t. The researchers record the location of every fish reeled in and correlate that information with seafloor images they get from a sonar fish finder. They note each individual’s sex, length and weight, then throw it back. These fishing trips, combined with observations made in submersible dives, are painting a picture of the lives of these little-known species.
Kelley has found that adult fish prefer craggy outcrops, while the young seem to hover over lower relief outcrops. Ehu live closer to the bottom, while onaga school several meters above it. Kelley has surveyed bottom fish habitat throughout the main Hawaiian Islands, and in several months, he will present his recommendations for Hawaii’s 19 bottom fish reserves to the state government. The areas were set up with scant knowledge of the type and location of critical fish habitat. Now, Kelley’s data shows that at least two of the reserves are misplaced, lacking the jagged topography the fish call home.
In Pupukea on the north shore of Oahu, I follow Carl Meyer, a graduate student at the University of Hawaii, into the water. He shows me how easy it is to catch fish at night, bare-handed. Shine a light into their eyes and they freeze like deer on a road. He grabs a striped convict tang. In one study, Meyer caught dozens of fish, tagged them with ultrasonic transmitters and released them. Then, to learn their movement patterns, he paddled after them in his hydrophone-equipped kayak.
He discovered that the three species he tracked (blue spine unicorn fish, yellowstripe goatfish and blue jack) all had well-defined home ranges. With the regularity of bank employees, they commuted daily between their sleeping areas in the reef and their feeding grounds. While unicorn fish stayed within the reserve, the goatfish and jack had home ranges three times the reserve size, exposing them to daily danger. Meyer concluded that tripling the reserve’s size, which is currently a mere tenth of a square mile, would protect these mobile species.
In a statement issued last autumn, 161 of the nation’s leading marine scientists suggested that reserves strung together like pearls would provide maximum protection, reseeding each other as well as the nearby fishing areas. Designing optimal reserves therefore requires knowledge of current patterns, larval transport routes and fish movement—there is still much left to learn.