Feasibility of Trap and Transport of Adult River Herring to Restore Spawning Populations in A Southeastern U.S. Coastal Watershed

Adult alewife (Alosa pseudoharengus) and blueback herring (A. aestivalis) (collectively referred to as river herring) have rarely been trapped and transported during the spawning period to restore spawning runs in southern coastal U.S. watersheds, though this is a common practice in New England. We tested the feasibility of this practice in North Carolina to develop a protocol to assist in restocking and conservation efforts. River herring were collected using pound nets in the Scuppernong River at Columbia, North Carolina, from February-April 2007. Fish were removed from pound nets, placed into an oxygenated 833-L holding tank, and transported approximately 30 min to Lake Phelps, a natural Carolina Bay lake on the Albemarle-Pamlico peninsula with an outlet to Albemarle Sound. The density of river herring in the tank was maintained < 1 fish / 3.78 L-1. Survival of river herring associated with capture and transport to the stocking site was 88% each, and was not related to water temperature (range, 9.2-18.7 C). Overall survival after trap, transport, and holding for 24 h in cages was 28.1%, but survival was 68% at water temperatures ≤12 C and 10.6% at water temperatures >12 C. No juvenile river herring were collected in Lake Phelps, thus the success of trap and transport to create a spawning population was unable to be determined. Trap and transport may be most appropriate for alewife because they enter the spawning areas before the water reaches 12 C. The success of river herring trap and transport may ultimately depend on the number of spawning adults relocated to a depleted system and the environmental conditions experienced by early life stages of spawned river herring. Results of this study demonstrated that trap and transport can be conducted successfully in coastal systems of the southeastern United States; however, the issue of the efficacy of this method to restore spawning runs remains unresolved.

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