Optimal harvesting in a changing climate

Am Lee,Be Sæther

doi:10.3354/cr01658

Abstract

Choosing the right harvesting strategy is crucial for sustainable utilization of biological resources but is challenging in real systems with fluctuating environments. This challenge is expected to become even greater with global warming, as environmental variability is predicted to increase. Additionally, harvesting strategies based on single-species models have been shown to carry a severe risk of species extinctions when species interactions are ignored, particularly in systems with more than one harvested species. As the climate continues to warm, we therefore need new reference points for harvesting in an ecosystem context with environmental fluctuations. In this paper, we discuss the development of harvesting strategies and suggest that a proportional threshold harvesting framework could be a useful starting point for developing such reference points and tackling the challenge of sustainable harvesting in the future.

Highlights

One of the most central topics in harvesting theory and resource management over the past decades has been how to choose the best harvesting strategies
The challenge is to find a strategy that maximizes some measure of yield without endangering the future growth of the harvested population. This is challenging in fluctuating environments, as such fluctuations add an extra source of uncertainty and stochasticity to the fluctuations in population size
It became clear that random variation in the environment has major implications for the best choice of harvesting strategy. These analyses demonstrated that assumptions about underlying population dynamics strongly affect the predicted population consequences of a given harvest strategy

Summary

INTRODUCTION

One of the most central topics in harvesting theory and resource management over the past decades has been how to choose the best harvesting strategies. Projected climate changes are expected to cause altered population dynamics in many commercially important exploited species This will affect mean population sizes and patterns in the population fluctuations, which will be strongly influenced by changes in the temporal variability of the environment (Hansen et al 2019). Once a strategy has been chosen, it is essential to evaluate its implementation, both in terms of direct impacts (numbers and distribution of actual harvest offtake) and subsequent population responses. This should be done within a framework of adaptive management and strategic foresight with stakeholder involvement (Hamel et al 2022 in this Special)

OPTIMAL HARVESTING STRATEGIES

CONCLUSIONS