Knowledge gaps in economic costs of invasive alien fish worldwide

Andrew M. Kramer,Rodolphe E. Gozlan,Christophe Diagne,Melina Kourantidou,Franck Courchamp,Laura N.H. Verbrugge,Ross N. Cuthbert,Camille Bernery,Phillip J. Haubrock,Chunlong Liu,Anna J. Turbelin,Boris Leroy

doi:10.1016/j.scitotenv.2021.149875

Abstract

Invasive alien fishes have had pernicious ecological and economic impacts on both aquatic ecosystems and human societies. However, a comprehensive and collective assessment of their monetary costs is still lacking. In this study, we collected and reviewed reported data on the economic impacts of invasive alien fishes using InvaCost, the most comprehensive global database of invasion costs. We analysed how total (i.e. both observed and potential/predicted) and observed (i.e. empirically incurred only) costs of fish invasions are distributed geographically and temporally and assessed which socioeconomic sectors are most affected. Fish invasions have potentially caused the economic loss of at least US$37.08 billion (US2017 value) globally, from just 27 reported species. North America reported the highest costs (>85% of the total economic loss), followed by Europe, Oceania and Asia, with no costs yet reported from Africa or South America. Only 6.6% of the total reported costs were from invasive alien marine fish. The costs that were observed amounted to US$2.28 billion (6.1% of total costs), indicating that the costs of damage caused by invasive alien fishes are often extrapolated and/or difficult to quantify. Most of the observed costs were related to damage and resource losses (89%). Observed costs mainly affected public and social welfare (63%), with the remainder borne by fisheries, authorities and stakeholders through management actions, environmental, and mixed sectors. Total costs related to fish invasions have increased significantly over time, from <US$0.01 million/year in the 1960s to over US$1 billion/year in the 2000s, while observed costs have followed a similar trajectory. Despite the growing body of work on fish invasions, information on costs has been much less than expected, given the overall number of invasive alien fish species documented and the high costs of the few cases reported. Both invasions and their economic costs are increasing, exacerbating the need for improved cost reporting across socioeconomic sectors and geographic regions, for more effective invasive alien fish management.

Highlights

Invasive alien fish introductions are increasing in number globally (Leprieur et al, 2008; Avlijaš et al, 2018)
We examined the costs in terms of the year of impact, which reflects the time at which the invasion cost likely occurred and extended it over years in which the costs were realised using the summarizeCosts function of the ‘invacost’ R package
The majority of costs was deemed as potential (US $34.79 billion; n = 88, hereafter the number of cost entries), while observed costs amounted to only US$2.28 billion (n = 296)

Summary

Introduction

Invasive alien fish introductions are increasing in number globally (Leprieur et al, 2008; Avlijaš et al, 2018). Despite evidence for increasing numbers of fish invasions worldwide and their growing ecological impacts (Leprieur et al, 2008; Seebens et al, 2020; Raick et al, 2020), their economic impacts remain poorly understood, largely due to a lack of data for numerous sectors and difficulties in monetizing ecological impacts. This paucity of cost data has led to debate among scientists about previous estimates of invasion costs (Cuthbert et al, 2020), which have often relied on over-extrapolation and presented untraceable sources. In the context of fisheries, this could involve projecting costs from local scales to entire fisheries

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Discussion

Conclusion