Climate change and conservation of endemic amphidromous fishes in Hawaiian streams

Abstract

Amphidromous fishes are important members of oceanic island freshwater communities. Although often depauperate, amphidromous fish assemblages on islands are largely composed of endemic species. Little is known about the effects of anthropogenic stressors on amphidromous fishes, and the consequences of climate-driven changes in water quality and quantity are particularly uncertain. Focusing on native fishes in Hawaii, we discuss the potential for climate change to intensify 3 major threats facing amphidromous fish: (1) loss of 'ridge-to-reef' migratory corridors via disruption of surface water connectivity, (2) in-stream habitat degradation and (3) exotic species introductions. Successfully addressing these and other threats to native fish in Hawaii will require approaches that balance conservation needs with use of water resources. Conservation initiatives should focus on 'scaling up' ongoing projects intended to demonstrate how stream protection and restoration, non-native species removal and reintroductions can benefit at-risk species. Research initiatives should focus on determining the ecological controls on recruitment under current and future climate conditions.