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bioRxiv · 10.64898/2025.12.17.695007

Bent Hockey-Stick Stock-Recruitment Function

Okamura, H.·Nishijima, S.·Ichinokawa, M.
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Abstract

The hockey-stick is a simple and widely applicable stock-recruitment function. One drawback is its non-differentiability at the breakpoint, which can be especially problematic when using state-space models for stock assessment. Here, we develop a new bent hockey-stick model that retains the desirable properties of the original hockey-stick function while providing a differentiable breakpoint. We also propose a new algorithm for estimating MSY under multiplicative process stochasticity in the stock-recruitment relationship. Simulation studies demonstrate the utility of these approaches, which can substantially enhance the robustness and sustainability of fisheries management.

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Okamura, H., Nishijima, S., Ichinokawa, M.. 2025-12-19. Bent Hockey-Stick Stock-Recruitment Function. https://doi.org/10.64898/2025.12.17.695007

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