelagic predator colony

“…This theoretical prey gradient is commonly referred to as "Ashmole's halo" (12) and has been highly influential in shaping our understanding of the population dynamics, behavior, and life histories of seabirds (6,8,(11)(12)(13)(14) and other colonial centralplace foragers [e.g., seals (9), raptors (15), and human fishers (16)]. However, almost six decades since it was proposed, direct evidence that such "halos" form in nature is extremely scarce.…”