Missing the Boat on Freshwater Fish Conservation in California

Theodore E Grantham,Ryan Peek,Kurt A Fesenmyer,Joshua H Viers,Peter B Moyle,Andy Bell,Eric Holmes,Rebecca M Quiñones,Jeanette K Howard,Nick Santos

doi:10.1111/conl.12249

Abstract

AbstractPopulation growth and increasing water‐use pressures threaten California's freshwater ecosystems and have led many native fishes to the brink of extinction. To guide fish conservation efforts, we provide the first systematic prioritization of river catchments and identify those that disproportionately contribute to fish taxonomic diversity. Using high‐resolution range maps of exceptional quality, we also assess the representation of fish taxa within the state's protected areas and examine the concordance of high‐priority catchments with existing reserves and among distinct taxonomic groups. Although most of the state's native fishes are found within protected areas, only a small proportion of their ranges are represented. Few high‐priority catchments occur within protected areas, suggesting that fish conservation will require active management and targeted river restoration outside of reserves. These results provide the foundation for systematic freshwater conservation planning in California and for prioritizing where limited resources are allocated for fish recovery and protection.

Highlights

Worldwide, freshwater ecosystem degradation and loss of freshwater biodiversity and are strongly linked to human development pressures (Vörösmarty et al 2010, Limburg et al 2011)
We quantify the spatial concordance of high-priority catchments among different taxonomic groups and with the existing protected area network. These analyses provide the foundation for strategic freshwater fish conservation planning in California
Local extirpations of anadromous taxa are concentrated along the coast in northern-central California and in tributaries to the Sacramento and San Joaquin Rivers (Figure 2B), especially in areas where fish passage has been blocked by major dams (e.g., Shasta Dam on the Sacramento River)

Summary

Introduction

Freshwater ecosystem degradation and loss of freshwater biodiversity and are strongly linked to human development pressures (Vörösmarty et al 2010, Limburg et al 2011). Decline of the state’s native fish fauna highlights the failure of past and ongoing management efforts to protect freshwater biodiversity and ecosystems. This is in spite of the fact that substantial resources have been invested in fish conservation and recovery programs. The current role of, and potential for, protected areas for conserving freshwater biodiversity in California remains poorly understood. In light of these deficiencies, some have argued that a strategic, statewide plan for freshwater fish conservation that includes designated priority catchments for aquatic biodiversity management is warranted (Moyle 2002; Moyle and Yoshiyama 1994).

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Conclusion