Spontaneous necroses in muscles of brown shrimp, Penaeus aztecus Ives.

Brown shrimp (Penaeus aztecus) caught in trawls in Galveston Bay and kept in poorly aerated tanks frequently have macroscopic focal, irregular, white areas in the muscles of different segments of the abdomen. When the shrimp are placed in well aerated tanks, some of this discoloration may regress within 24 hours. Similar areas of discoloration are sometimes present in shrimp immediately after being caught in the Bay. These white areas histologically are degenerated foci of striated muscle. When the muscular involvement is extensive, the shrimp may die in 18-24 hours. This muscle necrosis may be a metabolic reaction caused by high temperature, anoxia, and stress.