Emigration of Juvenile Atlantic Croakers, Micropogon undulatus, from a Semi-impounded Marsh in Southwestern Louisiana

Abstract

Abstract Descriptions of the emigration patterns of juvenile Atlantic croakers, Micropogon undulatus, from their nurseries have varied from (1) gradual seaward movements, to (2) mass outward movements, to (3) a “bleeding off” of the larger individuals. The present study was conducted at a semi-impounded marsh within a few kilometers of the Gulf of Mexico. Emigration patterns were monitored by trawling within the nursery and continuous trapping in the nursery outlet. Early in the year (February and March) croakers were small and tended to move in and out of the nursery with the tide. Thereafter there was an increasing divergence in the size of trawl- and trap-caught croakers; the fish taken in the trap were consistently the larger, indicating that the larger juveniles were continually “bleeding off” and emigrating back to the Gulf.