Routes and rates of larval fish transport from the southeast to the northeast United States continental shelf

Abstract

Larval fish originating south of Cape Hatteras, North Carolina, are frequently found on the continental shelf north of Cape Hatteras, even as far north as the Scotian shelf. The Gulf Stream and associated warm‐core rings are hypothesized as the physical mechanisms responsible for the northward transport of larvae. Specifically, larvae spawned along the southeast U.S. continental shelf are entrained into the Gulf Stream, transported to the northeast, regularly incorporated in warm‐core ring streamers, transported across the slope region, and released along the shelf edge north of Cape Hatteras. This proposed transport route was evaluated using hydrographic data and drifter tracks that were collected as part of other studies. Continental shelf water that originated south of Cape Hatteras was found along the edge of the Gulf Stream north of Cape Hatteras, and drifter tracks demonstrated each segment of the proposed transport route. A probability model was then developed to estimate transport times for larvae carried over the proposed transport route using a combination of sea surface temperature images, statistics of drifter transport speeds, and a larval mortality function. Modeled transport time distributions closely matched observed age distributions of larvae, further supporting the hypothesized transport route.