A state aquatics biologist, Skippy Hau, who has been studying the health of stream fauna around Maui, advocates restoring as much water as possible to the streams to allow the native species to recover.

Hawaii streams contain five types of oopu, or gobies, four of which are endemic to Hawaii. There also are two endemic shrimps, or opae, and three species of endemic snails.

"The life cycle of most stream animals requires a connection to the ocean," Hau said. "Larvae hatch in streams and are carried to the ocean. They return as post-larvae and migrate upstream under normal flow conditions."

Hau said heavy rains that cause streams to overflow diversions and wash sediment and organic materials into the ocean may help to guide the post-larval oopu, opae and snails to streams and provide nutrients in the estuaries where the young animals aggregate before moving upstream.

The lack of pathways for the young animals when the streambeds dry up due to diversions concerns Hau.