Minello TJZimmerman RJMartinez EXTransactions of the American Fisheries Society2010-02-152010-02-151989http://hdl.handle.net/1969.3/23076693-708We estimated actual 2-week mortalities of postlarval and juvenile brown shrimp (Penaeus aztecus ) in a Galveston Bay salt marsh by comparing densities of cohorts throughout the spring. Mortalities ranged between 33% and 61% in 1982 and 23% and 39% in 1987. Brown shrimp mortality in predator-exclusion cages during 1987 was less than 3%. These data and published information on food requirements, diseases, and physical tolerances suggest that predation is usually the major direct cause of brown shrimp mortality in estuarine nurseries of the northern Gulf of Mexico. Southern flounder Paralichthys lethostigma was the dominant fish predator on brown shrimp during the spring, and appeared to be responsible for a large portion of brown shrimp mortality. In laboratory experiments, the presence of smooth cordgrass Spartina alterniflora reduced predation rates of southern flounder and some of the other fish predators examinedASW,Galveston BayD 04665 CrustaceansdiseasesestuariesfishFishery biologyGalveston BayGulf of MexicoLaboratoriesMortalityMortality causesO 5020 FISHERIES,FISHERY BIOLOGY,FISHINGPenaeus aztecuspopulation dynamicsPredationQ1 01442 Population dynamicsrecruitmentShrimp fisheriesSpartinaSpartina alternifloraspringToleranceUSAUSA,Texas,Galveston BayJournal