intermediate water body, which also served as a refuge for alligators during periods of high 

 salinities. Water level and salinity stabilization enhanced alligator habitat on LPWMA 



Effects of Drawdowns on Alligator Harvest 



Drawdowns did not appear to adversely affect success of alligator harvests at LPWMA. The 

 average alligator hunter success rate was 99.7% during drawdown years and 99.0% during non- 

 drawdown years. Drawdowns did not appear to adversely affect success of alligator harvests at 

 LPWMA (Table 7). Deep tranasses and borrow pits helped maintain alligator habitat within semi- 

 impoundments during drawdowns. Although some alligators may have temporarily left dewatered 

 semi-impoundments, adjacent permanent water bodies such as Little Pecan Lake, Little Pecan 

 Bayou, and oilfield canals provided ample habitat. 



Fisheries Harvest 



White shrimp catches in 1984 and 1986 were conservatively estimated to average approximately 

 746 kg/yr or 1.8 kg/ha/yr. In 1985, white shrimp recruitment and productivity within Little Pecan 

 Lake was excellent, until the crash of a heavy algae bloom in late October. Oxygen depletion 

 associated with this algae bloom killed a considerable number of fish and shrimp. Subsequently, 

 white shrimp catch decreased (approximately 559.5 kg/yr). 



In addition to providing good catches of white shrimp and occasionally brown shrimp, blue crabs 

 were also numerous within the lake. Hundreds of crabs were harvested annually for personal 

 consumption. 



Blue catfish (Ictalurus furcatus) and channel catfish (Ictalurus punctatus) were abundant within 

 Little Pecan Lake. It was estimated that several thousand kilograms of live catfish were removed 

 annually from the lake. Channel catfish averaged 0.47-0.75 kg, whereas the blue catfish averaged 

 0.75-1.9 kg. Individual blue catfish weighing 3.7-7.5 kg were frequently caught and the largest blue 

 catfish ever caught in Little Pecan Lake weighed 19.4 kg. Observation of catfish stomach contents 

 indicated that catfish preyed heavily on white shrimp from October through December. 



Game fish populations within the lake were low. Despite attempts to renovate the entire fish 

 population, catfish have always dominated the fishery. 



Harvest of Fishery Resources within Brackish Semi-impoundments 



When ample recruitment opportunities were provided, densities of white shrimp within semi- 

 impounded marshes appeared in some cases to be equivalent to that of adjacent unmanaged 

 marshes. Several factors may have contributed to high shrimp catches in semi-impoundments: 1) 

 abundant aquatic vegetation within semi-impounded marshes provided more cover, edge, and 

 greater quantities of epiphytic food organisms; 2) fewer shrimp predators were found within semi- 

 impoundments; 3) predator foraging activities were restricted by dense growths of aquatic vegetation 

 and shallow water levels; 4) the extensive tranasse system improved access to isolated ponds; and 

 5) dewatered semi-impoundments were occasionally reflooded with brackish water to maximize 

 ingress. 



In some instances, recruitment opportunities into semi-impoundments were not made available 

 to estuarine organisms. Low densities of shrimp and other estuarine organisms were nevertheless 

 often found within those semi-impoundments because leaking water control structures 

 unintentionally provided recruitment opportunities. 



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