Effect of Drawdowns on Fishery Harvest 



Drawdowns appeared to adversely affect freshwater game fish populations such as bluegill 

 (Lepomis macrochirus), black crappie (Pomoxis nigromaculatus), and largemouth bass (Micropterus 

 salmoides). Although deep ditching afforded fish some refuge, fish kills associated with low 

 dissolved oxygen were occasionally observed in the ditches. Game fish populations appeared to be 

 most abundant 2-3 years following a complete drawdown and were capable of supporting moderate 

 fishing pressure. It is not certain, however, whether the population rebound was from the 

 reproduction of surviving fish or from reproduction of new recruits. Largemouth bass weighing 1.1- 

 1.5 kg were occasionally caught during the third year following a complete drawdown. 



Dewatered brackish and semi-impoundments were often reflooded with brackish waters to 

 maximize ingress of estuarine organisms. 



CONCLUSIONS 



Water level and salinity management within semi-impoundments was successful in stimulating the 

 growth of preferred waterfowl food plants and enhancing waterfowl habitat. Waterfowl harvest 

 analysis indicated a significant difference (P<.05) between the development and management stages 

 of the marsh management program. Fur harvests at LPWMA were equal to or greater than 

 corresponding harvests from the intermediate and brackish marshes of the Louisiana Chenier Plain. 

 The 11-year average alligator harvest success rate for LPWMA (99.3%) exceeded the corresponding 

 average success rate for the State of Louisiana (94.4%). Management of fresh and intermediate 

 semi-impoundments allowed simultaneous production of estuarine organisms and the maintenance 

 of freshwater game fish populations. Brackish water impoundments were successfully managed to 

 enhance wildlife habitat and estuarine organism productivity. 



Habitat deterioration was reversed by implementing established and experimental marsh 

 management practices. Drawdowns, water level management, and water salinity management caused 

 both emergent and submergent vegetation to flourish within semi-impoundments. 



Nine location canals were dredged on LPWMA from 1975 to 1987. Mineral activities were 

 modified to minimize detrimental environmental impacts and remain compatible with marsh 

 management goals. Results achieved during 12 years of intensive marsh management at LPWMA 

 indicate that the program was a success. 



LITERATURE CITED 



Adams, W.H. 1956. Ecological studies of coastal marsh in the vicinity of Price Lake, Rockefeller 

 Refuge, Cameron Parish, Louisiana. M.S. Thesis. Louisiana State University, Baton Rouge. 118 

 pp. 



Beule, J.D. 1979. Control and management of cattails in southeastern Wisconsin wetlands. 

 Wisconsin Department of Natural Resources Technical Bulletin No. 112, Madison. 41 pp. 



Burgess, H.H. 1969. Habitat management on a mid-continent waterfowl refuge. J. Wildl. Man. 

 33(4): 843-847. 



Chabreck, R.H. 1960. Coastal marsh impoundments for ducks in Louisiana. Proc. Annu. Conf. 

 Southeast. Assoc. Game Fish Comm. 14:24-29. 



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