Research Projects 2018-2020

Land-based pollutants in herbivorous reef fishes on Hawaiian reefs

PRINCIPAL INVESTIGATOR: Megan Donahue
Co-INVESTIGATOR: Stephen Karl
Graduate Trainee: Julie Zill

Construction cranes tower over the buildings and houses of urban Oʻahu.
Urban Oʻahu leaks pollutants, like metals, from many sources into the surrounding coastal waters, threatening fragile coral reef ecosystems and reef fish.

Pollutants, such as metals, pose a serious threat to coral reef ecosystems. In the past century Hawaiʻi has experienced significant changes in land use, and on Oʻahu in particular many areas have transitioned from forest to farmland to urban development. Urban areas can have high concentrations of metal pollutants that contaminate nearby watersheds. Once in urban streams these metals can get carried with sediment onto coral reefs as runoff. Herbivorous reef fishes that eat turf algae and sediment are critical to the maintenance of healthy coral reefs, but they may also be particularly vulnerable to land-based pollutants found in the sediment. Many of these fishes, such as manini and kole, are targeted by fishermen and have cultural significance, so it is important that we understand whether or not they are accumulating these metals in their tissues. This project will compare the metal concentrations in muscle tissue from reef fishes collected at sites that vary in their contamination to identify species and locations that are most impacted by metal pollution. The results will be shared with local communities and can be used by resource managers to minimize the influence of land-based pollutants on coral reefs. The information generated will also be applicable to coral reefs around the world as development spreads to more islands and coastal areas.