Eddies in the Hawaiian Archipelago Region: Formation, Characterization, and Potential Implications on Larval Retention of Reef Fish

Abstract

Here we present an assessment of eddy activity in a 3,500 × 2,000 km region of the North Pacific. Eddies were identified and tracked within a numerical simulation that used the Massachusetts Institute of Technology general circulation model and an eddy characterization algorithm. Spatially, eddy births were more frequent: (1) nearshore (cyclones) and offshore (anticyclones) on the windward side of the main Hawai‘ian Islands; (2) in patches of cyclones and anticyclones that resembled the dipole structure of wind stress curl along the islands’ leeward side; and (3) in zonal patches of eddies of both polarities west and north of the islands. Temporally, high eddy activities occurred in spring. There was a meridional distribution of eddy lifespans, which increased northward. Cyclones were more abundant, longer-lived, smaller, and more nonlinear. Reef fish spawning locations in Hawai‘i coincide with the regions of high eddy activity, with nonlinear eddies responsible for high larval retention.