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Contributed Talk

Session: : Fisheries Management And Models 2

COS 304-2 - Assessing ecological and economic benefits of different fishery management policies on the fishery with heterogeneous fishers using a network based approach

Thursday, August 10, 2023
3:45 PM – 4:00 PM PDT
Location: E141
Abstract: Relative to traditional single-species management approaches, ecosystem based fisheries management (EBFM) has emerged in recent years as a recommended holistic approach for conferring long term ecological and economic benefits. However, understanding beyond the qualitative benefits of EBFM requires a deeper understanding of both the ecological interactions and the interactions with humans who rely on these ecological resources. These complex interactions are often highlighted but theoretical work to incorporate these is still lacking. Here, we present a model which captures both ecological interactions and human interactions who rely on these resources. We incorporate ecological connectivity between species in the form of a trophic food web using the Niche Model which is governed by a set of ordinary differential equations with parameterized rates using Allometric Trophic Network models. The human system consists of fishers whose fishing efforts grow or shrink in response to profits, which depend on the ecological state of the target species. We include two features which are often ignored in harvest models: unintentional bycatch of a potentially vulnerable species during commercial fishing and information heterogeneity amongst fishers, which determines their relative successes at harvesting target commercial species while avoiding bycatch. We consider different fishery management policies governing the harvest of the target species and the bycatch species. We assess the different ecological and economic consequences of these policy alternatives, in terms of ecological species extinctions and longevity of fishery to sustain commercial fishing. We also consider how outcomes are influenced by the economics of the fishery, namely the cost of fishing. We present results relative to a benchmark scenario where there are no management policies in place, i.e., open access. We find that if the relative cost of fishing effort is high, then the target and bycatch species extinctions are mitigated as long as there’s a shared quota on target species, irrespective of whether bycatch species are managed separately. Furthermore, the secondary extinctions, which are extinctions of ecological species (other than target and bycatch species) due to indirect effects of fishing on the food webs, is also much smaller and independent of whether bycatch species are managed separately. The framework of our model would allow policymakers to evaluate different management approaches, without compromising on the ecological complexities of a fishery and provide insights into how we could mitigate species extinctions.