Population Structure and Life History Connectivity of Red Hake (Urophycis chuss) Along the Northeast United States Continental Shelf

We used a multidisciplinary approach to examine population structure of red hake (Urophycis chuss), a species affected by climate-related change along the Northeast United States continental shelf. Lagrangian particle simulations predicted regional retention of pelagic early stages, and age structure showed strong spatial heterogeneity, consistent with a management hypothesis of stock separation between the Gulf of Maine and Mid-Atlantic Bight. However, the chemistry of otolith nuclei showed no differences. These results can be explained by recruitment from a common source during early life with subsequent separation and independent rates of mortality. Evidence of similar regional growth rates and environmental exposures from age-at-length and edge chemistry corroborated adult restriction to temperature-favorable habitat. Using the Lagrangian simulations, we hypothesize that the population depends on spawning on the Georges Bank, where the gyre structures the trajectory that fish must follow to close their life cycle. Distributions of red hake may remain stable in the near future, because the critical life history trajectory occupies an area removed from the species’ temperature limitations.