Movement of Gulf Menhaden through Three Marshland Routes in Southwestern Louisiana

Abstract

Abstract The life history of gulf menhaden Brevoortia patronus and their movements through three routes between the marsh and the Gulf of Mexico were studied to determine ways to facilitate passage of these fish through existing and proposed water-control structures. We used stationary traps at the water surface, mid-depth, and bottom of the channels; most gulf menhaden were captured in the upper two-thirds of the water column. Indirect evidence indicated that spawning occurred from late August to May. Apparently, low dissolved oxygen sometimes forced the fish to emigrate in summer. Compared to those of earlier studies done in more open-water situations, our highest catches occurred at considerably higher salinities and lower temperatures. For fisheries, it may usually be best if water-control structures are not installed. If installed, such structures should allow maximum migration past the structure. To allow aquatic species to escape from lethal conditions, the structures should have permanent openings...