Publication Date:
2021-07-01
Description:
Serial, cyclonic, mesoscale eddies arise just north of the Charleston Bump, a topographical rise on the continentalslope and Blake Plateau, and characterize the U.S. outer shelf and upper slope in the region of the Charleston Gyre.This region was transected during the winters of 2000, 2001, and 2002, and hydrographic data and larval fishes werecollected. The hydrodynamics of the cyclonic eddies of the Charleston Gyre shape the distribution of larval fishes bymixing larvae from the outer continental shelf and the Gulf Stream and entraining them into the eddy circulation atthe peripheral margins, the wrap-around filaments. Over all years and transects (those that intercepted eddies andthose that did not), chlorophyll a concentrations, zooplankton displacement volumes, and larval fish concentrations were positively correlated. Chlorophyll a concentrations were highest in filaments that wrapped around eddies, and zooplankton displacement volumes were highest in the continental shelf–Gulf Stream–frontal mix. Overall, the concentration of all larval fishes declined from inshore to offshore with highest concentrations occurring over the outer shelf. Collections produced larvae from 91 fish families representing continental shelf and oceanic species. The larvae of shelf-spawned fishes—Atlantic Menhaden Brevoortia tyrannus, Round Herring Etrumeus teres, Spot Leiostomus xanthurus, and Atlantic Croaker Micropogonias undulatus—were most concentrated over the outer shelf and in the continental shelf–Gulf Stream–frontal mix. The larvae of ocean-spawned fishes—lanternfishes, bristlemouths, and lightfishes—were more evenly dispersed in low concentrations across the outer shelf and upper slope, the highest typically in the Gulf Stream and Sargasso Sea, except for lightfishes that were highest in the continental shelf–Gulf Stream–frontal mix. Detrended correspondence analysis rendered groups of larval fishes that corresponded with a gradient between the continental shelf and Gulf Stream and Sargasso Sea. Eddies propagate northeastward with a residence time on the outer shelf and upper slope of ∼1 month, the same duration as the larval period of most fishes. The pelagic habitat afforded by eddies and fronts of the Charleston Gyre region can be exploited as nursery areas for feeding and growth of larval fishes within the southeastern Atlantic continental shelf ecosystem of the U.S. Eddies, and the nursery habitat they provide, translocate larvae northeastward.
Keywords:
Ecology
;
Fisheries
;
Oceanography
Repository Name:
AquaDocs
Type:
article
,
TRUE
Format:
application/pdf
Format:
application/pdf
Format:
246-259
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