Filling the Knowledge Gaps: Extreme Weather Driven Changes in Streamflow Patterns and their Impacts on Fish in Hawaiian Streams

Freshwater is a critical driver for island ecosystems and essential part of the water cycle in tropical islands, which is threaten by climate change.  Changes in streamflow patterns may impact streams, estuarine, and coastal habitats. In Hawai‘i, these habitats support five native stream fish species. To examine how changes in streamflow have impacted habitat quality for these native aquatic species, an ongoing project has been examining statewide long-term stream records.  

This study will examine historical extreme weather patterns, including flood and drought, to describe the characteristics and flow patterns of stream habitats in Hawaiʻi. This information will then be associated with observed fish populations and behaviors to better understand the effects of extreme weather on native fish in a few selected streams. Researchers will then analyze stream temperature changes with a goal to describe current and future streamflow and stream thermal dynamics under a changing climate.  Community perspectives on the social and cultural values of these species and ecosystems will also be incorporated.  

The need for information on the effects of extreme weather-driven changes in streamflow and fish populations has arisen from discussions with local stakeholders (e.g., Commission on Water Resource Management, Hawai’i Fish Habitat Partnership, National Fish Habitat Partnership, Pacific Island Fisheries and Wildlife Services), and the results will inform management decisions aimed at mitigating the impacts of climate change on Hawaiian streams and ecosystems.