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III-E-12 



Jones, R.R. 1973. Utilization of Louisiana estuarine sediments as a 



source of nutrition for the brown shrimp Penaeus aztecus . Ph.D. 



Thesis. Louisiana State University. 140 pp. TOiss. Abstr. 35:1127-B) 



An investigation of food habits of juvenile Penaeus aztecus 

 was conducted in Airplane Lake, a small tidal pond in the marsh bordering 

 Barataria Bay, Louisiana. Results indicated that younger juveniles 

 were encounter feeders utilizing the detrital organics and associated 

 microfauna of the bottom substrate. As the shrimp matured, they became 

 increasingly predatory on benthic macrofauna. Change to a predatory 

 feeding habit was reflected by increase in organic assimilation effi- 

 ciency. Juvenile shrimp fed most effectively in the shore zone of 

 Airplane Lake where concentrations of organic detritus, microorganisms 

 and benthic meiofauna were highest. 



Selection for organic particles and assimilation efficiency increased 

 with shrimp size. An average organic assimilation efficiency of 41 

 percent in larger juveniles (65-84 mm) was about double the efficiency 

 recorded in smaller juveniles (21 percent at 25-44 mm). In contrast; 

 protein assimilation efficiency declined with size. 



Visual and chemical analyses of particulate content of sediment 

 revealed greatest concentrations of organic detritus and benthic 

 meiofauna along the shoreline. Highest protein concentrations were 

 associated with fine detrital fractions below 160 microns particle 

 diameter. (A. A.) 



Keywords: detritus, brown shrimp, Louisiana 



III-E-13 



Welsh, B.L. 1973. The grass shrimp, Palaemonetes pugio , as a major 



component of salt marsh ecosystem. Ph.D. Thesis. University of Rhode Island. 



97 pp. (Diss. Abstr. 34:2764-B) 



The grass shrimp, Palaemonetes pugio , was studied in its role as a 

 dominant species uniquely adapted to a highly stressed tidal marsh embayment. 

 Monthly sampling of length and dry weight revealed that its life cycle 

 was a single year, with spawning in May, June and July and heaviest growth 

 in late summer and fall. Mark and recapture estimates conducted quarterly 

 and quadrat net estimates calculated monthly indicated that shrimp were 

 present throughout the year with peak densities in the fall (over 1.2 

 million in 2-1/2 acres in October). Production of biomass (growth) 

 equalled loss to predation (including decomposition) over the annual 

 cycle. 



Microcosm studies and observations by seaming electron microscope 

 revealed that the shrimp mascerated detritus into a heterogeneous assortment 

 of uneaten particles by plucking away the cellular matrix from surfaces 



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